Patent Application
20220314545
The present specification generally relates to additive manufacturing apparatuses and methods for using the same.
Additive manufacturing apparatuses may be utilized to “build” an object from build material, such as organic or inorganic powders, in a layer-wise manner. Existing additive manufacturing apparatuses may not meet demands in terms of efficiency, throughput, and/or quality.
Accordingly, a need exists for alternative additive manufacturing apparatuses and components thereof that improve efficiency, throughput, and/or quality.
In an aspect, a method of building an object by additive manufacturing comprises pre-heating a deposition region of a build chamber to a pre-heat temperature; distributing a layer of build material on a build platform positioned within the build chamber with a recoat assembly moving in a coating direction; depositing a layer of binder material on the layer of build material; irradiating the layer of build material with an energy source coupled to the recoat assembly; adjusting a position of the build platform such that a portion of build material and binder is within a curing region of the build chamber, wherein the curing region of the build chamber is below the deposition region of the build chamber; heating the curing region of the build chamber to a curing temperature, wherein the curing temperature is greater than the pre-heat temperature; curing the binder within the curing region of the build chamber; and distributing a new layer of build material above the portion of build material and binder on the build platform.
In another aspect, a method of building an object by additive manufacturing comprises: moving a recoat assembly over a build material with a recoat head actuator, the recoat head actuator comprising a recoat motion axis, whereby actuation of the recoat head actuator along the recoat motion axis in a first recoat direction causes the recoat assembly to move in the first recoat direction, and wherein the recoat assembly comprises a first roller and a second roller that is spaced apart from the first roller; rotating the first roller of the recoat assembly in a counter-rotation direction, such that a bottom of the first roller moves in the first recoat direction; contacting the build material with the first roller of the recoat assembly, thereby fluidizing at least a portion of the build material; irradiating, with a front energy source coupled to a front end of the recoat assembly, an initial layer of build material positioned in a build area; subsequent to irradiating the initial layer of build material, spreading the build material on the build area with the first roller, thereby depositing a second layer of the build material over the initial layer of build material; subsequent to spreading the second layer of the build material, irradiating, with a rear energy source positioned rearward of the front energy source, the second layer of build material within the build area; and depositing a binder material on the second layer of build material with a print head coupled to a print head actuator, the print head actuator comprising a print motion axis whereby the binder material is deposited with the print head by actuating the print head actuator along the print motion axis in a first print direction opposite the first recoat direction, wherein the recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in a vertical direction.
In another aspect, a method for forming an object with an additive manufacturing system comprises a supply platform, a cleaning station, and a build area horizontally positioned between the cleaning station and the supply platform, wherein the cleaning station comprises a binder purge bin and a cleaning station vessel having cleaning fluid therein and comprising a wet wipe cleaner section, and a dry wipe cleaner section, the method comprising: distributing a new layer of build material on the build area with a recoat assembly coupled to a recoat head actuator, the recoat head actuator comprising a recoat motion axis whereby actuation of the recoat head actuator along the recoat motion axis in a first recoat direction causes the recoat assembly to distribute the new layer of build material on the build area; depositing a binder material on the new layer of build material with a print head coupled to a print head actuator, the print head actuator comprising a print head motion axis whereby the binder material is deposited with the print head by actuating the print head actuator along the print head motion axis in a first print direction opposite the first recoat direction, where the recoat motion axis and the print head motion axis are parallel to one another and spaced apart from one another in a vertical direction; passing the print head over the binder purge bin to facilitate discharge of contaminants from the print head via backpressure; introducing the print head to the wet wipe cleaner section so that cleaning fluid is applied to the print head by a wet wipe member; and introducing the print head to the dry wipe cleaner section so that cleaning fluid is removed by a dry wipe member and the print head is thereby cleaned.
In another aspect, a method of building an object by additive manufacturing comprises: distributing a layer of build material on a build platform with a recoat head that is coupled to a recoat head actuator configured to move the recoat head along a longitudinal axis during distribution of the layer of build material; depositing binder through select ones of a plurality of jet nozzles of a printing head onto the layer of build material as the printing head traverses a first pass trajectory along a longitudinal axis in a first direction; indexing the printing head along a latitudinal axis to a second pass trajectory by an index distance; depositing binder through select ones of the plurality of jet nozzles of the printing head as the printing head traverses the second pass trajectory along a longitudinal axis in a second direction opposite the first direction; and distributing a new layer of build material above the layer of build material and binder on the build platform.
Additional features and advantages of the additive manufacturing apparatuses described herein, and the components thereof, will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.
Reference will now be made in detail to embodiments of additive manufacturing apparatuses, components thereof, and methods for using such apparatuses and components, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. One embodiment of an additive manufacturing apparatus 100 comprising an actuator assembly 102 for distributing build material and depositing binder material is schematically depicted in
Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
Directional terms as used herein—for example up, down, right, left, front, back, top, bottom, upper, lower, —are made only with reference to the figures as drawn and are not intended to imply absolute orientation unless otherwise expressly stated.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.
As used herein, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.
Referring now to
In operation, build material 31, such as organic or inorganic powder, is positioned on the supply platform 30. The supply platform 30 is actuated to present a layer of the build material 31 in the path of the build head 15. The build head 15 is then actuated along the working axis of the conventional additive manufacturing apparatus 10 from the home position 12 towards the build platform 20 in the direction indicated by arrows 40. As the build head 15 traverses the working axis over the supply platform 30 towards the build platform 20, the build head 15 distributes the layer of build material 31 in the path of the build head 15 from the supply platform 30 to the build platform 20. Thereafter, as the build head 15 continues along the working axis over the build platform 20, the build head 15 deposits a layer of binder material 50 in a predetermined pattern on the layer of build material 31 that has been distributed on the build platform 20. Optionally, after the binder material 50 is deposited, an energy source within the build head 15 is utilized to cure the deposited binder material 50. The build head 15 then returns to the home position 12 where at least a portion of the build head 15 is positioned over the cleaning station 11. While the build head 15 is in the home position 12, the build head 15 works in conjunction with the cleaning station 11 to provide cleaning and maintenance operations on the elements of the build head 15 which deposit the binder material 50 to ensure the elements are not fouled or otherwise clogged. This ensures that the build head is capable of depositing the binder material 50 in the desired pattern during a subsequent deposition pass. During this maintenance interval, the supply platform 30 is actuated in an upward vertical direction (i.e., in the +Z direction of the coordinate axes depicted in the figure) as indicated by arrow 43 to present a new layer of build material 31 in the path of the build head 15. The build platform 20 is actuated in the downward vertical direction (i.e., in the −Z direction of the coordinate axes depicted in the figure) as indicated by arrow 42 to prepare the build platform 20 to receive a new layer of build material 31 from the supply platform 30. The build head 15 is then actuated along the working axis of the conventional additive manufacturing apparatus 10 again to add another layer of build material 31 and binder material 50 to the build platform 20. This sequence of steps is repeated multiple times to build an object on the build platform 20 in a layer-wise manner.
Such conventional additive manufacturing apparatuses may also not meet demands with respect to efficiency, throughput, and/or quality.
The embodiments described herein are directed to additive manufacturing apparatuses, components for additive manufacturing apparatuses, and methods for using such additive manufacturing apparatuses and components, which may be implemented to improve efficiency, throughput, and/or quality.
Referring now to
While specific embodiments in the following description relate to additive manufacturing apparatuses utilizing the deposition or printing of a “binder” by a print head and subsequent curing to facilitate consolidation of the build material, it is expressly contemplated that the architecture of the various additive manufacturing apparatuses described herein (e.g., the positioning and layout of the cleaning station, build platform, supply platform, etc. and/or the actuator assemblies associated with the print head and recoat head) may be utilized for other additive manufacturing modalities. For example, the print head associated with the actuator assemblies described herein may be substituted for one or more energy beam sources, such as laser sources or electron beam sources, for example, commonly used to consolidate build materials in additive manufacturing apparatuses and additive manufacturing processes. In these embodiments, the steps of printing binder with a print head and curing binder to consolidate build material would be replaced with consolidating the build material by directing an energy beam of the energy beam source to facilitate consolidation. The energy beam source may be traversed and maneuvered with the actuator assemblies described herein the same as the print head embodiments. Thus, the “print head” of the embodiments described herein could be referred to as a “consolidation head” and the consolidation head may be a print head or an energy beam source. Further, in as much as additive manufacturing processes may be described as “printing” discrete, consolidated layers of a build to form an object, the various uses of the term “print” as a modifier (e.g., print home position, print head actuator, print return rate, etc.) may be substituted for “consolidation” as the modifier (e.g., consolidation home position, consolidation head actuator, consolidation return rate, etc.), such as when the consolidation head is an energy beam source.
Further, with respect to a maintenance station described herein, when an energy beam source is substituted for the print head described herein, it is contemplated that the maintenance station may be used to facilitate cleaning of the energy beam source, to remove soot particles, melt spatter, and the like, in a similar manner as the cleaning stations described herein. In addition or as an alternative to cleaning, the maintenance station may also include a calibration station or calibration feature to allow for calibration (or re-calibration) of the energy beam source. In some of these embodiments, a maintenance station may not be employed, such as in embodiments where the additive manufacturing apparatus utilizes an energy beam source without a maintenance station. In such embodiments the “print home” position described herein would function as a homing position for parking the associated consolidation head.
Referring again to
The cleaning station 110 is positioned proximate one end of the working axis 116 of the apparatus 100 and is co-located with the print home position 158 where the print head 150 is located or “parked” before and after depositing binder material 500 on a layer of build material 400 positioned on the build platform 120. The cleaning station 110 may include one or more cleaning sections (not shown) to facilitate cleaning the print head 150 between depositing operations. The cleaning sections may include, for example and without limitation, a soaking station containing a cleaning solution for dissolving excess binder material on the print head 150, a wiping station for removing excess binder material and excess build material from the print head 150, a jetting station for purging binder material and cleaning solution from the print head 150, a park station for maintaining moisture in the nozzles of the print head 150, or various combinations thereof. The print head 150 may be transitioned between the cleaning sections by the actuator assembly 102.
The build platform 120 is coupled to a lift system 800 comprising a build platform actuator 122 to facilitate raising and lowering the build platform 120 relative to the working axis 116 of the apparatus 100 in a vertical direction (i.e., a direction parallel to the +/−Z directions of the coordinate axes depicted in the figures). The build platform actuator 122 may be, for example and without limitation, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, or any other actuator suitable for imparting linear motion to the build platform 120 in a vertical direction. Suitable actuators may include, without limitation, a worm drive actuator, a ball screw actuator, a pneumatic piston, a hydraulic piston, an electro-mechanical linear actuator, or the like. The build platform 120 and build platform actuator 122 are positioned in a build receptacle 124 located below the working axis 116 (i.e., in the −Z direction of the coordinate axes depicted in the figures) of the apparatus 100. During operation of the apparatus 100, the build platform 120 is retracted into the build receptacle 124 by action of the build platform actuator 122 after each layer of binder material 500 is deposited on the build material 400 located on build platform 120.
The supply platform 130 is coupled to a lift system 800 comprising a supply platform actuator 132 to facilitate raising and lowering the supply platform 130 relative to the working axis 116 of the apparatus 100 in a vertical direction (i.e., a direction parallel to the +/−Z directions of the coordinate axes depicted in the figures). The supply platform actuator 132 may be, for example and without limitation, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, or any other actuator suitable for imparting linear motion to the supply platform 130 in a vertical direction. Suitable actuators may include, without limitation, a worm drive actuator, a ball screw actuator, a pneumatic piston, a hydraulic piston, an electro-mechanical linear actuator, or the like. The supply platform 130 and supply platform actuator 132 are positioned in a supply receptacle 134 located below the working axis 116 (i.e., in the −Z direction of the coordinate axes depicted in the figures) of the apparatus 100. During operation of the apparatus 100, the supply platform 130 is raised relative to the supply receptacle 134 and towards the working axis 116 of the apparatus 100 by action of the supply platform actuator 132 after a layer of build material 400 is distributed from the supply platform 130 to the build platform 120, as will be described in further detail herein.
Referring now to
In one embodiment, such as the embodiment of the actuator assembly 102 depicted in
In the embodiments described herein, the recoat head actuator 144 is coupled to one of the upper support 182 and the lower support 184 and the print head actuator 154 is coupled to the other of the upper support 182 and the lower support 184 such that the recoat head actuator 144 and the print head actuator 154 are arranged in a “stacked” configuration. For example, in the embodiment of the actuator assembly 102 depicted in
In the embodiments described herein, the recoat head actuator 144 is bi-directionally actuatable along a recoat motion axis 146 and the print head actuator 154 is bi-directionally actuatable along a print motion axis 156. That is, the recoat motion axis 146 and the print motion axis 156 define the axes along which the recoat head actuator 144 and the print head actuator 154 are actuatable, respectively. The recoat motion axis 146 and the print motion axis 156 extend in a horizontal direction and are parallel with the working axis 116 (
In the embodiments described herein, the recoat head actuator 144 and the print head actuator 154 may be, for example and without limitation, mechanical actuators, electro-mechanical actuators, pneumatic actuators, hydraulic actuators, or any other actuator suitable for providing linear motion. Suitable actuators may include, without limitation, worm drive actuators, ball screw actuators, pneumatic pistons, hydraulic pistons, electro-mechanical linear actuators, or the like. In one particular embodiment, the recoat head actuator 144 and the print head actuator 154 are linear actuators manufactured by Aerotech® Inc. of Pittsburgh, Pa., such as the PRO225LM Mechanical Bearing, Linear Motor Stage.
In embodiments, the recoat head actuator 144 and the print head actuator 154 may each be a cohesive sub-system that is affixed to the rail 180, such as when the recoat head actuator 144 and the print head actuator 154 are PRO225LM Mechanical Bearing, Linear Motor Stages, for example. However, it should be understood that other embodiments are contemplated and possible, such as embodiments where the recoat head actuator 144 and the print head actuator 154 comprise multiple components that are individually assembled onto the rail 180 to form the recoat head actuator 144 and the print head actuator 154, respectively.
Still referring to
Similarly, the print head 150 is coupled to the print head actuator 154 such that the print head 150 is positioned below (i.e., in the −Z direction of the coordinate axes depicted in the figures) the upper support 182 and the lower support 184. When the actuator assembly 102 is assembled over the cleaning station 110, the build platform 120, and the supply platform 130 as depicted in
In embodiments, the recoat head actuator 144 and the print head actuator 154 overlap over the build receptacle 124, as depicted in
As noted above, in the embodiments described herein the recoat head 140 and the print head 150 are both located on the working axis 116 of the apparatus 100. As such, the movements of the recoat head 140 and the print head 150 on the working axis 116 occur along the same axis and are thus co-linear. With this configuration, the recoat head 140 and the print head 150 may occupy the same space (or portions of the same space) along the working axis 116 of the apparatus 100 at different times during a single build cycle. However, the recoat motion axis 146 of the recoat head actuator 144 and the print motion axis 156 of the print head actuator 154 are spaced apart from one another in a vertical direction due to the stacked configuration of the actuators 144, 154. The spacing of the recoat motion axis 146 and the print motion axis 156 permits the recoat head 140 and the print head 150 to be moved along the working axis 116 of the apparatus 100 simultaneously in a coordinated fashion, in the same direction and/or in opposing directions, at the same speeds or different speeds. This, in turn, allows for individual steps of the additive manufacturing process, such as the distributing step (also referred to herein as the recoating step), the depositing step (also referred to herein as the printing step), the curing (or heating) step, and/or the cleaning step to be performed with overlapping cycle times. For example, the distributing step may be initiated while the cleaning step is being completed; the depositing step may be initiated while the distributing step in completed; and/or the cleaning step may be initiated while the distributing step is being completed. This may reduce the overall cycle time of the additive manufacturing apparatus 100 to less than the sum of the distributing cycle time (also referred to herein as the recoat cycle time), the depositing cycle time (also referred to herein as the print cycle time), and/or the cleaning cycle time.
While
For example,
In the embodiment depicted in
The recoat head actuator 144 and the print head actuator 154 may be bi-directionally actuatable as described herein with respect to
Like, the recoat head actuator 144 and the print head actuator 154, the process accessory actuator 194 may be, for example and without limitation, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, or any other actuator suitable for providing linear motion. Suitable actuators may include, without limitation, a worm drive actuator, a ball screw actuator, a pneumatic piston, a hydraulic piston, an electro-mechanical linear actuator, or the like. In one particular embodiment, the process accessory actuator 194 is a linear actuator manufactured by Aerotech® Inc. of Pittsburgh, Pa., such as the PRO225LM Mechanical Bearing, Linear Motor Stage.
Still referring to
In embodiments, the support brackets 174, 176, 178 may be sized and shaped to allow the support bracket 178 and process accessory 190 attached to the process accessory actuator 194 to nest within the support bracket 174 attached to the print head actuator 154, as depicted in
While
Still referring to
Referring now to
In addition to the nozzles 172, in some embodiment, the print head 150 may further comprise one or more sensors (not depicted) for detecting a property of the build material 400 distributed on the build platform 120 and/or the binder material 500 deposited on the build platform 120. Examples of sensors may include, without limitation, image sensors such as cameras, thermal detectors, pyrometers, profilometers, ultrasonic detectors, and the like. In these embodiments, signals from the sensors may be fed back to the control system (described in further detail herein) of the additive manufacturing apparatus to facilitate feedback control of one or more functions of the additive manufacturing apparatus.
Alternatively or additionally, the print head 150 may comprise at least one energy source (not depicted). The energy source may emit a wavelength or a range of wavelengths of electromagnetic radiation suitable for curing (or at least initiating curing) the binder material 500 deposited on the build material 400 distributed on the build platform 120. For example, the energy source may comprise an infrared heater or an ultraviolet lamp which emit wavelengths of infrared or ultraviolet electromagnetic radiation suitable for curing the binder material 500 previously deposited on the layer of build material 400 distributed on the build platform 120. In instances where the energy source is an infrared heater, the energy source may also preheat the build material 400 as it is distributed from the supply platform 130 to the build platform 120 that may assist in expediting the curing of subsequently deposited binder material 500.
Referring now to
For example,
Referring to
In addition to at least one of a roller 162 and a wiper 166, the recoat head 140 may further comprise at least one energy source. Referring again to
While
In addition to at least one of a roller 162 and a wiper 166, in some embodiments, the recoat head 140 may further comprise at least one sensor 171. Referring again to
While
Referring again to
More specifically, the motion of the recoat head 140, the print head 150, and the process accessory 190 (when included) may be controlled by the control system 200 according to computer readable and executable instructions stored in a memory of the control system 200. It is assumed that the computer readable and executable instructions are formulated to avoid co-locating the recoat head 140, the print head 150, and the process accessory 190 (when included) in the same space (or portions of the same space) along the working axis 116 of the apparatus 100 at the same time during a single build cycle. However, the control system 200 may utilize signal(s) from the working axis proximity sensor to ensure that the recoat head 140, the print head 150, and the process accessory 190 (when included) do not occupy the same space (or portions of the same space) along the working axis 116 of the apparatus 100 at the same time during a single build cycle. If the potential for a collision is determined based on the signals received from the working axis proximity sensor, the control system 200 may change the speed of one or more of recoat head 140, the print head 150, and the process accessory 190 (when included) along the working axis 116 to avoid the collision. Alternatively, if the potential for a collision is determined based on the signals received from the working axis proximity sensor, the control system 200 may halt the additive manufacturing process to prevent damage to one or more of the recoat head 140, the print head 150, and the process accessory 190 (when included).
In some other embodiments, collisions between components may be avoided by knowing the position of the components along the working axis and controlling the positioning of the components with a control system to prevent the components from occupying the same space at the same time. For example, linear encoders may be used in conjunction with the print head actuator and the recoat head actuator (and the knowledge of the dimensions of the print head and recoat head) to determine the position of the print head and the recoat head along the working axis. With this information, the control system can be programmed to avoid collisions between the print head and recoat head based on the location as determined by the linear encoders.
Alternatively or additionally, the additive manufacturing apparatus (specifically the control system) may be programmed to avoid collisions between the print head and the recoat head. For example, using the recoat head start positions with respect to the build platform and the supply platform, the recoat head end positions with respect to the build platform and the supply platform, the speed of the recoat head over the build platform, the speed of the recoat head over the supply platform, the acceleration(s) of the recoat head, the print head start position, the print head end position, the speed of the print head over the print platform, and the acceleration of the print head over the build platform, the motion of the print head and the recoat head can be synchronized and choreographed to avoid collisions.
Referring now to
In the embodiments described herein, the computer readable and executable instructions for controlling the additive manufacturing apparatus 100 are stored in the memory 204 of the control system 200. The memory 204 is a non-transitory computer readable memory. The memory 204 may be configured as, for example and without limitation, volatile and/or nonvolatile memory and, as such, may include random access memory (including SRAM, DRAM, and/or other types of random access memory), flash memory, registers, compact discs (CD), digital versatile discs (DVD), and/or other types of storage components.
The operation of the additive manufacturing apparatus 100 will now be described in further detail with specific reference to
Referring to
In describing the operation of the additive manufacturing apparatus 100, specific reference will be made herein to build material 400 and binder material 500. The build material generally comprises a powder material that is spreadable or flowable. Categories of suitable powder material include, without limitation, dry powder material and wet powder material (e.g., a powder material entrained in a slurry). In embodiments, the build material may be capable of being bound together with the binder material. In embodiments, the build material may also be capable of being fused together, such as by sintering. In embodiments, the build material may be an inorganic powder material including, for example and without limitation, ceramic powders, metal powders, glass powders, carbon powder, sand, cement, calcium phosphate powder, and various combinations thereof. In embodiments, the build material may comprise an organic powder material including, for example and without limitation, plastic powders, polymer powders, soap, powders formed from foodstuff (i.e., edible powders), and various combinations thereof. In some embodiments, the build material may be (or include) pharmaceutically active components, such as when the build material is or contains a pharmaceutical. In embodiments, the build material may be a combination of inorganic powder material and organic powder material.
The build material may be uniform in size or non-uniform in size. In embodiments, the build material may have a powder size distribution such as, for example and without limitation, a bi-modal or tri-modal powder size distribution. In embodiments, the build material may be, or may include, nanoparticles.
The build material may be regularly or irregularly shaped, and may have different aspect ratios or the same aspect ratio. For example, the build material may take the form of small spheres or granules, or may be shaped like small rods or fibers.
In embodiments, the build material can be coated with a second material. For example and without limitation, the build material may be coated with a wax, a polymer, or another material that aids in binding the build material together (in conjunction with the binder). Alternatively or additionally, the build material may be coated with a sintering agent and/or an alloying agent to promote fusing the build material.
The binder material may comprise a material which is radiant-energy curable and which is capable of adhering or binding together the build material when the binder material is in the cured state. The term “radiant-energy curable,” as used herein, refers to any material that solidifies in response to the application of radiant energy of a particular wavelength and energy. For example, the binder material may comprise a known photopolymer resin containing photo-initiator compounds functioning to trigger a polymerization reaction, causing the resin to change from a liquid state to a solid state. Alternatively, the binder material may comprise a material that contains a solvent that may be evaporated out by the application of radiant energy. The uncured binder material may be provided in solid (e.g. granular) form, liquid form including a paste or slurry, or a low viscosity solution compatible with print heads. The binder material may be selected to have the ability to out-gas or burn off during further processing, such as during sintering of the build material. In embodiments, the binder material may be as described in U.S. Patent Publication No. 2018/0071820 entitled “Reversible Binders For Use In Binder Jetting Additive Manufacturing Techniques” and assigned to General Electric Corporation, Schenectady, N.Y. However, it should be understood that other binder materials are contemplated and possible, including combinations of various binder materials.
Referring initially to
Referring now to
In embodiments, the recoat advance rate may vary as the recoat head 140 is traversed over the working axis 116 of the apparatus 100 in the direction indicated by arrow 302. For example, the recoat advance rate may comprise an initial recoat advance rate prior to traversing over the supply platform 130 from the recoat home position 148 and a distribution advance rate as the recoat head 140 traverses over the supply platform 130 and the build platform 120. In embodiments, the recoat advance rate may be different (e.g., faster) between the supply platform 130 and the build platform 120. In embodiments, the distribution advance rate may be less than the initial recoat advance rate. This may promote uniformity in the layer of build material 400 distributed on the build platform 120 from the supply platform 130 and reduce defects in the object.
In embodiments where the recoat head 140 comprises an energy source as described herein with respect to
In embodiments where the recoat head 140 comprises at least one sensor as described herein with respect to
Referring now to
In the embodiments described herein, the recoat head 140 and the recoat head actuator 144 have a recoat cycle time TRH that is the elapsed time from when the recoat head 140 leaves the recoat home position 148 to when the recoat head 140 returns to the recoat home position 148. In the embodiments described herein, the platform cycle time TSP occurs within the recoat cycle time TRH.
Still referring to
In embodiments, the print advance rate may vary as the print head 150 is traversed over the working axis 116 of the apparatus 100 in the direction indicated by arrow 306. For example, the print advance rate may comprise an initial print advance rate prior to traversing over the build platform 120 from the print home position 158 and a deposition advance rate as the print head 150 traverses over the build platform 120. In embodiments, the deposition advance rate may be less than the initial print advance rate. This promotes precision in the deposition of the binder material 500 on the build platform 120.
As the print head 150 traverses over the build platform 120 in the direction indicated by arrow 306, the control system 200 sends a signal to the print head 150 causing the print head 150 to deposit a layer of binder material 500 in a predetermined pattern on the layer of build material 400 positioned on the build platform 120, as depicted in
While the binder material 500 has been described as being deposited in two portions which at least partially overlap, it should be understood that other embodiments are contemplated and possible. For example, the binder material 500 may be deposited by the print head 150 in a single pass, such as when the binder material 500 is deposited on the layer of build material 400 as the print head 150 traverses the working axis 116 (
Referring now to
In the embodiments described herein, the print head 150 and the print head actuator 154 have a print cycle time TPH that is the elapsed time from when the print head 150 leaves the print home position 158 to when the print head 150 returns to the print home position 158.
Still referring to
Still referring to
As depicted in
The build platform cycle time TBP and supply platform cycle time TSP may completely overlap with the print cycle time TPH and/or the recoat cycle time TRH and, as such, the build platform cycle time TBP and supply platform cycle time TSP do not contribute to the overall build cycle time TBC. Further, because at least portions of the cleaning station cycle time TCS, the print cycle time TPH, and the recoat cycle time TRH overlap with one another, the overall build cycle time TBC is less than the sum of the cleaning station cycle time TCS, the print cycle time TPH, and the recoat cycle time TRH. In embodiments, the overall build cycle time TBC is less than the sum of the print cycle time TPH and the recoat cycle time TRH, such as when at least a portion of the cleaning station cycle time TCS overlaps with the print cycle time TPH and the entire cleaning station cycle time TCS overlaps with the recoat cycle time TRH.
The reduction in the duration of the overall build cycle time TBC to less than the sum of the individual print, recoat, and cleaning cycle times is facilitated by the stacked configuration of the actuators 144, 154 which, in turn, allows the recoat head 140 and the print head 150 to move on the working axis 116 of the additive manufacturing apparatus 100 at the same time.
As described with respect to
Accordingly, the control system 200 may generate and control the motion of the recoat head 140, the print head 150, and the process accessory 190 (when included) to maintain a minimum separation distance over the course of the build cycle. Generally, it is beneficial that the minimum separation distance be as small as possible while still ensuring that collisions between the print head 150 and the recoat head 140 are avoided over the course of the build cycle. This way, efficiency benefits of simultaneous actuation of the print head 150 and the recoat head 140 are fully realized.
Referring now to
In a step 702, a minimum separation distance between the print head 150 and the recoat head 140 is determined. In embodiments, the minimum separation distance has two separate components: a collision distance and a velocity-based component. The collision distance may correspond to position measurements of the print head 150 and the recoat head 140 (e.g., measured via linear encoders associated with the print head actuator 154 and recoat head actuator 144, respectively) when the print head 150 contacts the recoat head 140. For example, prior to the build cycle, the print head 150 may be brought into contact with the recoat head 140 and position measurements taken via the linear encoders of the print head actuator 154 and recoat head actuator 144 may be used to determine a difference between a print head position and a recoat head position when the print head 150 is brought into contact with the recoat head 140 to determine the collision distance.
In embodiments, the velocity-based component of the minimum separation distance is a single value calculated based on the velocities at which the print head 150 and the recoat head 140 travel during the build cycle. For example, in embodiments, the velocity-based component accounts for maximum process velocities of the print head 150 and the recoat head 140 during the build cycle. The maximum process velocities of the print head 150 and the recoat head 140 may be added to one another to obtain a maximum relative velocity to account for situations in which the print head 150 and the recoat head 140 are moving towards one another. Once the maximum relative velocity is determined, the velocity-based component of the minimum separation distance may be determined based on the deceleration capabilities of the print head actuator 154 and the recoat head actuator 144. For example, if the print head actuator 154 is capable of a first deceleration rate and the recoat head actuator 144 is capable of a second deceleration rate, the smaller of the first deceleration rate and the second deceleration rate may be used to compute the velocity-based component of the minimum separation distance. The velocity-based component may then be added to the collision distance to determine the minimum separation distance. Such an approach beneficially avoids collisions between the print head 150 and the recoat head 140 while requiring minimum calculation.
In embodiments, a plurality of minimum separation distances are used throughout the build cycle. For example, in embodiments, the control system 200 calculates a real-time minimum separation distance during the build cycle based on the velocities at which the print head 150 and the recoat head 140 are traveling (e.g., determined via position measurements of the linear encoders of the print head actuator 154 and the recoat head actuator 144). Such an approach beneficially enables the control system 200 to detect faults in the motion of the print head 150 and the recoat head 140 (e.g., associated with unexpectedly high velocities and accelerations). Additionally, by taking the actual velocities of the print head 150 and the recoat head 140 into account, the real-time minimum separation distance may provide for smaller minimum separation distances than the maximum velocity-based approach described herein, leading to a more efficient build cycle.
In a step 704, the control system 200 determines cycle timing and motion profiles for the print head 150 and the recoat head 140 during a build cycle based on the minimum separation distance. In embodiments, in addition to the minimum separation distance determined at the step 702, the control system 200 relies on any combination of the following parameters to pre-calculate motion profiles and cycle timing for the print head 150 and the recoat head 140: the recoat home position 148, positions of the recoat head 140 at ends of the supply platform 130, positions of the recoat head 140 at ends of the build platform 120, a velocity of the recoat head 140 over the supply platform 130, a velocity of the recoat head 140 over the build platform 120, acceleration rates of the recoat head 140, the print home position 158, the position of the print head 150 after passing over the build platform 120, a print head 150 velocity over the build platform 120, and acceleration rates of the print head 150. For example, the control system 200 may determine timings during the build cycle at which the print head 150 and/or the recoat head 140 are at various positions to maintain the minimum separation distance based on the velocities at which the print head 150 and recoat head 140 are traveling during various portions of the build cycle. In other words, the motion profiles for each of the print head 150 and the recoat head 140 are calculated such that the print head 150 is never closer to the recoat head 140 than the minimum separation distance to ensure collision avoidance.
Referring now to
In a step 708, the print head 150 is homed on the print motion axis 156 and the recoat head 140 is homed on the recoat motion axis 146. For example, after the additive manufacturing apparatus 100 is powered on and a build job is initiated, the control system 200 may provide homing control signals to the print head actuator 154 and the recoat head actuator 144 to cause the print head 150 to travel to the print home position 158 and the recoat head 140 to travel to the recoat home position 148. In embodiments, once the print head 150 and the recoat head 140 are homed, the control system 200 normalizes position measurements taken by linear encoders of the print head actuator 154 and the recoat head actuator 144 to set motion profiles for the print head 150 and the recoat head 140 (e.g., the motion profiles determined via the control system 200 during the method 700 described herein). After the encoder measurements are normalized, the control system 200 may initiate a build cycle.
In a step 710, during the print cycle (e.g., during motion of the print head 150 and the recoat head 140), the control system 200 continuously monitors positions of the print head 150 and the recoat head 140. For example, in embodiments, the control system 200 monitors the positions of the print head 150 and the recoat head 140 via the linear encoders of the print head actuator 154 and the recoat head actuator 144. In embodiments, the actuator assembly 102 may include additional location detectors (e.g., proximity sensors) through which the control system 200 monitors the positions of the print head 150 and the recoat head 140. Using the real-time positioning of the print head 150 and the recoat head 140, during a step 712, the control system 200 determines whether the print head 150 and the recoat head 140 are travelling towards one another creating a risk of a collision. If the print head 150 and the recoat head 140 are travelling towards one another, in a step 714, the control system 200 determines if the print head 150 and the recoat head 140 are closer than a minimum separation distance (e.g., the minimum separation distance calculated via performance of the method 700 described herein). If the print head 150 and the recoat head 140 are closer than the minimum separation distance, in a step 716, the control system 200 sets a collision prevention fault and aborts the build cycle. For example, if the print head 150 and the recoat head 140 are closer than the minimum separation distance, the control system 200 may provide abort signals to the print head actuator 154 and the recoat head actuator 144 to cause the print head 150 and the recoat head 160 to return to the print home position 158 and the recoat home position 148, respectively.
In embodiments, in addition to continuously monitoring the positioning of the print head 150 and the recoat head 140 during the build cycle via the linear encoders of the print head actuator 154 and the recoat head actuator 144, the relative position of the print head 150 and the recoat head 140 may also be monitored via a working axis proximity sensor (not depicted). For example, various embodiments may incorporate a capacitive proximity sensor, a photoelectric sensor, an inductive proximity sensor, or the like coupled to at least one of the print head 150 and the recoat head 140. In embodiments, the working axis proximity sensor is used as a final collision prevention check (e.g., in addition to the real-time positions determined via the linear encoders of the print head actuator 154 and the recoat head actuator 144). For example, if the working axis proximity sensor generates a signal provided to the control system 200 that indicates that the print head 150 and the recoat head are separated by less than the minimum separation distance, the control system 200 may set a collision prevention fault. Thus, the working axis proximity sensor may serve as a final system check to avoid collisions.
Based on the foregoing, it should be understood that the actuator assemblies for additive manufacturing apparatuses described herein may be implemented to reduce the overall build cycle time of an additive manufacturing apparatus, thereby improving the manufacturing through-put of the additive manufacturing apparatus. In particular, the actuator assemblies include individual actuators, such as print head actuators and recoat head actuators, which are arranged in a stacked configuration. This allows the print head and the recoat head operatively associated with each actuator to move along the working axis of the additive manufacturing apparatus at the same time, in the same or different directions at the same or different speeds, which, in turn, allows the individual cycle times associated with each of the print head and the recoat head to overlap while maintaining the print quality, thereby reducing the overall build cycle time of the additive manufacturing apparatus to less than the sum of the individual cycle times.
While
Referring to
The build material hopper 360 may include an electrically actuated valve (not depicted) to release build material 400 onto the build platform 120 as the build material hopper 360 traverses over the build platform 120. In embodiments, the valve may be communicatively coupled to the control system 200 (
The embodiment of the additive manufacturing apparatus 101 depicted in
Another alternative embodiment of an additive manufacturing apparatus 105 is schematically depicted in
In this embodiment, the build material hopper 360 may include an electrically actuated valve (not depicted) to release build material 400 onto the build platform 120. In embodiments, the valve may be communicatively coupled to the control system 200 (
While
The embodiment of the additive manufacturing apparatus 105 depicted in
While
Referring to
In the embodiments described herein, the recoat head actuator 406 and the print head actuator 408 are coupled to the support 404. The recoat head actuator 144 is bi-directionally actuatable along a recoat motion axis 146 and the print head actuator 154 is bi-directionally actuatable along a print motion axis 156. That is, the recoat motion axis 146 and the print motion axis 156 define the axes along which the recoat head actuator 144 and the print head actuator 154 are actuatable, respectively. In embodiments, the recoat head actuator 144 and the print head actuator 154 are bi-directionally actuatable independent of one another. The recoat motion axis 146 and the print motion axis 156 extend in a horizontal direction and are parallel with the working axis 116 (
In the embodiments described herein, the recoat head actuator 144 and the print head actuator 154 may be, for example and without limitation, mechanical actuators, electro-mechanical actuators, pneumatic actuators, hydraulic actuators, or any other actuator suitable for providing linear motion. Suitable actuators may include, without limitation, worm drive actuators, ball screw actuators, pneumatic pistons, hydraulic pistons, electro-mechanical linear actuators, or the like. In embodiments, the recoat head actuator 144 and the print head actuator 154 are linear actuators similar to the PRO225LM Mechanical Bearing, Linear Motor Stage manufactured by Aerotech® Inc. of Pittsburgh, Pa. Alternatively, the recoat head actuator 144 and the print head actuator 154 may be linear actuators such as the Yamaha MF75D Linear Motor Single Axis Robot.
For example, the actuator assembly 402 may comprise a guide 410 affixed to the support 404 of the rail 180. The recoat head actuator 144 and the print head actuator 154 may be moveably coupled to the rail 180 such that the recoat head actuator 144 and the print head actuator 154 can independently traverse a length of the guide 410. In embodiments, the motive force traversing the recoat head actuator 144 and the print head actuator 154 is supplied by direct-drive linear motors, such as brushless servomotors, for example.
In embodiments, the recoat head actuator 144, the print head actuator 154, and the guide 410 may be a cohesive sub-system that is affixed to the rail 180, such as when the guide 410, the recoat head actuator 144 and the print head actuator 154 are similar to the PRO225LM Mechanical Bearing, Linear Motor Stage or the Yamaha MF75D Linear Motor Single Axis Robot, for example. However, it should be understood that other embodiments are contemplated and possible, such as embodiments where the recoat head actuator 144 and the print head actuator 154 comprise multiple components that are individually assembled onto the rail 180 to form the recoat head actuator 144 and the print head actuator 154, respectively.
Still referring to
In embodiments, the recoat head 140 may be pivotally coupled to the recoat head actuator 144. For example and without limitation, in the embodiment of the actuator assembly 402 depicted in
Still referring to
In embodiments, the print head 150 may be pivotally coupled to the print head actuator 154. For example and without limitation, in the embodiment of the actuator assembly 402 depicted in
As noted above, in embodiments described herein the recoat head 140 and the print head 150 are both located on the working axis 116 of the apparatus 100. As such, the movements of the recoat head 140 and the print head 150 on the working axis 116 occur along the same axis and are thus co-linear. With this configuration, the recoat head 140 and the print head 150 may occupy the same space (or portions of the same space) along the working axis 116 of the apparatus 100 at different times during a single build cycle. The recoat head 140 and the print head 150 may be moved along the working axis 116 of the apparatus 100 simultaneously in a coordinated fashion, in the same direction and/or in opposing directions, at the same speeds or different speeds. This, in turn, allows for individual steps of the additive manufacturing process, such as the distributing step (also referred to herein as the recoating step), the depositing step (also referred to herein as the printing step), the curing (or heating) step, and/or the cleaning step to be performed with overlapping cycle times. For example, the distributing step may be initiated while the cleaning step is being completed; the depositing step may be initiated while the distributing step in completed; and/or the cleaning step may be initiated while the distributing step is being completed. This may reduce the overall cycle time of the additive manufacturing apparatus 100 to less than the sum of the distributing cycle time (also referred to herein as the recoat cycle time), the depositing cycle time (also referred to herein as the print cycle time), and/or the cleaning cycle time.
While
The embodiment of the actuator assembly 402 depicted in
Various configurations of additive manufacturing apparatuses with actuator assemblies are described below with specific reference to
Referring now to
Referring now to
Referring now to
Referring now to
In this embodiment, the cleaning station 110, the build receptacle 124, and the supply receptacle 134 are arranged along the working axis 116 of the apparatus 504 with the build receptacle 124 positioned between the cleaning station 110 and the supply receptacle 134. The second build receptacle 124A and the second supply receptacle 134A are arranged along the working axis 116 of the apparatus 504 with the second build receptacle 124A positioned between the cleaning station 110 and the second supply receptacle 134A. The build receptacle 124 and the supply receptacle 134 are located on a side of the cleaning station 110 opposite the second build receptacle 124A and the second supply receptacle 134A.
The actuator assembly 102A is constructed to facilitate independent control of the recoat head 140, the recoat head 140A, the print head 150, and the second print head 150A along the working axis 116 of the apparatus 504. For example, the actuator assembly 102A facilitates traversing the print head 150 along the working axis 116 from a print home position 158 co-located with the cleaning station 110, over the build receptacle 124 and back again. The actuator assembly 102A also facilitates traversing the recoat head 140 along the working axis 116 from a recoat home position 148, over the supply receptacle 134, over the build receptacle 124 and back again. The actuator assembly 102A also facilitates traversing the print head 150 along the working axis 116 from the print home position 158 co-located with the cleaning station 110, over the second build receptacle 124A and back again. The actuator assembly 102A also facilitates traversing the second recoat head 140A along the working axis 116 from a second recoat home position 148A, over the second supply receptacle 134A, over the second build receptacle 124A and back again.
The actuator assembly 102A of this embodiment allows for the recoat head 140, the second recoat head 140A, and the print head 150 to independently traverse the working axis 116 of the apparatus 504 in the same direction and/or in opposite directions and for the recoat head 140, the second recoat head 140A, and the print head 150 to traverse the working axis of the apparatus 504 at different speeds and/or the same speed. Independent actuation and control of the recoat head 140, the second recoat head 140A and the print head 150, in turn, allows for at least some steps of the additive manufacturing process to be performed simultaneously thereby reducing the overall cycle time of the additive manufacturing process to less than the sum of the cycle time for each individual step.
Moreover, including a second recoat head 140A on the actuator assembly, along with a second build receptacle 124A and a second supply receptacle 134A, may further maximize the working time of the print head 150, thereby increasing manufacturing throughput. Specifically, while the recoat head 140 is distributing build material from the supply receptacle 134 to the build receptacle 124, the print head 150 may be utilized to deposit binder material on build material in the second build receptacle 124A. Likewise, while the second recoat head 140A is distributing build material from the second supply receptacle 134A to the second build receptacle 124A, the print head 150 may be utilized to deposit binder material on build material in the build receptacle 124.
While
Referring now to
Still referring to
As described herein, the housing 910 comprises a sidewall 912 at least partially enclosing a build chamber 914. The phrase “at least partially enclosing,” as used herein, means that the sidewall 912 bounds the build chamber 914 on at least one side. For example, the sidewall 912 bounds at least the vertical sides of the build chamber 914 (i.e., the sides of the build chamber extending in the +/−Z direction of the coordinate axes depicted in the figures) in the embodiment depicted in
The housing 910 and sidewall 912 of the build receptacle 124A may be constructed of, for example and without limitation, a metal or a metallic alloy. As non-limiting examples, the metal or metallic alloy may comprise aluminum or an aluminum alloy, steel, copper or a copper alloy, nickel or a nickel alloy, bronze, or combinations thereof.
Referring now to
In embodiments, the plurality of heating elements 920 may be disposed on an exterior surface 913 of the sidewall 912, as depicted in
In embodiments, the build platform 120 may be constructed to supply heat and/or supplemental heating to the build chamber 914. For example, in embodiments, the build platform 120 may comprise channels or bores in the thickness of the build platform 120 and heating elements 920 may be disposed within the channels or bores, as depicted in
In embodiments, a plurality of heating elements 920 may optionally be disposed on a top surface 814 of a heating platen 810 of the lift system 800, disposed within the thickness of the heating platen 810 as depicted in
In the embodiments described herein, the heating elements 920 may have one or more form factors. For example and without limitation, the plurality of heating elements 920 may be resistance heaters, cartridge heaters, heating cables, heating tape, or various combinations thereof.
Referring still to
In embodiments, the build receptacle 124A may further comprise a plurality of temperature sensors 922 arranged around the build chamber 914. In embodiments, the temperature sensors 922 may be disposed on the exterior surface 913 of the sidewall 912. Alternatively, the temperature sensors 922 may be disposed within the sidewall 912. In embodiments where the build receptacle 124A comprises heating elements 920 disposed on or in the build platform 120, the build receptacle 124A may further comprise temperature sensors 922 on or in the build platform 120. In embodiments where the build receptacle 124A comprises heating elements 920 disposed on or in the heating platen 810, the build receptacle 124A may further comprise temperature sensors 922 on or in the heating platen 810.
In embodiments, the temperature sensors 922 may be coupled to individual ones of the plurality of heating elements 920. In embodiments, two temperature sensors 922 may be coupled to individual ones of the plurality of heating elements 920. In such embodiments, the temperature sensors may be positioned such that the diameter (or width) of the build chamber 914 is positioned between the temperature sensors 922.
As a non-limiting example, the plurality of temperature sensors 922 may include resistance temperature detectors, thermocouples, thermopiles or the like. In embodiments, the temperature sensors 922 may detect the heat output of the plurality of heating elements 920, may detect the temperature of the build chamber 914, or both.
Referring now to
In embodiments, the seal 930 may include a core portion 932 and an enveloping portion 934. In embodiments, the enveloping portion 934 at least partially encloses the core portion 932. In embodiments, the core portion 932 may include polytetrafluoroethylene and the enveloping portion 934 may include a fibrous material. For example, in embodiments, the core portion 932 may comprise a braided polytetrafluoroethylene packing seal. However, it should be understood that other materials may be used for the core portion 932 including, without limitation, Viton™ seals or the like. In embodiments, the fibrous material of the enveloping portion 934 may be a wool felt seal. However, it should be understood that other materials may be used for the enveloping portion 934 including, without limitation, felt seals constructed of other fibrous material or the like.
In embodiments, the build platform 120 may comprise a seal seat 936 formed in an edge of the build platform 120. The seal 930 may be positioned in the seal seat 936 such that the seal 930 is disposed between the build platform 120 and the interior surface 915 of the sidewall 912. In embodiments, the apparatus 100 further includes a seal frame 938 enclosing at least a portion of the seal seat 936. In embodiments, the seal frame 938 may be recessed in a top surface 974 of the build platform 120 (as depicted in
In alternative embodiments (not depicted), the build platform 120 may comprise a groove in the perimeter of the build platform 120 between the top surface 974 and the bottom surface 976 of the build platform 120. In this embodiment, the seal 930 may be disposed in the groove such that the seal is positioned between the build platform 120 and the interior surface 915 of the sidewall 912 of the build receptacle 124A.
Referring now to
Referring again to
Referring to
In embodiments, each lift point of the plurality of lift points 942 may comprise a handle extending from the flange 940, the sidewall 912, or both. For example, and without limitation, the handle may be an inverted U-shaped member attached to the flange 940 or an inverted L-shaped member attached to the flange 940. Alternatively, the handle may be a C-shaped member attached to the sidewall 912. Alternatively, each lift point of the plurality of lift points 942 comprises a lift flange extending from the sidewall 912. For example, and without limitation, the lift flange may comprise a rod extending perpendicularly from the sidewall 912. Alternatively, the lift flange may comprise an L-shaped member attached to the sidewall 912.
Referring again to
Referring now to
While
Still referring to
The housing 910 of the build receptacle 124A may further include a plurality of retention tabs 980, as depicted in
Referring to
In embodiments, the electrical connectors 924 may also facilitate portability of the build receptacle 124A. For example, the electrical connectors 924 may be connected to a power source regardless of whether the build receptacle 124A is within the apparatus 100. In embodiments, the electrical connectors 924 may be connected to a power source when the build receptacle 124A is within the apparatus 100, when the build receptacle 124A is at a curing station as previously described, or when the build receptacle 124A is at a depowdering station as previously described.
Referring to
The heating platen 810 is thermally coupled to the build platform 120, such as by proximity coupling, when the lift system 800 is coupled to the build platform 120 with the connectors 990 previous described (
In the embodiment shown in
While
In the embodiments described herein, the lift system 800 may further comprise a plurality of vertical guides 820 coupled to the heating platen 810. The plurality of vertical guides 820 extend in a vertical direction (i.e., a direction parallel to the +/−Z direction of the coordinate axes in the figures) and are spaced apart from one another in a horizontal direction (i.e., a direction parallel to the +/−X direction of the coordinate axes depicted in the figures). The lift system 800 may include a single vertical guide (not depicted), or multiple vertical guides 820, as depicted in
In embodiments, the lift system 800 may include sensors for determining the location of the heating platen 810, the build platform 120, or both. For example, the lift system 800 may include a heating platen position sensor 840 for detecting a vertical position of the heating platen 810. The heating platen position sensor 840 may be positioned proximate to a lower end 860 of the lift system 800 and, in some embodiments, includes a limit switch. In embodiments, the limit switch may comprise a capacitive limit switch, an inductive limit switch, a photoelectric limit switch, a mechanical limit switch, or combinations thereof. The heating platen position sensor 840 may be communicatively coupled to the control system 200 such that the control system 200 receives electrical signals indicative of the position of the heating platen 810. The control system 200 may utilize these signals to control positioning of the heating platen 810 (and hence the build platform 120 attached to the heating platen 810) within the build receptacle 124A.
The lift system 800 may further include a build platform position sensor 850 for detecting a vertical position of the build platform 120. In some embodiments, the build platform position sensor 850 may include an inductive limit switch. In embodiments, the limit switch may comprise a capacitive limit switch, an inductive limit switch, a photoelectric limit switch, a mechanical limit switch, or combinations thereof. The build platform position sensor 850 may be communicatively coupled to the control system 200 such that the control system 200 receives electrical signals indicative of the position of the build platform 120. The control system 200 may utilize these signals to control positioning of the build platform 120 within the build receptacle 124A.
Referring now to
In embodiments, as shown in
When the build platform position sensor 850 senses the sensor flag 1624, the control system 200 may release the connectors 990 from a pneumatically activated position (as shown in
The build platform 120 may rest at the bottom 970 of the build chamber 914 (as shown in
Although the lift system 800 is described herein in the context of the build receptacle 124A, it should be understood that the additive manufacturing apparatus 100 may include a similar lift system 800 removably coupled to the supply receptacle 134 (
Referring to
In the embodiments described herein, the processor 202 of the control system 200 is configured to provide control signals to (and thereby actuate) the build platform actuator 122, the plurality of heating elements 920, and the temperature sensors 922. The control system 200 may also be configured to receive signals from the plurality of heating elements 920, the temperature sensors 922, the heating platen position sensor 840, and the build platform position sensor 850 and, based on these signals, actuate either the build platform actuator 122 and/or the plurality of heating elements 920.
In embodiments, the heating platen position sensor 840 may be communicatively coupled to the control system 200 as described herein. The heating platen position sensor 840 may provide a feedback signal to the control system 200 to cease actuating the lift system 800. The heating platen position sensor 840 may detect the position of the heating platen 810 to ensure the heating platen 810 and the build platform 120 are not actuated below a lower end 860 of the lift system 800, to avoid damage to the apparatus 100.
In embodiments, the build platform position sensor 850 may be communicatively coupled to a control system 200 as described herein. The build platform position sensor 850 may provide a feedback signal to the control system 200 to cease actuating the lift system 800. The build platform position sensor 850 may detect the position of the build platform 120 to ensure the build platform 120 and the heating platen 810 are not actuated below a lower limit proximate a lower end 860 of the lift system 800, to avoid damage to the apparatus 100.
Referring to
In embodiments, the plurality of heating elements 920 positioned around the build chamber 914 may form two distinct heating zones 926, specifically heating zone 926A and heating zone 926B (as depicted in
In embodiments, following the logic described previously in regards to two distinct heating zones 926 (926A and 926B), it is contemplated that the plurality of heating elements 920 positioned on the build receptacle 124A may form three or more distinct heating zones 926 (926A, 926B, 926C, etc.). These distinct heating zones may form blocked groupings or alternating groupings.
The operation of the build receptacle 124A will now be described in further detail with specific reference to
Referring initially to
In
The deposition region 917 of the build chamber 914 may be pre-heated to a pre-heat temperature prior to deposition, and/or during deposition of the build material 400 and the binder material 500. For example, in some embodiments, the deposition region 917 of the build chamber 914 may be pre-heated to a pre-heat temperature prior to deposition of the build material 400 and the binder material 500. The deposition region 917 of the build chamber 914 may be pre-heated using any of the plurality of heating elements 920 previously described. In some embodiments, the pre-heating is achieved with the plurality of heating elements 920 positioned around the build chamber 914 and/or below the build platform 120.
As stated previously, the plurality of heating elements 920 may be arranged in heating zones wherein each heating zone is independently actuatable by the control system 200 (depicted in
If the pre-heat temperatures is too low, the binder material tends to seep into and diffuse into the powder material. If the pre-heat temperature is too high, the binder material may become too dry which, in turn, weakens the part. Accordingly, in the embodiments described herein, the pre-heat temperature may be less than or equal to 100° C., less than or equal to 90° C., less than or equal to 80° C., less than or equal to 75° C., less than or equal to 70° C., less than or equal to 65° C., less than or equal to 60° C., less than or equal to 55° C., less than or equal to 50° C., less than or equal to 40° C., or even less than or equal to 30° C. In some embodiments, the pre-heat temperature may range from 25° C. to 130° C., from 30° C. to 100° C., from 40° C. to 100° C., from 50° C. to 100° C., from 55° C. to 100° C., from 60° C. to 100° C., from 65° C. to 100° C., from 70° C. to 100° C., from 75° C. to 100° C., from 80° C. to 100° C., from 90° C. to 100° C., from 30° C. to 90° C., from 40° C. to 90° C., from 50° C. to 90° C., from 55° C. to 90° C., from 60° C. to 90° C., from 65° C. to 90° C., from 70° C. to 90° C., from 75° C. to 90° C., from 80° C. to 90° C., from 30° C. to 80° C., from 40° C. to 80° C., from 50° C. to 80° C., from 55° C. to 80° C., from 60° C. to 80° C., from 65° C. to 80° C., from 70° C. to 80° C., from 75° C. to 80° C., from 30° C. to 75° C., from 40° C. to 75° C., from 50° C. to 75° C., from 55° C. to 75° C., from 60° C. to 75° C., from 65° C. to 75° C., from 70° C. to 75° C., from 30° C. to 70° C., from 40° C. to 70° C., from 50° C. to 70° C., from 55° C. to 70° C., from 60° C. to 70° C., from 65° C. to 70° C., from 30° C. to 65° C., from 40° C. to 65° C., from 50° C. to 65° C., from 55° C. to 65° C., from 60° C. to 65° C., from 30° C. to 60° C., from 40° C. to 60° C., from 50° C. to 60° C., from 55° C. to 60° C., from 30° C. to 55° C., from 40° C. to 55° C., or from 50° C. to 55° C.
The aforementioned pre-heat temperatures may be used, for example, when the binder material is a water-based binder material. Accordingly, it should be understood that, for different binder materials (such as non-water-based binder materials) different pre-heat temperatures may be used.
After distributing a layer of build material 400 on the build platform 120 positioned within the build chamber 914 and then depositing a layer of binder material 500 on the layer of build material 400 as described previously, the position of the build platform 120 may be adjusted in the downward vertical direction, as depicted in
The curing region 918 of the build chamber 914 may be heated to a curing temperature to cure the portion of build material 400 and binder material 500 within the curing region 918 of the build chamber 914. In embodiments, the curing temperature may be greater than the pre-heat temperature. The curing region 918 of the build chamber 914 may be heated using any of the plurality of heating elements 920 previously described. In some embodiments, the heating is achieved with the plurality of heating elements 920 positioned around the build chamber 914 and/or below the build platform 120.
As stated previously, in embodiments, individual heating elements of the plurality of heating elements 920 that are positioned vertically above axis d may be part of a different heating zone than individual heating elements of the plurality of heating elements 920 that are positioned vertically below axis d. Therefore, individual heating elements of the plurality of heating elements 920 that are positioned vertically below axis d may be actuated to heat the curing region 918 of the build chamber 914 to the curing temperature, whereas individual heating elements of the plurality of heating elements 920 that are positioned vertically above axis d may not be actuated, or may be actuated to pre-heat the deposition region 917 of the build chamber 914 to a pre-heat temperature.
The curing temperature (i.e., the temperature to which the curing region of the 918 of the build chamber 914 is heated) may range from 40° C. to 300° C., from 50° C. to 300° C., from 70° C. to 300° C., from 100° C. to 300° C., from 130° C. to 300° C., from 150° C. to 300° C., from 175° C. to 300° C., from 200° C. to 300° C., from 225° C. to 300° C., from 250° C. to 300° C., from 40° C. to 250° C., from 50° C. to 250° C., from 70° C. to 250° C., from 100° C. to 250° C., from 130° C. to 250° C., from 150° C. to 250° C., from 175° C. to 250° C., from 200° C. to 250° C., from 225° C. to 250° C., from 40° C. to 225° C., from 50° C. to 225° C., from 70° C. to 225° C., from 100° C. to 225° C., from 130° C. to 225° C., from 150° C. to 225° C., from 175° C. to 225° C., from 200° C. to 225° C., from 40° C. to 200° C., from 50° C. to 200° C., from 70° C. to 200° C., from 100° C. to 200° C., from 130° C. to 200° C., from 150° C. to 200° C., from 175° C. to 200° C., from 40° C. to 175° C., from 50° C. to 175° C., from 70° C. to 175° C., from 100° C. to 175° C., from 130° C. to 175° C., from 150° C. to 175° C., from 40° C. to 150° C., from 50° C. to 150° C., from 70° C. to 150° C., from 100° C. to 150° C., from 130° C. to 150° C., from 40° C. to 130° C., from 50° C. to 130° C., from 70° C. to 130° C., from 100° C. to 130° C., from 40° C. to 100° C., from 50° C. to 100° C., or from 70° C. to 100° C.
Referring to
Referring now to
In embodiments, the temperature of the curing region 918 may be detected during the thermal curing process. The control system, as previously described, may detect the temperature of the curing region 918 of the build chamber 914 through the use of temperature sensors. In some embodiments, the curing temperature of the curing region 918 of the build chamber 914 may be adjusted based on the detected temperature of the curing region 918. Without being bound by theory, the curing temperature of the curing region 918 of the build chamber 914 may be adjusted depending on the thermal conductivity of the build platform 120, the thermal conductivity of the sidewall 912 of the housing 910, and/or the thermal conductivity of the heating platen 810.
Further, in some embodiments, the temperature within the curing region 918 may be adjusted as a build operation progresses. For example, the temperature gradient between the axis d and the bottom 970 of the build chamber 914 may be reduced as the build operation progresses such that the temperature within the build chamber 914 is the same at the bottom 970 of the build chamber 914 as at the axis d.
As noted herein, the build receptacle 124A and methods for using the build receptacle 124A may be used in conjunction with one or more of the embodiments of the additive manufacturing apparatuses described herein, including the method of operating an additive manufacturing apparatus as described herein with respect to
The foregoing description includes various embodiments of components of additive manufacturing apparatuses and methods for using the same. It should be understood that various combinations of these components may be included in additive manufacturing apparatuses and arranged in (or coupled to) a support chassis.
Referring to
Pairs of vertical support members 1006a, 1006b extend between and are coupled to the pair of lower horizontal support members 1003a, 1003b and the pair of upper horizontal support members 1004a, 1004b, as depicted in
Still referring to
In the embodiments described herein, the pair of vertical support members 1006a, 1006b positioned between the print bay 1050 and the build bay 1020 and the pair of vertical support members 1006a, 1006b positioned between the print bay 1050 and the build bay 1020 each comprise a bulkhead 1007. Referring to
Referring now to
Referring again to
In embodiments, the low voltage supply lines 1026 are directed through cable trays 1008a, 1008c at the front 1011 of the support chassis 1002 and the high voltage supply lines 1028 are directed through cable trays 1008b, 1008d at the back 1013 of the support chassis 1002, as depicted in
In embodiments, the cable trays 1008c, 1008d extend through the lower compartments 1024, 1044, 1054 of the build bay 1020, material supply bay 1040, and print bay 1050, respectively. In these embodiments, the cable trays 1008c, 1008d may pass through the bulkhead 1007 between the build bay 1020 and the material supply bay 1040 and through the bulkhead 1007 between the build bay 1020 and the print bay 1050. To facilitate sealing the portions of the cable trays 1008c, 1008d that pass through the bulkheads 1007, the cable trays 1008c, 1008d may further comprise sealing glands 1030 which form a seal between the cable trays 1008c, 1008d, the bulkheads 1007 and any lines (or other conduits) passing through the bulkheads 1007 in the cable trays 1008c, 1008d.
Still referring to
Referring again to
In embodiments, the lower compartment 1024 of the build bay 1020 comprises a build receptacle 124. In these embodiments, the working surface 1010 of the support chassis 1002 comprises an opening for receiving the build receptacle 124 such that the build receptacle 124 is removably positioned in the working surface 1010 and the lower compartment 1024 of the build bay 1020. This allows for the build receptacle 124 (and the contents thereof) to be removed from the additive manufacturing apparatus 100 after a build operation is completed and an empty build receptacle 124 to be installed in the working surface 1010 and lower compartment 1024 of the build bay 1020. The lower compartment of the build bay 1020 may further comprise a lift system 800 for raising and lowering the build platform 120 of the build receptacle 124, as described herein.
In embodiments, the lower compartment 1024 of the build bay 1020 may further comprise a build bay temperature sensor 1032 for detecting the temperature of the lower compartment of the build bay 1020. The build bay temperature sensor 1032 may be, for example, and without limitation, a thermocouple, thermopile, or similar temperature sensor. The build bay temperature sensor 1032 may be coupled to the control system 200 and provides the control system 200 with a signal indicative of the temperature of the lower compartment 1024 of the build bay 1020. The control system 200 may use this signal to monitor the temperature the lower compartment 1024 of the build bay 1020 and provide a warning signal if an over-temperature (e.g., an overheating condition) condition is present. In embodiments, the control system 200 may take remedial actions to correct the over-temperature condition, such as by increasing the airflow through the lower compartment 1024 of the build bay 1020 to reduce the temperature.
In embodiments, the build bay 1020 may further comprise a build temperature sensor 1034 located in the upper compartment 1022 of the build bay 1020. The build temperature sensor 1034 is oriented to detect the temperature of the build material located on the build platform 120. The build temperature sensor 1034 may be, for example, and without limitation, an infrared temperatures sensor, such as an infrared camera, a pyrometer, or a similar temperature sensor. The build temperature sensor 1034 may be coupled to the control system 200 (as described in further detail herein) and provides the control system 200 with a signal indicative of the temperature of the build material (and binder material) located on the build platform 120. The control system 200 may use this signal to monitor the temperature of the build material and adjust the heating of the build material (and binder material) in the build receptacle 124 with the energy sources of the recoat head 140 and/or the heating elements 920 of the build receptacle 124, as described herein.
In embodiments, the build bay 1020 may further comprise a camera system 1036 located in the upper compartment 1022 of the build bay 1020. The camera system 1036 is oriented to collect an image of the build material located on the build platform 120. The camera system 1036 may be coupled to the control system 200 (as described in further detail herein) and provides the control system 200 with a signal indicative of the image of the surface of the build material (and binder material) located on the build platform 120. The control system 200 may use this signal to monitor the deposition of the build material on the build platform 120 and adjust the operation of the build platform 120 of the build receptacle 124, the operation of the supply platform 130 of the supply receptacle 134 and/or the operation of the recoat head 140 to obtain a layer of build material with the desired characteristics (e.g., surface uniformity, thickness, or the like). Alternatively or additionally, the control system 200 may use this signal to monitor the deposition of the binder material on the build platform 120 and adjust the operation of the print head to achieve deposition of the binder material with the desired characteristics (e.g., surface uniformity, pattern uniformity, pattern consistency, or the like).
In addition to the foregoing, in embodiments, at least one of the build bay 1020, the material supply bay 1040, and the print bay 1050 may further comprise an environmental sensor 1038 for detecting an air temperature or a humidity within the support chassis 1002. The environmental sensor 1038 may comprise, for example, and without limitation, a hygrometer and/or a temperature sensor. The environmental sensor 1038 may be coupled to the control system 200 (as described in further detail herein) and provides the control system 200 with a signal indicative of the temperature and or humidity within the support chassis 1002. The control system 200 may use this signal to monitor the temperature and/or humidity within the support chassis 1002 and provide a warning signal if either the temperature and/or humidity within the support chassis 1002 is outside of a predetermined range. In embodiments, the control system 200 may take remedial actions to correct the temperature and/or humidity, such as by adjusting the airflow through the support chassis 1002.
In some embodiments, the lower compartment 1044 of the material supply bay 1040 comprises a supply receptacle 134. In these embodiments, the working surface 1010 of the support chassis 1002 comprises an opening for receiving the supply receptacle 134 such that the supply receptacle 134 is removably positioned in the working surface 1010 and the lower compartment 1044 of the material supply bay 1040. In embodiments, this may allow for an empty supply receptacle 134 to be extracted from the additive manufacturing apparatus 100 after a build operation is completed and full build receptacle 124 to be installed in the working surface 1010 and lower compartment 1044 of the material supply bay 1040. The lower compartment 1044 of the build bay 1020 may further comprise a lift system 800 for raising and lowering the supply platform 130 of the supply receptacle 134, as described herein.
While
Referring now to
For example, the upper compartment 1022 of the build bay 1020 comprises an upper access panel 1064 hingedly coupled to the upper horizontal support member 1004a at the front 1011 of the additive manufacturing apparatus 100. The upper access panel 1064 may comprise a latch 1066 for latching the upper access panel 1064 to the working surface 1010 or a vertical support member 1006a. In embodiments, seals (not depicted) may be disposed between the upper access panel 1064 and the upper horizontal support member 1004a, the vertical support members 1006a, and the working surface 1010 to facilitate sealing the upper access panel 1064 to the support chassis 1002 when the upper access panel 1064 is in a closed position.
Further, the lower compartment 1024 of the build bay 1020 comprises a lower access panel 1068 hingedly coupled to the vertical support member 1006a at the front 1011 of the additive manufacturing apparatus 100, between the build bay 1020 and the material supply bay 1040 or between the build bay 1020 and the print bay 1050. The lower access panel 1068 may comprise a latch 1066 for latching the lower access panel 1068 to the working surface 1010 or a vertical support member 1006a. In embodiments, seals (not depicted) may be disposed between the lower access panel 1068 and the lower horizontal support member 1003a, the vertical support members 1006a, and the working surface 1010 to facilitate sealing the lower access panel 1068 to the support chassis 1002 when the lower access panel 1068 is in a closed position. In embodiments, the lower compartment 1024 of the build bay 1020 may comprise air inlets 1074 proximate the top of the compartment (i.e., proximate to but below the working surface 1010). In embodiments, the air inlets 1074 extend through the lower access panel 1068 of the build bay 1020.
Still referring to
Further, the lower compartment 1044 of the material supply bay 1040 comprises a lower access panel 1072 hingedly coupled to the vertical support member 1006a at the first end 1012 of the support chassis 1002 at the front 1011 of the additive manufacturing apparatus 100. The lower access panel 1072 may comprise a latch 1066 for latching the lower access panel 1072 to the working surface 1010 or a vertical support member 1006a. In embodiments, seals (not depicted) may be disposed between the lower access panel 1072 and the lower horizontal support member 1003a, the vertical support members 1006a, and the working surface 1010 to facilitate sealing the lower access panel 1072 to the support chassis 1002 when the lower access panel 1072 is in a closed position.
The upper compartment 1052 of the print bay 1050 comprises an upper access panel 1060 hingedly coupled to the upper horizontal support member 1004a at the front 1011 of the additive manufacturing apparatus 100. The upper access panel 1060 may comprise a latch 1066 for latching the upper access panel 1060 to the working surface 1010 or a vertical support member 1006a. In embodiments, seals (not depicted) may be disposed between the upper access panel 1060 and the upper horizontal support member 1004a, the vertical support members 1006a, and the working surface 1010 to facilitate sealing the upper access panel 1060 to the support chassis 1002 when the upper access panel 1060 is in a closed position.
Further, the lower compartment 1054 of the print bay 1050 comprises a lower access panel 1062 hingedly coupled to the vertical support member 1006a at the second end 1014 of the support chassis 1002 at the front 1011 of the additive manufacturing apparatus 100. The lower access panel 1062 may comprise a latch 1066 for latching the lower access panel 1062 to the working surface 1010 or a vertical support member 1006a. In embodiments, seals (not depicted) may be disposed between the lower access panel 1062 and the lower horizontal support member 1003a, the vertical support members 1006a, and the working surface 1010 to facilitate sealing the lower access panel 1062 to the support chassis 1002 when the lower access panel 1062 is in a closed position.
While
In the embodiment depicted in
Still referring to
In embodiments, the lower exhaust system 1090 is operated to draw air out of the build bay 1020, such as out of the lower compartment 1024 of the build bay 1020. In these embodiments, fresh air is drawn into the lower compartment 1024 through the air inlets 1074 and is exhausted from the lower compartment 1024 through the lower exhaust system 1090. The exhausted air passes through filter 1093 to remove particulates, such as particulates of build material, from the air. The air circulating through the lower compartment 1024 assists in preventing the buildup of heat in the lower compartment 1024 around the build receptacle 124. In addition, exhausting air through the lower exhaust system 1090 may aid in reducing particulates of build material in the air in the lower compartment 1024, thereby reducing the potential of fouling the components of the additive manufacturing apparatus 100. As noted hereinabove, the control system 200 may utilize the build bay temperature sensor 1032 to determine the temperature of the lower compartment 1024 and, based on the temperature, operate the exhaust fan 1092 of the lower exhaust system 1090 to maintain the temperature of the lower compartment 1024 within a predetermined range.
In embodiments, the additive manufacturing apparatus further comprises an upper exhaust system 1091 coupled to the top panel 1001 of the support chassis 1002. The upper exhaust system 1091 generally comprises an exhaust fan 1092 and, optionally, a filter 1093, such as a HEPA filter. The exhaust fan 1092 is communicatively coupled to the control system 200 that controls the speed of rotation of the fan and, therefore, the amount of air drawn through the fan per unit of time. The control system 200 may also control the direction of rotation of the fan so that air can either be drawn into the support chassis 1002 or expelled from the support chassis 1002.
In embodiments, the upper exhaust system 1091 is operated to draw air out of the volume enclosed by the support chassis 1002. The exhausted air passes through filter 1093 to remove particulates, such as particulates of build material, from the air. Exhausting air through the upper exhaust system 1091 may aid in regulating the temperature and/or humidity around the build platform 120. In addition, exhausting air through the upper exhaust system 1091 may aid in reducing particulates of build material in the air within the volume of the support chassis 1002, thereby reducing the potential of fouling the components of the additive manufacturing apparatus 100. As noted hereinabove, the control system 200 may utilize the environmental sensor 1038 to determine the temperature and/or humidity within the support chassis 1002 and, based on the temperature and/or humidity, operate the exhaust fan 1092 of the upper exhaust system 1091 to maintain the temperature and/or humidity within a predetermined range.
Referring now to
In embodiments, the recovery funnel 1082 is fluidly coupled to a vacuum system 1102. The vacuum system 1102 applies a negative pressure to the recovery funnel 1082 and the powder recovery slot 1080 that, in turn, aids in drawing build material through the powder recovery slot 1080 and the recovery funnel 1082. The vacuum system 1102 is coupled to a sieve system 1110 such that the vacuum system 1102 directs the recovered build material into the sieve system 1110. The sieve system 1110 screens the recovered build material, removing agglomerated build material, agglomerated binder material, or the like, such that the recovered build material can be reused in the additive manufacturing apparatus 100.
Still referring to
The sieve system 1110 may also be coupled to a de-powdering station 1150. As described herein, the de-powdering station 1150 comprises a lift system 800 to facilitate raising a build platform 120 of a build receptacle 124 during a de-powdering operation. In embodiments, the de-powdering station 1150 may also have electrical connections for power the heating elements of the build receptacle such as when the build receptacle is as described herein with respect to
Still referring to
While
Referring now to
In the embodiments described herein, the cleaning station 2110, the build platform 2120, and the supply platform 2130 are positioned in series along the working axis 2116 of the system 2100 between a print home position 2158 of the print head 2150 located proximate an end of the working axis 2116 in the −X direction, and a recoat home position 2148 of the recoat assembly 2200 located proximate an end of the working axis 2116 in the +X direction. That is, the print home position 2158 and the recoat home position 2148 are spaced apart from one another in a horizontal direction that is parallel to the +/−X axis of the coordinate axes depicted in the figures and the cleaning station 2110, the build area 2124, and the supply platform 2130 are positioned therebetween. In the embodiments described herein, the build area 2124 is positioned between the cleaning station 2110 and the supply platform 2130 along the working axis 2116 of the system 2100.
The cleaning station 2110 is positioned proximate one end of the working axis 2116 of the system 2100 and is co-located with the print home position 2158 where the print head 2150 is located or “parked” before and after depositing binder material 2050 on a layer of build material 2031 positioned on the build area 2124. The cleaning station 2110 may include one or more cleaning sections (not shown) to facilitate cleaning the print head 2150 between depositing operations. The cleaning sections may include, for example and without limitation, a soaking station containing a cleaning solution for dissolving excess binder material on the print head 2150, a wiping station for removing excess binder material from the print head 2150, a jetting station for purging binder material and cleaning solution from the print head 2150, a park station for maintaining moisture in the nozzles of the print head 2150, or various combinations thereof. The print head 2150 may be transitioned between the cleaning sections by the actuator assembly 2102.
While reference is made herein to additive manufacturing systems including a print head 2150 that dispenses a binder material 2050, it should be understood that recoat assemblies 2200 described herein may be utilized with other suitable additive powder-based additive manufacturing systems. For example, in some embodiments, instead of building objects with a cured binder material 2050 applied to build material 2031, in some embodiments, a laser or other energy source may be applied to the build material 2031 to fuse the build material 2031.
In the embodiment depicted in
The supply platform 2130 is coupled to a supply platform actuator 2132 to facilitate raising and lowering the supply platform 2130 relative to the working axis 2116 of the system 2100 in a vertical direction (i.e., a direction parallel to the +/−Z directions of the coordinate axes depicted in the figures). The supply platform actuator 2132 may be, for example and without limitation, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, or any other actuator suitable for imparting linear motion to the supply platform 2130 in a vertical direction. Suitable actuators may include, without limitation, a worm drive actuator, a ball screw actuator, a pneumatic piston, a hydraulic piston, an electro-mechanical linear actuator, or the like. The supply platform 2130 and supply platform actuator 2132 are positioned in a supply receptacle 2134 located below the working axis 2116 (i.e., in the −Z direction of the coordinate axes depicted in the figures) of the system 2100. During operation of the system 2100, the supply platform 2130 is raised relative to the supply receptacle 2134 and towards the working axis 2116 of the system 2100 by action of the supply platform actuator 2132 after a layer of build material 2031 is distributed from the supply platform 2130 to the build platform 2120, as will be described in further detail herein.
In embodiments, the actuator assembly 2102 generally includes a recoat assembly transverse actuator 2144, a print head actuator 2154, a first guide 2182, and a second guide 2184. The recoat assembly transverse actuator 2144 is operably coupled to the recoat assembly 2200 and is operable to move the recoat assembly 2200 relative to the build platform 2120 to dispense build material 2031 on the build platform 2120, as described in greater detail herein. The print head actuator 2154 is operably coupled to the print head 2150 and is operable to move the print head 2150 and is operable to move the print head 2150 relative to the build platform 2120 to dispense the binder material 2050 on the build platform 2120.
In the embodiments described herein, the first guide 2182 and the second guide 2184 extend in a horizontal direction (i.e., a direction parallel to the +/−X direction of the coordinate axes depicted in the figures) parallel to the working axis 2116 of the system 2100 and are spaced apart from one another in the vertical direction. When the actuator assembly 2102 is positioned over the cleaning station 2110, the build platform 2120, and the supply platform 2130 as depicted in
In one embodiment, such as the embodiment of the actuator assembly 2102 depicted in
In the embodiments described herein, the recoat assembly transverse actuator 2144 is coupled to one of the first guide 2182 and the second guide 2184 and the print head actuator 2154 is coupled to the other of the first guide 2182 and the second guide 2184 such that the recoat assembly transverse actuator 2144 and the print head actuator 2154 are arranged in a “stacked” configuration. For example, in the embodiment of the actuator assembly 2102 depicted in
In the embodiments described herein, the recoat assembly transverse actuator 2144 is bi-directionally actuatable along a recoat motion axis 2146 and the print head actuator 2154 is bi-directionally actuatable along a print motion axis 2156. That is, the recoat motion axis 2146 and the print motion axis 2156 define the axes along which the recoat assembly transverse actuator 2144 and the print head actuator 2154 are actuatable, respectively. The recoat motion axis 2146 and the print motion axis 2156 extend in a horizontal direction and are parallel with the working axis 2116 of the system 2100. In the embodiments described herein, the recoat motion axis 2146 and the print motion axis 2156 are parallel with one another and spaced apart from one another in the vertical direction due to the stacked configuration of the recoat assembly transverse actuator 2144 and the print head actuator 2154. In some embodiments, such as the embodiment of the actuator assembly 2102 depicted in
In the embodiments described herein, the recoat assembly transverse actuator 2144 and the print head actuator 2154 may be, for example and without limitation, mechanical actuators, electro-mechanical actuators, pneumatic actuators, hydraulic actuators, or any other actuator suitable for providing linear motion. Suitable actuators may include, without limitation, worm drive actuators, ball screw actuators, pneumatic pistons, hydraulic pistons, electro-mechanical linear actuators, or the like. In one particular embodiment, the recoat assembly transverse actuator 2144 and the print head actuator 2154 are linear actuators manufactured by Aerotech® Inc. of Pittsburgh, Pa., such as the PRO225LM Mechanical Bearing, Linear Motor Stage.
In embodiments, the recoat assembly transverse actuator 2144 and the print head actuator 2154 may each be a cohesive sub-system that is affixed to the rail 2180, such as when the recoat assembly transverse actuator 2144 and the print head actuator 2154 are PRO225LM Mechanical Bearing, Linear Motor Stages, for example. However, it should be understood that other embodiments are contemplated and possible, such as embodiments where the recoat assembly transverse actuator 2144 and the print head actuator 2154 comprise multiple components that are individually assembled onto the rail 2180 to form the recoat assembly transverse actuator 2144 and the print head actuator 2154, respectively.
Still referring to
Similarly, the print head 2150 is coupled to the print head actuator 2154 such that the print head 2150 is positioned below (i.e., in the −Z direction of the coordinate axes depicted in the figures) the first guide 2182 and the second guide 2184. When the actuator assembly 2102 is positioned over the cleaning station 2110, the build platform 2120, and the supply platform 2130 as depicted in
While
Referring to
The build material hopper 2360 may include an electrically actuated valve (not depicted) to release build material 2031 onto the build area 2124 as the build material hopper 2360 traverses over the build area 2124. In embodiments, the valve may be communicatively coupled to an electronic control unit 2300 (
Referring to
Referring to
In some embodiments, the recoat assembly 2200 includes a base member 2250, and the recoat assembly transverse actuator 2144 is coupled to the base member 2250, moving the base member 2250 in the lateral direction (i.e., in the X-direction as depicted). As referred to herein the base member 2250 may include any suitable structure of the recoat assembly 2200 coupled to the recoat assembly transverse actuator 2144, and may include a housing, a plate, or the like. In the embodiment depicted in
Recoat Assembly
Referring to
In some embodiments and referring to
For example and referring to
In embodiments, the recoat assembly 2200 includes a roller vertical actuator 2252 that is coupled to the first roller 2202 and/or the second roller 2204. The roller vertical actuator 2252 is operable to move the first roller 2202 and/or the second roller 2204 with respect to the base member 2250 in the vertical direction (i.e., in the Z-direction as depicted). In some embodiments, the vertical actuator 2252 is coupled to the front roller 2202 and the rear roller 2204 such that the front roller 2202 and the rear roller 2204 are movable with respect to the base member 2250 independently of one another. In some embodiments, the roller vertical actuator 2252 is a first roller vertical actuator 2252 coupled to the first roller 2202, and the recoat assembly 2200 further includes a second roller vertical actuator 2254 coupled to the second roller 2204, such that the front roller 2202 and the rear roller 2204 are movable with respect to the base member 2250 independently of one another. The first and second roller vertical actuators 2252, 2254 may include any suitable actuators, for example and without limitation, pneumatic actuators, motors, hydraulic actuators, or the like.
The recoat assembly 2200 further includes a first rotational actuator 2206 coupled to the first roller 2202, as best shown in
The first rotational actuator 2206 is configured to rotate the rotate the first roller 2202 about a first rotation axis 2226. Similarly, the second rotational actuator 2208 is configured to rotate the second roller 2204 about a second rotation axis 2228. In the embodiment depicted in
Recoat Sensors
In embodiments, the recoat assembly 2200 includes one or more sensors mechanically coupled to the roller supports 2210, 2212, 2216, and/or 2218, the one or more sensors configured to output a signal indicative of forces incident on the roller supports 2210, 2212, 2216, and/or 2218 via the first roller 2202 and/or the second roller 2204.
For example and referring to
In embodiments, the roller supports 2210, 2212, 2216, and/or 2218 define one or more flexures 2214 to which the strain gauges 2240A, 2240B are coupled. The strain gauges 2240A, 2240B are configured to detect elastic deformation of the flexures 2214, which may generally correlate to forces acting on the roller supports 2210, 2212, 2216, and/or 2218. In the depicted embodiment, the flexures 2214 are walls of a cavity extending through the roller supports 2210, 2212, 2216, and/or 2218, however, it should be understood that the flexures 2214 may include any suitable portion of the roller supports 2210, 2212, 2216, and/or 2218 that elastically deform such that strain of the flexures 2214 may be determined.
In embodiments, the strain gauges 2240A, 2240B are oriented in order to measure a strain. For example, in the embodiment depicted in
Referring to
In some embodiments, information related to a current layer of the object being built and/or a prior layer may be utilized to generate an expected force or pressure curve to be experienced as the recoat assembly 2200 traverses the build area 2124. In some embodiments, a geometry of the current layer of the object being built or a geometry of the immediately preceding layer that was built may be used to determine an expected pressure or force profile (e.g., shear forces expected to be experienced as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer, normal forces expected to be experienced as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer and/or any other type of expected force to be experienced as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer), output signals from the one or more sensors coupled to the roller supports (e.g., one or more strain gauges and/or one or more load cells) may be used to calculate a measured force or pressure as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer, a comparison between the expected pressure or measured force profile and the measured force or pressure may be made, and an action may be taken in response to the comparison. In some embodiments, a lookup table containing expected force or pressure information may be previously generated, such as based on calibration force measurements generated under various conditions (e.g., size of build area coated with binder, recoat traverse speed, recoat roller rotation speed, layer thickness, recoat roller geometry coating, and the like). For example, in some embodiments, when an expected pressure or force deviates from a measured pressure or force during spreading of material for a current layer by the recoat assembly 2200, the printing recoat process may be determined to be defective. The extent of force deviation may be used to determine a type of defect (e.g., a powder defect, a recoat roller defect, insufficient binder cure, a jetting defect, or the like). When a deviation beyond a given threshold is determined to have occurred, a corrective action may be taken, such as to adjust a recoat traverse speed for the current layer, adjust a roller rotation speed for the current layer, adjust a recoat traverse speed for one or more subsequent layers, adjust a roller rotation speed for one or more subsequent layers, adjust a height of one or more rollers for the current layer and/or for one or more subsequent layers, etc. Such measurements, comparisons, and control actions may be implemented by the electronic control unit 2300 executing one or more instructions stored in its memory component.
In some embodiments, the one or more sensors mechanically coupled to the roller supports 2210, 2212, 2216, and/or 2218 may include a load cell.
For example and referring to
Referring to
In some embodiments, an accelerometer 2244 is coupled to the first roller support 2210. While in the embodiment depicted in
In some embodiments, a roller support temperature sensor 2247 is coupled to the first roller support 2210. The roller support temperature sensor 2247 is operable to detect a temperature of the roller support 2210, which may be utilized to calibrate and/or compensate for a load cell reading from the load cell 2242. While in the embodiment depicted in
Recoat Energy Sources
Referring to
Recoat Hard Stops/Pivots
The hard stops 2410 may assist in limiting movement of the first roller 2202 and/or the second roller 2204 about the Y-axis as depicted, for example, as a result of actuation of the roller vertical actuator 2252. For example and referring particularly to
In embodiments, the hard stop 2410 includes a coupling portion 2414 that is coupled to the pivoting portion 2249 of the base member 2250, and a post portion 2412 that is movably engaged with the stationary portion 2251 of the base member 2250. For example, the post portion 2412 of the hard stop 2410 may be movable with respect to the stationary portion 2251 in a vertical direction (e.g., in the Z-direction as depicted). Movement of the post portion 2412 of the hard stop 2410 in the vertical direction (e.g., in the Z-direction as depicted) may be restricted. For example, a nut 2420 may be adjustably engaged with the post portion 2412, and may restrict movement of the post portion 2412 with respect to the stationary portion 2251 of the base member 2250. Because the coupling portion 2414 of the hard stop 2410 is coupled to the pivoting portion 2249 of the base member 2250, restriction of the movement of the post portion 2412 of the hard stop 2410 with respect to the stationary portion 2251 thereby restricts movement of the pivoting portion 2249 with respect to the stationary portion 2251 in the vertical direction (e.g., in the Z-direction as depicted). In some embodiments, the nut 2420 is adjustable on the post portion 2412 in the Z-direction as depicted. By moving the nut 2420 along the post portion 2412 in the Z-direction, the freedom of movement of the pivoting portion 2249 of the base member 2250, and accordingly the first roller 2202 and/or the second roller 2204, with respect to the stationary portion 2251 of the base member 2250 can be adjusted. Through the hard stop 2410, movement of the pivoting portion 2249 of the base member 2250, and accordingly the first roller 2202 and/or the second roller 2204, via actuation of the roller vertical actuator 2252 can be precisely tuned as desired. While in the embodiment depicted in
In some embodiments, the post portion 2412 of the hard stop 2410 extends through an aperture 2253 extending through the stationary portion 2251 of the base member 2250. In some embodiments, the recoat assembly 2200 includes a dust shield 2430 that at least partially encapsulates the aperture 2253 and/or at least a portion of the hard stop 2410. For example in the embodiment depicted in
Referring to
Referring to
In some embodiments, the recoat assembly 2200 includes one or more housing temperature sensors 2266. In the embodiment depicted in
In some embodiments, the recoat assembly 2200 includes one or more housing engagement members 2257 positioned at outboard ends of the recoat assembly 2200 and engaged with a housing of the additive manufacturing system 2100. The housing engagement members 2257 are generally configured to engage and “plow” or “scrape” build material 2031 off of the sides of the additive manufacturing system 2100. In embodiments, the housing engagement members 2257 may include any structure suitable, such as brushes, blades, or the like.
Referring to
In some embodiments, the recoat assembly 2200 includes a powder engaging member 2255 coupled to the base member 2250 (
Recoat Roller Positioning
In some embodiments, the recoat assembly 2200 includes multiple front rollers 2202 and/or multiple rear rollers 2204.
For example and referring to
Referring to
Referring to
Recoat Cleaning Member
Referring to
In some embodiments, the position of the cleaning member 2270 can be adjusted with respect to the first roller 2202 and/or the second roller 2204. For example and referring to
By rotating the first rotational member 2510 and/or the second rotational member 2520 with respect to one another, the position of the cleaning member 2270 with respect to the base member 2250, and accordingly the first roller 2202 and the second roller 2204, may be adjusted. For example, the position of the second rotational member 2520 with respect to the base member 2250 may be generally fixed. As the first rotational member 2510 and the second rotational member 2520 rotate with respect to one another, the eccentricity of the first eccentric tube 2514 and the second eccentric tube 2524 move the cleaning member 2270 with respect to the base member 2250, and accordingly with respect to the first roller 2202 and the second roller 2204. In this way, a user, such as a technician, can adjust the position of the cleaning member 2270 with respect to the first roller 2202 and the second roller 2204. In some embodiments, the cleaning position adjustment assembly 2500 further includes one or more pins 2540 that are insertable into the base member 2250 through notches of the first notched flange 2512 and the second notched flange 2522. The one or more pins 2540 restrict rotational movement of the first rotational member 2510 and the second rotational member 2520 with respect to one another, and with respect to the base member 2250. The one or more pins 2540 may be positioned into the base member 2250 through notches of the first notched flange 2512 and the second notched flange 2522, for example by a technician, once the cleaning member 2270 is positioned as desired. In some embodiments, the first rotational member 2510 and/or the second rotational member 2520 may be rotated with respect to one another and/or retained in position by an actuator or the like.
Referring to
Recoat Vacuum
Referring to
Without being bound by theory, airborne build material 2031 may include particles that are smaller than the build material 2031 that does not become airborne. Accordingly, by drawing airborne build material 2031 of smaller size out of the recoat assembly 2200, the mean particle size of the build material 2031 in the supply receptacle 2134 (
Referring to
Referring to
Referring to
Referring to
Recoat Controls
Referring to
In some embodiments, the electronic control unit 2300 includes a current sensor 2306. The current sensor 2306 generally senses a current driving the recoat assembly transverse actuator 2144, the first rotational actuator 2206, the second rotational actuator 2208, the vertical actuator 2160, and/or the print head actuator 2154. In embodiments in which the recoat assembly transverse actuator 2144, the first rotational actuator 2206, the second rotational actuator 2208, the vertical actuator 2160, and/or the print head actuator 2154 are electrically actuated, the current sensor 2306 senses current driving the recoat assembly transverse actuator 2144, the first rotational actuator 2206, the second rotational actuator 2208, the vertical actuator 2160, and/or the print head actuator 2154. While in the embodiment depicted in
In embodiments, the electronic control unit 2300 generally includes a processor 2302 and a memory component 2304. The memory component 2304 may be configured as volatile and/or nonvolatile memory, and as such may include random access memory (including SRAM, DRAM, and/or other types of RAM), flash memory, secure digital (SD) memory, registers, compact discs (CD), digital versatile discs (DVD), bernoulli cartridges, and/or other types of non-transitory computer-readable mediums. The processor 2302 may include any processing component operable to receive and execute instructions (such as from the memory component 2304). In embodiments, the electronic control unit 2300 may store one or more operating parameters for operating the additive manufacturing system 2100, as described in greater detail herein.
Operation of Recoat Assemblies
Methods for operating the recoat assembly 2200 will now be described with reference to the appended drawings.
Referring collectively to
As noted above, in embodiments, the electronic control unit 2300 may include one or more parameters for operating the additive manufacturing system 2100 (
In some embodiments, the at least one parameter is a height of the first roller 2202 (
In some embodiments, the at least one parameter of the additive manufacturing system 2100 comprises a speed at which the print head actuator 2154 moves the print head 2150 (
In some embodiments, the electronic control unit 2300 is configured to adjust the at least one operating parameter of the additive manufacturing system 2100 based on sensed current from the current sensor 2306. For example, in embodiments, the current sensor 2306 may detect current from the first rotational actuator 2206 and/or the second rotational actuator 2208. Detection of a current below a configurable threshold may be generally indicative of relatively low forces acting on the first roller 2202 and/or the second roller 2204. By contrast, detection of a current above a configurable threshold may be generally indicative of relatively high forces acting on the first roller 2202 and/or the second roller 2204. In some embodiments, the current sensor 2306 may sense a current driving the transverse actuator 2144 that moves the recoat assembly 2200 relative to the build area 2124. Similar to the first and second rotational actuators 2206, 2208, detection of a current below a configurable threshold may be generally indicative of relatively low forces acting on the first roller 2202 and/or the second roller 2204. By contrast, detection of a current above a configurable threshold may be generally indicative of relatively high forces acting on the first roller 2202 and/or the second roller 2204.
Referring to
At step 22604, the method comprises determining the first force on the first roller 2202 based on the first output signal of the first sensor. In some embodiments, a lookup table containing expected force or pressure information may be previously generated, such as based on calibration force measurements generated under various conditions (e.g., size of build area coated with binder, recoat traverse speed, recoat roller rotation speed, recoat roller direction, layer thickness, recoat roller geometry coating, and the like). In some embodiments, information related to a current layer of the object being built and/or a prior layer may be utilized to generate an expected force or pressure curve to be experienced as the recoat assembly 2200 traverses the build area 2124. In some embodiments, a geometry of the current layer of the object being built or a geometry of the immediately preceding layer that was built may be used to determine an expected pressure or force profile (e.g., shear forces expected to be experienced as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer, normal forces expected to be experienced as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer and/or any other type of expected force to be experienced as the recoat assembly 2200 traverses the build area 2124 to distribute material for the current layer), a comparison between the expected pressure or measured force profile and the measured force or pressure may be made, and an action may be taken in response to the comparison.
At step 22608, the method comprises adjusting the at least one operating parameter of the additive manufacturing system 2100 in response to the determined first force. For example, in some embodiments, the at least one operating parameter of the additive manufacturing system 2100 is adjusted based on a comparison of an expected force on the first roller 2202 to the first force on the first roller 2202 determined based on the first output signal of the first sensor. In embodiments, when a deviation beyond a given threshold is determined to have occurred, a corrective action may be taken, such as to adjust a recoat traverse speed for the current layer, adjust a roller rotation speed for the current layer, adjust a recoat traverse speed for one or more subsequent layers, adjust a roller rotation speed for one or more subsequent layers, adjust a height of one or more rollers for the current layer and/or for one or more subsequent layers, etc.
In some embodiments, when an expected pressure or force deviates from a measured pressure or force during spreading of material for a current layer by the recoat assembly 2200, the layer recoat process may be determined to be defective. The extent of force deviation may be used to determine a type of defect (e.g., a powder defect, a recoat roller defect, insufficient binder cure, a jetting defect, or the like.
In embodiments, each of steps 22602-22608 may be performed, for example, by the electronic control unit 2300. As noted above, in embodiments, the electronic control unit 2300 may include one or more parameters for operating the additive manufacturing system 2100. By adjusting at least one operating parameter in response to determined forces acting on the first roller 2202 (
In some embodiments, the at least one parameter is a speed of rotation of the first rotational actuator 2206. In embodiments, upon determining a force acting on the first roller 2202 below a configurable threshold, the electronic control unit 2300 may direct the first rotational actuator 2206 to decrease the speed at which the first rotational actuator 2206 rotates the first roller 2202. For example, the determination of comparatively low force or forces acting on the first roller 2202 may be indicative that the speed at which the first rotational actuator 2206 may be reduced while still being sufficient to fluidize the build material 2031. By contrast, upon detecting a force acting on the first roller 2202 exceeding a configurable threshold, the electronic control unit 2300 may direct may direct the first rotational actuator 2206 to increase the speed at which the first rotational actuator 2206 rotates the first roller 2202. For example, the determination of comparatively high force or forces acting on the first roller 2202 may be indicative that the speed at which the first rotational actuator 2206 is rotating the first roller 2202 is insufficient to fluidize the build material 2031 as desired.
In some embodiments, the at least one parameter is a target thickness of a subsequent layer of build material 2031 and/or the layer of build material 2031 being distributed. In embodiments, upon determining a force acting on the first roller 2202 below a configurable threshold, the electronic control unit 2300 may direct the recoat assembly 2200 to increase a target thickness of a subsequent layer of build material 2031, for example by changing the height of the recoat assembly 2200. For example, the determination of comparatively low force or forces acting on the first roller 2202 may be indicative that the thickness of the layer of build material 2031 distributed by the recoat assembly 2200 may be increased. By contrast, upon detecting a force acting on the first roller 2202 exceeding a configurable threshold, the electronic control unit 2300 may direct the recoat assembly 2200 to decrease a target thickness of a subsequent layer of build material 2031, for example by changing the height of the recoat assembly 2200. For example, the determination of comparatively high force or forces acting on the first roller 2202 may be indicative that the thickness of the layer of build material 2031 distributed by the recoat assembly 2200 should be decreased.
In some embodiments, the method illustrated in
In embodiments, the adjustment of the at least one operating parameter of the additive manufacturing system 2100 can be implemented at one or more times during a build cycle. For example, in embodiments, the at least one operating parameter may be adjusted while the layer of build material 2031 is being distributed by the recoat assembly 2200. In some embodiments, the at least one operating parameter of the additive manufacturing system 2100 is adjusted when a next layer of build material 2031 is distributed by the recoat assembly 2200.
In some embodiments, a wear parameter may be determined based on the determined first force. For example, as the first roller 2202 wears, for example through repeated contact with the build material 2031, the diameter of the first roller 2202 may generally decrease. The decreased diameter of the first roller 2202 may generally lead to lower forces on the first roller 2202 as the first roller 2202 distributes build material 2031.
In some embodiments, wear on other components of the recoat assembly 2200 may be determined based on the determined first force. For example, the first roller 2202 may be coupled to the base member 2250 (
In some embodiments, the method depicted in
In some embodiments, the method depicted in
In some embodiments, the method depicted in
Referring to
While the method described above includes moving the recoat assembly 2200 over a supply receptacle 2134, it should be understood that in some embodiments a supply receptacle 2134 is not provided, and instead build material 2031 may be placed on the build area 2124 through other devices, such as the build material hopper 2360 (
In embodiments, the electronic control unit 2300 may direct various components of the additive manufacturing system 2100 to perform steps 22702-22712. In embodiments, by irradiating the initial layer of build material 2031, the front energy source 2260 may act to cure binder material 2050 positioned on the build material 2031 of the build area 2124. By irradiating the second layer of build material 2031, the rear energy source 2262 may generally act to pre-heat the build material 2031, and/or further cure the binder material 2050.
By irradiating the build material 2031 with a front energy source 2260 that is separate from a rear energy source 2262, the intensity of energy emitted by the recoat assembly 2200 may be distributed, as compared to recoat assemblies including a single energy source, which may reduce defects in the binder material 2050 and/or the build material 2031. More particularly, the thermal power density of a single energy source heating system can quickly reach a limit due to space and cost constraints. Excessive power output in a single energy source heating system can be detrimental to the quality of the cure of the binder material 2050 in each layer of build material 2031, as large spikes in temperature may induce stress and cracks in the relatively weak parts and can cause uncontrolled evaporation of solvents within the binder material 2050. By including the front energy source 2260 and the rear energy source 2262, the thermal power intensity of the recoat assembly 2200 may be distributed. In particular and as noted above, including multiple energy sources (e.g., the front energy source 2260 and the rear energy source 2262), energy can be applied to build material 2031 (
Furthermore, because the recoat assembly 2200 includes the front energy source 2260 and the rear energy source 2262, operation of the recoat assembly 2200 may be maintained in the case of failure of the front energy source 2260 or the rear energy source 2262. In particular, by providing multiple energy sources (e.g., the front energy source 2260 and the rear energy source 2262), in the case of failure of one of the energy sources, the other energy source may continue to be utilized, so that the recoat assembly 2200 may continue to operate, thereby reducing downtime of the recoat assembly 2200.
The first roller 2204, in embodiments, is rotated at a rotational speed sufficient to fluidize at least a portion of the build material 2031. In some embodiments, the first roller 2204 is rotated at a rotational speed of at least 2.5 meters per second. In some embodiments, the first roller 2204 is rotated at a rotational speed of at least 2 meters per second. In some embodiments, the first roller 2204 is rotated at a rotational speed of at least 1 meter per second.
In some embodiments, the operation of the front energy source 2260 and/or the rear energy source 2262 may be controlled and modified. In embodiments, the front energy source 2260 and/or the rear energy source 2262 may be communicatively coupled to the electronic control unit 2300 through one or more relays, such as solid state relays, that facilitate control of the front energy source 2260 and/or the rear energy source 2262.
In some embodiments, the additive manufacturing system 2100 may include a temperature sensor 2286 communicatively coupled to the electronic control unit 2300. The temperature sensor 2286 may include any contact or non-contact sensor suitable for detecting a temperature of the build material 2031, for example and without limitation, one or more infrared thermometers, thermocouples, thermopiles or the like. As shown in
In some embodiments, the recoat assembly 2200 includes a distance sensor 2288 communicatively coupled to the electronic control unit 2300. The distance sensor 2288 is generally configured to detect a thickness of a layer of build material 2031 positioned below the recoat assembly 2200. In embodiments, the electronic control unit 2300 may receive a signal from the distance sensor 2288 indicative of the layer or build material 2031 moved to the build area 2124. The electronic control unit 2300 may change one or more parameters based on the detected thickness of the layer of build material 2031 such that the recoat assembly 2200 may move build material 2031 to the build area 2124 as desired. In embodiments, the distance sensor 2288 may include any sensor suitable for detecting a thickness of build material 2031, such as and without limitation, a laser sensor, an ultrasonic sensor, or the like.
In some embodiments, the second roller 2204 may be positioned above the first roller 2202 in the vertical direction (i.e., in the Z-direction as depicted). In these embodiments, only the first roller 2202 may contact the build material 2031, and the second roller 2204 may act as a spare roller that can be utilized in the case of failure or malfunction of the first roller 2202.
In some embodiments, the second roller 2204 is rotated in a rotation direction 2062 that is the opposite of the counter-rotation direction 2060 and the second roller 2204 contacts the build material 2031 within the build area 2124. The second roller 2204 may be rotated at a rotational velocity that corresponds to a linear velocity of the recoat assembly 2200. More particularly, by matching the rotational velocity of the second roller 2204 to match the linear velocity of the recoat assembly 2200, the second roller 2204 may generally act to compact the build material 2031, while causing minimal disruption to the build material 2031 as the recoat assembly 2200 moves with respect to the build area 2124. In embodiments, the rotational velocity of the first roller 2202 is greater than the rotational velocity of the second roller 2204. In some embodiments, as the second roller 2204 compacts the build material 2031, the second roller 2204 may be positioned lower than the first roller 2202 in the vertical direction (i.e., in the Z-direction as depicted).
In some embodiments, once the second layer of build material 2031 is deposited the first roller 2202 is moved upward in the vertical direction (i.e., in the Z-direction as depicted), such that the first roller 2202 is spaced apart from the second layer of build material 2031. The recoat assembly 2200 is then moved to the supply receptacle 2134 in a direction that is opposite of the coating direction 2040. In this way, the recoat assembly 2200 may be returned to the recoat home position 2148 (
In some embodiments, the first roller 2202 and/or the second roller 2204 may compact the build material 2031 in the build area 2124 as the recoat assembly 2200 moves back to the recoat home position 2148. For example and referring to
In some embodiments, before moving the recoat assembly 2200 to the supply receptacle 2134, the method further comprises moving the first roller 2202 and/or the second roller 2204 upward in the vertical direction (i.e., in the Z-direction as depicted). In some embodiments, the first roller 2202 and/or the second roller 2204 is moved upward between 8 micrometers and 12 micrometers in the vertical direction, inclusive of the endpoints. In some embodiments, the first roller 2202 and/or the second roller 2204 is moved upward about 10 micrometers in the vertical direction. In some embodiments, before moving the recoat assembly 2200 to the supply receptacle 2134, the method further comprises moving the first roller 2202 and/or the second roller 2204 upward in the vertical direction (i.e., in the Z-direction as depicted). In some embodiments, the first roller 2202 and/or the second roller 2204 is moved upward between 5 micrometers and 20 micrometers in the vertical direction, inclusive of the endpoints. By moving first roller 2202 and/or the second roller 2204 upward in the vertical direction, the first roller 2202 and/or the second roller 2204 may be positioned to compact the build material 2031 in the build area 2124.
In some embodiments, as the first roller 2202 and/or the second roller 2204 contacts the build material 2031 in the build area 2124 moving back toward the supply receptacle 2134, the first roller 2202 and/or the second roller 2204 is rotated at a rotational velocity that corresponds to the linear velocity of the recoat assembly 2200 moving back toward the supply receptacle 2134. As noted above, by correlating the rotational velocity of the first roller 2202 and/or the second roller 2204 to the linear velocity of the recoat assembly 2200, the first roller 2202 and/or the second roller 2204 may compact the build material 2031, with minimal disruption of the build material 2031 in the longitudinal direction (i.e., in the X-direction as depicted).
While
In some embodiments, the first roller 2202 and the second roller 2204 may be rotated in the counter-rotation direction 2060 as the recoat assembly 2200 moves in the coating direction 2040, as shown in
Referring to
In embodiments, each of steps 23002-23006 may be performed, for example, by the electronic control unit 2300.
In embodiments, the vacuum 2290 may draw the airborne build material 2031 out of the recoat assembly 2200 at one or more times during a build cycle. For example, in some embodiments, the step of drawing airborne build material 2031 out of the recoat assembly 2200 is subsequent or during to the step of moving the build material 2031. Put another way, the vacuum 2290 draws the build material 2031 out of the recoat assembly 2200 at the end of a build cycle. In some embodiments, the step of drawing airborne build material 2031 out of the recoat assembly 2200 is concurrent with the step of moving the build material 2031. Put another way, the airborne build material 2031 may be drawn out of the recoat assembly 2200 during the build cycle in a continuous or semi-continuous manner.
In some embodiments, the vacuum 2290 may apply a positive pressure to the recoat assembly 2200 to dislodge build material 2031 accumulated within the recoat assembly 2200. For example, in some embodiments, subsequent to moving the build material 2031, the vacuum 2290 directs a process gas, such as air or the like, to the recoat assembly 2200. In some embodiments, the vacuum 2290 may apply positive pressure while the recoat assembly 2200 is positioned over a drain that applies a negative pressure to collect the build material 2031. In embodiments, the drain may be positioned proximate to the build area 2124 (
Printing Assemblies
While
Referring to
As used herein, “build instructions” refer to the control commands for manipulating the operation of the apparatus 3100 to build a component 3080. The build instructions are defined by, for example, design deposition patterns for each layer of the component 3080 to be built and a plurality of motion controls defining commands setting forth an ordered operation of motors, actuators, printing assemblies, jet nozzles, and various other components of the apparatus to build the component 3080. The build instructions are defined based on a component design or model and mechanical specifications of the apparatus 3100. For example, an apparatus 3100 may include predefined and fixed distance between jet nozzles within a print head, referred to herein as “jet-spacing.” Embodiments described herein provide techniques for printing a component 3080 using sub jet-spacing indexing to deliver a high degree of distribution of binder that is otherwise not achievable unless the jet-spacing is reduced thus increasing the complexity and cost of a print head. In other words, for example, jet nozzles of a print head having a jet-spacing of 400 DPI (dots per inch) may achieve greater than 400 DPI deposition of binder through sub jet-spacing indexing as described herein.
The apparatus 3100 further receives build material 3040 and binder material 3050 that may be deposited layer-by-layer and drop-by-drop, respectively, according to the build instructions for building the component 3080. For example, the apparatus 3100 may form a layer of powder 3060 (also referred to herein as a layer of build material) in a build area 3120 (
As used herein, a “pixel” refers to a 2-dimensional spatial portion of the object or part to-be-printed by the apparatus 3100, and in particular, a current slice or layer of the three-dimensional part relative to its positioning along the build area. Each pixel corresponds to an image pixel defined in the design deposition pattern of the build instructions. The image pixel is the digital representation of a pixel. The image pixel includes a width defined by the jet-spacing of the jet nozzles of the apparatus 3100. As used herein, a “voxel” refers to a 3-dimensional spatial portion of the powder in the build area defined by the one or more drops of binder deposited within the pixel forming the current slice or layer of the three-dimensional part (e.g., the component 3080). It is understood that a voxel may not be cubic as the shape of the shape of the voxel depends on the wicking and curing behavior of the binder with the build material (e.g., the layer of powder that binder is deposited in).
Binder material 3050 may be deposited in various amounts at various locations within the layer of powder 3060 (e.g. build material) in the form of droplets. The locations and amounts of the droplets are defined in the “design deposition pattern,” which refers to a collection of image pixels forming the pattern of the desired slice of the build file, and when applied to by the apparatus 3100 to the layer of powder 3060 defines an “applied deposition pattern.” While the design deposition pattern defines the amount (e.g., the “drop volume”) and location (e.g., the location of the center of the droplet of binder on the layer of powder 3060), the applied deposition pattern refers to the distribution of the binder through the layer or layers of powder, which may include overlap into adjacent pixels or lower layers of powder. (See
Referring now to
In some embodiments, a second actuator assembly 3103 may be constructed to facilitate independent control of the printing assembly 3150 along a latitudinal axis (i.e., extending along the +/−Y-axis as depicted in the figures), which is generally perpendicular to the longitudinal axis (i.e., the working axis 3116). As described in more detail herein, the second actuator assembly 3103 may provide fine movement of the printing assembly 3150 along the longitudinal axis, herein referred to as indexing. The first actuator assembly 3102 and the second actuator assembly 3103 are generally referred to as printing head position control assembly. That is, the printing head position control assembly includes the first actuator assembly 3102 configured to move the printing head along the longitudinal axis and a second actuator assembly 3103 configured to move the printing head along a latitudinal axis. The printing head position control assembly may be controlled via signals generated by a control system 3010 such as an electronic control unit. The electronic control unit may include a processor and a non-transitory computer readable memory.
In some embodiments, the first actuator assembly 3102 includes a position sensor 3102a that provides the electronic control unit with position information of the recoat assembly 3140 and/or the printing assembly 3150 in a feedback control signal such that the electronic control unit may track the position of the recoat assembly 3140 and/or the printing assembly 3150 in response to the provided control signals. In some instances, the electronic control unit may make adjustments to the control signal provided to the first actuator assembly 3102 based on the position information provided by the position sensor. In embodiments, the position sensor may be an encoder, an ultrasonic sensor, a light-based sensor, a magnetic sensor, or the like embedded in or coupled to the first actuator assembly 3102.
As noted above, in the embodiments described herein the recoat assembly 3140 and the printing assembly 3150 are both located on the working axis 3116 of the apparatus 3100. As such, the movements of the recoat assembly 3140 and the printing assembly 3150 on the working axis 3116 occur along the same axis and are thus co-linear. With this configuration, the recoat assembly 3140 and the printing assembly 3150 may occupy the same space (or portions of the same space) along the working axis 3116 of the apparatus 3100 at different times during a single build cycle. In other embodiments, the components of the manufacturing apparatus 3100 traversing the working axis 3116, such as the recoat assembly 3140, the printing assembly 3150, or the like, need not be centered on the working axis 3116. In this instance, at least two of the components of the manufacturing apparatus 3100 are arranged with respect to the working axis 3116 such that, as the components traverse the working axis 3116, the components could occupy the same or an overlapping volume along the working axis 3116.
The recoat assembly 3140 is constructed to facilitate a distribution of a build material 3040 over the build area 3120 and the supply platform 3130. As will be described in greater detail herein, the printing assembly 3150 is constructed to facilitate a deposition of a binder material 3050 and/or other jettable composition materials (e.g., ink, fluid medium, nanoparticles, fluorescing particles, sintering aids, anti-sintering aids, things, etc.) over the build area 3120 as the printing assembly 3150 traverses the build area 3120 along a working axis 3116 of the apparatus 3100. In the embodiments of the apparatus 3100 described herein, the working axis 3116 of the apparatus 3100 is parallel to the +/−X axis of the coordinate axes depicted in the figures. In the embodiments described herein the cleaning station 3108, the build area 3120, the supply platform 3130, the recoat assembly 3140, and the printing assembly 3150 are positioned in series along the working axis 3116 of the apparatus 3100 between a home position 3151 of the printing assembly 3150, located proximate an end of the working axis 3116 in the −X direction, and a home position 3153 of the recoat assembly 3140, located proximate an end of the working axis 3116 in the +X direction. That is, the home position 3151 of the printing assembly 3150 and the home position 3153 of the recoat assembly 3140 are spaced apart from one another in a horizontal direction that is parallel to the +/−X axis of the coordinate axes depicted in the figures and at least the build area 3120 and the supply platform 3130 are positioned therebetween. In the embodiments, the build area 3120 is positioned between the cleaning station 3108 and the supply platform 3130 along the working axis 3116 of the apparatus 3100.
Still referring to
The build area 3120 is coupled to a build platform actuator 3122 to facilitate raising and lowering the build area 3120 relative to the working axis 3116 of the apparatus 3100 in a vertical direction (i.e., a direction parallel to the +/−Z directions of the coordinate axes depicted in the figures). The build platform actuator 3122 may be, for example and without limitation, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, or any other actuator suitable for imparting linear motion to the build area 3120 in a vertical direction. Suitable actuators may include, without limitation, a worm drive actuator, a ball screw actuator, a pneumatic piston, a hydraulic piston, an electro-mechanical linear actuator, or the like. The build area 3120 and build platform actuator 3122 are positioned in a build receptacle 3124 located below the working axis 3116 (i.e., in the −Z direction of the coordinate axes depicted in the figures) of the apparatus 3100. During operation of the apparatus 3100, the build area 3120 is retracted into the build receptacle 3124 by action of the build platform actuator 3122 after each layer of binder material 3050 is deposited on the build material 3040 located on the build area 3120.
Still referring to
The printing assembly 3150 comprises, among other features, a support bracket 3152, a printing head 3154, and a plurality of print heads 3156. The support bracket 3152 is movably coupled to the rail 3104 and the first actuator assembly 3102 of the apparatus 3100 while the printing head 3154 is positioned along an opposite end of the support bracket 3152 and movably coupled thereto via a second actuator assembly 3103 configured to operably index the printing head along a latitudinal axis. As described in greater detail herein, the printing head 3154 of the printing assembly 3150 may include two or more rows of a plurality of print heads 3156 and in some embodiments, at least one of which is movable relative to another row of a plurality of print heads 3156. This allows for at least the material deposit steps of the manufacturing process to be performed with enhanced jetting reliability and jetting resolution by varying a relative location of the at least one movable row of print heads 3156.
However, in some embodiments the printing assembly 3150 includes a plurality of print heads 3156, which may optionally comprise a plurality of jet nozzles 3158. The plurality of jet nozzles 3158 are spaced apart from one another in a direction transverse to a longitudinal axis, where a distance from a first jet nozzle to a second jet nozzle positioned adjacent the first jet of the plurality of jets defines a jet-spacing, as described in more detail herein.
Still referring to
In some embodiments, the control system 3010 may be further communicatively coupled to a computing device 3015, optionally via a network 3016, or directly via a communication link such as a wired or wireless connection. The computing device 3015 may include a display 3015a, a processing unit 3015b (e.g., having at least a processor and memory) and an input device 3015c, each of which may be communicatively coupled together and/or to the network 3016. The computing device 3015 may be configured to carry out processes such as generating executable instruction for building a component with the apparatus 3100. The process may implement CAD or other related three dimensional drafting and rendering systems as well as a slicing engine or the like. A slicing engine may be logic configured to receive a model or drawing of a component for building and process the model or drawing into build instructions defining a plurality of motion control operations, powder layer placements, deposition patterns for binder, and the like to be performed by the apparatus 3100 to build the component. The slicing engine may determine the number of layers of powder a build should include as well as locations within the layers of powder that binder should be dispensed. The deposition patterns of binder may also include defining the amount (volume) of binder that is to be dispensed at particular locations within the layer of powder.
In some embodiments, the network 3016 is a personal area network that utilizes Bluetooth technology to communicatively couple the control system 3010. In other embodiments, the network 3016 may include one or more computer networks (e.g., a personal area network, a local area network, or a wide area network), cellular networks, satellite networks, and/or a global positioning system and combinations thereof. Accordingly, the control system 3010 and/or the apparatus 3100 can be communicatively coupled to the network 3016 via wires, via a wide area network, via a local area network, via a personal area network, via a cellular network, via a satellite network, or the like. Suitable local area networks may include wired Ethernet and/or wireless technologies such as, for example, Wi-Fi. Suitable personal area networks may include wireless technologies such as, for example, IrDA, Bluetooth, Wireless USB, Z-Wave, ZigBee, and/or other near field communication protocols. Suitable personal area networks may similarly include wired computer buses such as, for example, USB and FireWire. Suitable cellular networks include, but are not limited to, technologies such as LTE, WiMAX, UMTS, CDMA, and GSM.
The apparatus 3100 further includes one or more fluid reservoirs fluidly coupled to the printing assembly 3150 via one or more conduit lines. In some embodiments, the printing assembly 3150 may also include one or more local fluid manifolds for locally storing fluid. In particular, the one or more fluid reservoirs may be fluidly coupled to the plurality of print heads 3156 disposed within the printing head 3154 of the printing assembly 3150. In this instance, a plurality of jet nozzles 3158 of each of the plurality of print heads 3156 (see
As will be described in greater detail herein, in some embodiments, the first fluid reservoir 3110 is coupled to a different subset (i.e., a first subset) of the plurality of print heads 3156 than the second fluid reservoir 3112 (i.e., a second subset) such that the plurality of print heads 3156 collectively receive and dispense each of the first material 3114 and the second material 3115, but each of the plurality of print heads 3156 of the printing assembly 3150 receive and dispense one of the first material 3114 or the second material 3115. In other embodiments, the first conduit line 3111 and the second conduit line 3113 may be coupled to one another at a coupling mechanism, such as, for example, a manifold, a valve, and/or the like. In this instance, the fluid reservoirs 3110, 3112 are in fluid communication with the coupling mechanism via the conduit lines 3111, 3113, where the coupling mechanism includes a third conduit line coupled thereto and extending to the printing head 3154. The coupling mechanism may be configured to selectively transition fluid communication between the fluid reservoirs 3110, 3112 and the printing head 3154 such that the plurality of print heads 3156 receive one of the first material 3114 or the second material 3115 in response to an actuation of the coupling mechanism. It should be understood that the coupling mechanism may be further configured to facilitate simultaneous fluid communication of the first fluid reservoir 3110 and the second fluid reservoir 3112 with the printing head 3154 such that the plurality of print heads 3156 receive both materials 3114, 3115 concurrently.
Referring to
The build material hopper 3170 may include an electrically actuated valve (not depicted) to release build material 3040 onto the build area 3120 as the build material hopper 3170 traverses over the build area 3120. In embodiments, the valve may be communicatively coupled to the control system 3010 (i.e. electronic control unit) which executes computer readable and executable instructions to open and close the valve based on the location of the build material hopper 3170 with respect to the build area 3120. The build material 3040 released onto the build area 3120 is then distributed over the build area 3120 with the recoat assembly 3140 as the recoat assembly 3140 traverses over the build area 3120.
Referring to
Referring now to
In some embodiments depicted herein, the printing head 3154 of the printing assembly 3150 includes multiple rows of print heads 3156, and in particular, at least a first print head row 3155 of print heads 3156 and a second print head row 3157 of print heads 3156. As will be described in greater detail herein, in other embodiments the printing head 3154 of the printing assembly 3150 may include additional or fewer rows of print heads 3156 (See,
It should further be understood that each of the plurality of print heads 3156 include a plurality of jet nozzles 3158. Despite the present example depicting each print head 3156 having four jet nozzles 3158 therein, it should be understood that this is merely for illustrative purposes and that each print head 3156 of the plurality of print heads 3156 in the first print head row 3155 and the second print head row 3157 include a plurality of jet nozzles 3158, which in many instances include many more than four jet nozzles. Accordingly, embodiments are contemplated and possible wherein each of the print heads 3156 of the plurality of print heads 3156 disposed within the printing head 3154 include greater or fewer jet nozzles 3158. By way of example only, each of the print heads 3156 may include a plurality of jet nozzles 3158 from about 5 nozzles to 50 nozzles, from about 50 nozzles to about 100 nozzles, from about 100 nozzles to about 500 nozzles, from about 500 nozzles to about 1000 nozzles, from about 1000 nozzles to about 2000 nozzles, from about 2000 nozzles to about 3000 nozzles, from about 3000 nozzles to about 4000 nozzles, from about 4000 nozzles to about 5000 nozzles, from about 5,000 nozzles to about 6,000 nozzles, with each jet nozzle 3158 spaced apart from another. The nozzles may be spaced apart from each other by 1/10 inch to about 1/1200 inch, or any value therebetween, for example 1/100 inch, 1/200 inch, 1/300 inch, 1/400 inch, 1/500 inch, 1/600 inch, 1/700 inch, 1/800 inch, 1/900 inch, 1/1000 inch, 1/1100 inch, or 1/1200 inch from one another. The distance “d” from a first jet to a second jet positioned adjacent the first jet of the plurality of jets corresponds to a jet-spacing (d) (
Referring in more detail to
Referring now to
As briefly described above, the plurality of print heads 3156 may be configured to slidably translate within the print head rows 3155, 3157, respectively, in a transverse direction relative to the working axis 3116 of the apparatus 3100 (i.e., in the +/−Y direction as shown in the figures). In the present example, the printing head 3154 of the printing assembly 3150 includes a pair of print head rows 3155, 3157 defined by three print heads 3156, respectively, in each row. It should be understood that the printing head 3154 of the printing assembly 3150 is configured to be modular such that in other embodiments additional print head rows and/or print heads 3156 may be included without departing from the scope of the present disclosure. Each of the print heads 3156 include a coupling feature 3149 attached thereto. Although not shown in
Referring specifically to
In a default position, the plurality of print heads 3156 of the first print head row 3155 may be positioned such that they at least partially overlap with the plurality of print heads 3156 of the second print head row 3157 in the +/−X direction of the coordinate axes (i.e. along the working axis 3116). It should be understood that in some embodiments the plurality of print heads 3156 of the first print head row 3155 are at least laterally offset (in the +/−Y direction of the coordinate axes of the figures) from the plurality of print heads 3156 of the second print head row 3157 by at least about one-half a width and/or diameter of a jet nozzle 3158 when the print head rows 3155, 3157 are in a default position. As will be described in greater detail herein, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 may be laterally offset relative to one another, in a direction transverse to the working axis 3116 (in the +/−Y direction of the coordinate axes depicted in the figures), such that the at least one print head 3156 of the first print head row 3155 and/or the second print head row 3157 is shifted in the +/−Y direction of the coordinate axes depicted in the figures relative to another print head 3156 of the adjacent row when the printing head 3154 is in an actuated position. However, it should be understood that in some embodiments at least one print head 3156 of the first print head row 3155 and/or the second print head row 3157 may continue to overlap with at least one opposing print head 3156 of the adjacent row when the printing head 3154 is in an actuated position (see
Still referring to
In the embodiments described herein, the actuator 3160 of the at least one print head 3156 may be, for example and without limitation, mechanical actuators, electro-mechanical actuators, pneumatic actuators, hydraulic actuators, motorized actuators, non-motorized actuators, or any other actuator suitable for providing at least a linear motion. Suitable actuators may include, without limitation, linear stages, worm drive actuators, ball screw actuators, pneumatic pistons, hydraulic pistons, electro-mechanical linear actuators, or the like. By way of example, the actuator 3160 may comprise a linear stage actuator such as a 150 MM linear motor stage with at least a 4 um accuracy.
Still referring to
In some embodiments, the printing head 3154 may include at least one spacer positioned between adjacent print heads 3156 of the first print head row 3155 such that a spacing between the adjacent and independently movable print heads 3156 increases and/or decreases uniformly relative to one another. In other embodiments, a limited number of the print heads 3156 within the first print head row 3155 may include one of the plurality of actuators 3160 coupled thereto (e.g., every other print head 3156 of the first print head row 3155; outer print heads 3156 of the first print head row; inner print heads 3156 of the first print head row; and the like) such that not every print head 3156 of the first print head row 3155 is independently movable.
In some embodiments, more than one of the plurality of print heads 3156 of the first print head row 3155 may be coupled to a single actuator 3160 such that the print heads 3156 coupled thereto may move in unison in the direction transverse to the working axis 3116 (the +/−Y direction in the coordinate axes shown in the figures). In some embodiments, all of the print heads 3156 in a single row may be coupled to a single actuator 3160 (e.g., all of the plurality of print heads 3156 in the first print head row 3155 may be coupled to a single actuator 3160 such that all print heads 3156 in the first print head row 3155 move in unison in the direction transverse to the working axis 3116 (the +/−Y direction in the coordinate axes shown in the figures). Alternatively, all of the print heads 3156 in multiple rows may be coupled to a single actuator 3160 (e.g., all of the plurality of print heads 3156 in the first print head row 3155 and the second print head row 3157 may be coupled to a single actuator 3160 such that all the print heads 3156 in the printing head 3154 move in unison in the direction transverse to the working axis 3116 (the +/−Y direction in the coordinate axes shown in the figures).
Still referring to
In other embodiments, the printing head 3154 may include at least one actuator 3160 coupled to the plurality of print heads 3156 defining the first print head row 3155 for moving the plurality of print heads 3156 and another actuator 3160 coupled to the plurality of print heads 3156 defining the first print head row 3155 for changing a distance (e.g., spacing) between the plurality of print heads 3156 of the first print head row 3155. In this instance, despite the plurality of print heads 3156 of the first print head row 3155 moving in unison with one another in response to an actuation of a single actuator 3160, a spacing between each of the plurality of print heads 3156 may be selectively controlled (e.g., increased or decreased) by another actuator 3160 coupled to the print heads 3156 of the first print head row 3155. In the present example, the plurality of print heads 3156 of the second print head row 3157 do not include an actuator coupled thereto such that the second print head row 3157 of the plurality of print heads 3156 are securely fixed relative to one another, relative to the support bracket 3152 (See
Referring now to
In other embodiments, the printing head 3154 of the printing assembly 3150 includes a plurality of actuators 3160, and in particular at least one actuator 3160 for each of the plurality of print heads 3156 of the second print head row 3157. In this instance, and as described in greater detail herein, each of the plurality of print heads 3156 of the second print head row 3157 may move relative to one another in response to an actuation of the respective actuator 3160 coupled thereto. In other words, each of the plurality of print heads 3156 of the second print head row 3157 are movable independent of one another such that adjacent print heads 3156 of the second print head row 3157 may translate in opposite directions and/or at varying degrees (i.e., distances) relative to one another along the +/−Y direction of the coordinate axes. With one or more of the print head 3156 in each of the print head rows 3155, 3157 coupled to at least one actuator 3160, the printing head 3154 of the printing assembly 3150 may generate a variable printing width that is configured to expand or contract as necessary.
Referring now to
In the present example, the plurality of print heads 3156 of the second print head row 3157 do not include an actuator coupled thereto such that the second print head row 3157 of the plurality of print heads 3156 is securely fixed relative to the plurality of print heads 3156 of the first print head row 3155. In other embodiments, the single actuator 3160 may be coupled to both the first print head row 3155 and the second print head row 3157 such that actuation of the actuator 3160 provides translation of both rows 3155, 3157 in unison relative to the support bracket 3152 (See
Referring to
In some embodiments, the actuator 3160 of the printing head 3154 is configured to move one or more of the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 in various other directions other than those shown and described above (i.e., directions other than in the +/−Y direction of the coordinate axes depicted in the figures). For example, the actuator 3160 of the printing head 3154 may be configured to move one or more of the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 in a direction parallel to the working axis 3116 of the apparatus 3100 (i.e., in the +/−X direction of the coordinate axes depicted in the figures), in another direction that is transverse to the working axis 3116 (i.e., in the +/−Z direction of the coordinate axes depicted in the figures), and the like.
Specifically referring to
In this instance, each of the plurality of print heads 3156 of the first print head row 3155 are movable independent of one another such that adjacent print heads 3156 of the first print head row 3155 may translate in opposite directions and/or at varying degrees (i.e., distances) relative to one another and the support bracket 3152 (see
Specifically referring to
Referring now to
Specifically referring to
Accordingly, each of the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 are movable independent of one another such that adjacent print heads 3156 of the first print head row 3155 and/or the second print head row 3157 may translate in opposite directions and/or at varying degrees (i.e., distances) relative to one another along the +/−Z direction of the coordinate axes. In other words, the plurality of actuators 3160 are configured to adjust a height between the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 relative to one another, the bottom end 3159 of the printing head 3154, and the build area 3120 over which the printing assembly 3150 is positioned over when depositing the binder material 3050, the first material 3114, the second material 3115, and the like. In other embodiments, a height of the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 may be adjusted in instances where the plurality of print heads 3156 are to be inactive during a current print cycle. In this instance, the first print head row 3155 or the second print head row 3157 is movable in the +Z direction of the coordinate axes to vertically offset the inactive plurality of print heads 3156 positioned therein.
Referring now to
Although not shown, it should further be understood that in other embodiments the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 may collectively be coupled to a single actuator 3160, respectively, rather than a plurality of actuators 3160 as shown and depicted herein. In this instance, the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 are simultaneously movable in unison relative adjacent print heads 3156 within the same print head row 3155, 3157. However, the plurality of print heads 3156 of the first print head row 3155 remains independently movable relative to the plurality of print heads 3156 of the second print head row 3157. In other embodiments, the plurality of print heads 3156 defining the first print head row 3155 and the second print head row 3157 may collectively be coupled to a single actuator 3160 such that both rows 3155, 3157 of print heads 3156 move in unison with one another relative to the support bracket 3152 (see
Specifically referring to
Referring now to
Accordingly, actuation of the third actuator 3160″ provides a simultaneous translation of the plurality of print heads 3156 defining the third print head row 3256 relative to the plurality of print heads 3156 defining the first print head row 3155 and the second print head row 3157. In this instance, a relative distance between each of the plurality of print heads 3156 of the third print head row 3256 is maintained such that the offset (i.e. spacing) between adjacent print heads 3156 defining the third print head row 3256 is not changed as the third print head row 3256 of print heads 3156 translates. In the present example, the plurality of print heads 3156 of the first print head row 3155 and the plurality of print heads 3156 of the third print head row 3256 are depicted as being moved in the −Y direction of the coordinate axes while the plurality of print heads 3156 of the second print head row 3157 disposed therebetween is depicted as being moved in the +Y direction of the coordinate axes.
It should be understood that the print heads 3156 of the rows may interchangeably trade positions and/or translate to various other lateral degrees than that shown and described herein. In some embodiments, the three rows of print heads 3156 may be collectively coupled to a single actuator 3160 such that the first print head row 3155, the second print head row 3157, and the third print head row 3256 of print heads 3156 are configured to move in unison relative to the support bracket 3152 (See
Referring now to
Further, the actuator (i.e., the second actuator 3160′) coupled to the at least one print head 3156 of the second print head row 3157 (i.e., the second print head 3156″) is configured to move the second print head 3156″ within the second print head row 3157 independent of the plurality of print heads 3156 of the second print head row 3157 and the plurality of print heads 3156 of the first print head row 3155 and the third print head row 3256. Similarly, the actuator (i.e., the third actuator 3160″) coupled to the at least one print head 3156 of the third print head row 3256 (i.e., the third print head 3156′″) is configured to move the third print head 3156′ within the third print head row 3256 independent of the plurality of print heads 3156 of the third print head row 3256 and the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157.
Still referring to
In the present example, the first print head 3156′ of the first print head row 3155 and the third print head 3156′″ of the third print head row 3256 are depicted as being moved in the −Y direction of the coordinate axes while the second print head 3156″ of the second print head row 3157 disposed therebetween is depicted as being moved in the +Y direction of the coordinate axes. In other embodiments, the first print head 3156′ of the first print head row 3155 and/or the second print head 3156″ of the second print head row 3157, and the other plurality of print heads 3156 within the print head rows 3155, 3157, respectively, may not include an actuator coupled thereto such that the first print head row 3155 and/or the second print head row 3157 of the plurality of print heads 3156 are securely fixed relative to at least the third print head 3156′″ of the third print head row 3256.
Still referring to
Referring now to
Specifically, actuation of the actuators 3160 provides a simultaneous translation of the plurality of print heads 3156 included in each of the first print head row 3155 and the third print head row 3256, respectively, relative to the fixed configuration of the plurality of print heads 3156 of the second print head row 3157. In this instance, a relative distance between each of the plurality of print heads 3156 of the first print head row 3155 and the third print head row 3256 are maintained such that the offset (i.e. spacing) between adjacent print heads 3156 within the respective rows are not changed as the print head rows 3155, 3256 of print heads 3156 translate. In the present example, the plurality of print heads 3156 of the first print head row 3155 are depicted as being moved in the −Y direction of the coordinate axes and the plurality of print heads 3156 of the third print head row 3256 are depicted as being moved in the +Y direction, while the plurality of print heads 3156 of the second print head row 3157 disposed therebetween is depicted as being fixed.
With the first print head row 3155 translated in the —Y direction and the third print head row 3256 translated in the +Y direction, and the second print head row 3157 maintained in a fixed orientation therebetween, an effective printing width of the printing head 3254 may be increased. In other words, with one or more of the print head rows 3155, 3157, 3256 coupled to at least one actuator 3160, the printing head 3154 of the printing assembly may generate a variable printing width that is configured to expand or contract the print head rows 3155, 3157, 3256 as necessary. It should be understood that a direction of translation and/or positions of the first print head row 3155 and the third print head row 3256 may be interchangeable and/or at varying other degrees than that shown and described herein.
Referring now to
In some embodiments, the actuators 3160 of the printing head 3254 are configured to move one or more of the plurality of print heads 3156 of the first print head row 3155, the second print head row 3157, and/or the third print head row 3256 in various other directions other than those shown and described above. For example, the actuators 3160 of the printing head 3254 may be configured to move one or more of the plurality of print heads 3156 of the first print head row 3155, the second print head row 3157, and/or the third print head row 3256 in a direction parallel to the working axis 3116 of the apparatus 3100 (i.e., in the +/−X direction of the coordinate axes depicted in the figures), in another direction transverse to the working axis 3116 (i.e., in the +/−Z direction of the coordinate axes depicted in the figures), and the like. It should be understood that other combinations of printing assemblies including one or more rows of movable and fixed print heads 3156 may be included in the printing head 3254 without departing from the scope of the present disclosure.
Referring now to
The fine actuator may comprise various devices, such as, for example, a piezoelectric linear positioner, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, linear stages, a belt-driven actuator, or any other actuator suitable for providing linear motion. The coarse actuator 3164 may comprise various devices, such as, for example, a magnetic linear drive, a mechanical actuator, an electro-mechanical actuator, a pneumatic actuator, a hydraulic actuator, linear stages, a belt-driven actuator, or any other actuator suitable for providing linear motion. It should be understood that although the present examples shown and described herein illustrate the fine actuator and the coarse actuator utilized with the printing assembly 3150, the actuators may similarly be incorporated other printing assemblies that include additional and/or fewer rows of print heads 3156 without departing from the scope of the present disclosure.
The following figures and description provide illustrative examples of printing assemblies including at least one of a fine actuator or coarse actuator and a corresponding movement degree of resolution of a plurality of print heads 3156 defining a print head row 3155 provided by the actuator.
Specifically referring to
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Referring now to
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In the present example, the plurality of print heads 3156 of the first print head row 3155 and the plurality of print heads 3156 of the second print head row 3157 deposit material along the build area 3120. Accordingly, each of the plurality of jet nozzles 3158 of the plurality of print heads 3156 from the first print head row 3155 and the second print head row 3157 may be mapped to trajectory across the build area 3120. The trajectory defines a plurality of pixels that may or may not receive binder deposited from one or more of the plurality of jet nozzles 3158 as the printing assembly 3150 traverses the build area 3120. It should be understood that a “pixel” refers to a 2-dimensional spatial portion of the object or part to-be-printed by the apparatus 3100, and in particular a current slice or layer of the three-dimensional part relative to its positioning along the build area 3120. Similarly, it is understood that a “voxel” refers to a 3-dimensional spatial portion of the build material that is combined with binder forming a physical portion of the component printed by the apparatus 3100. In some embodiments, a plurality of pixels and/or voxels defining spatial portions of the build material 3040 within the build area 3120 may be defined based on a digital build file (e.g., defining deposition patterns and/or apparatus control instructions stored and/or uploaded to the control system 3010) of the component to be built by the apparatus 3100. The pixels per layer of a build may be defined along to a trajectory the printing assembly 3150 is configured to traverse over the build area 3120. Accordingly, the control system 3010 may map one or more jet nozzles to a trajectory and the corresponding design deposition pattern for the current layer of the build such that the jet nozzles deposit prescribed drop volumes of binder at prescribed locations on the build material 3040 in the build area 3120. When the printing assembly 3150 and/or print heads 3156 are shifted, to achieve sub-pixel printing and/or jetting redundancy, the control system 3010 remaps trajectory-to-jet nozzle relationships so that the design deposition pattern defining the binder to be applied to the build material is associated with the new jet nozzles aligned with their new trajectories across the build area 3120 in response to indexing operations.
Still referring to
Alternatively, in response to determining that the printing assembly 3150 is positioned at the translated position 3253, the computer readable and executable instructions, when executed by the processor of the control system 3010 transmits a signal to the printing assembly 3150 to terminate release of material from the plurality of jet nozzles 3158 of the print heads 3156 of the first print head row 3155 and the second print head row 3157. Additionally and/or simultaneously, the control system 3010 transmits a signal to the first actuator assembly 3102 to terminate movement of the printing assembly 3150 along the working axis 3116 by ceasing actuation of the first actuator assembly 3102. With the printing assembly 3150 positioned at the translated position 3253, the plurality of pixels along the build area 3120 have received material thereon from at least the first print head row 3155 or the second print head row 3157 during the first pass of the printing assembly 3150 over the build area 3120 in the +X direction of the coordinate axes.
Referring now to
Alternatively, in response to determining that an additional layer of material (e.g., binder) is to be deposited from the printing assembly 3150 at step 3304, the computer readable and executable instructions, when executed by the processor of the control system 3010 transmits a signal to the actuator(s) 3160 of the printing assembly 3150 to actuate at least one of the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 relative to the support bracket 3152 of the printing assembly 3150 (See
Still referring to
In some embodiments, during a first pass a first pixel receives binder from a first jet nozzle 3158, while during a second pass the first pixel receives binder from a second jet nozzle 3158 as a result of a repositioning of one or more of the print heads 3156 between the passes. In some instances, the first pass may be configured to deposit a first amount of binder, which is a portion of a total amount prescribed for a portion of powder within a current layer to receive, and the second pass may be configured to deposit a second amount of binder that is the remainder amount of binder prescribed for a portion of powder within the current layer to receive. As described above, delivery of the first amount of binder may be accomplished by a first jet nozzle 3158, while the delivery of the second amount of binder may be accomplished by a second jet nozzle 3158.
It should be understood that lateral movement of the print heads 3156 of the first print head row 3155 and/or the second print head row 3157 relative to one another, and relative to a prior position of said print head rows 3155, 3157 from the default position, provides an enhanced jetting redundancy in the manufacturing process by increasing a reliability that a complete resolution of each of the plurality of pixels on the build area 3120 receives an adequate deposition of material thereon.
It should be understood that in some embodiments movement of the print head rows 3155, 3157 of print heads 3156 at step 3308 may be at an arbitrary fraction, where the control system 3010 transmit a signal to the actuators 3160 to move the first print head row 3155 and/or the second print head row 3157 of print heads 3156 to a randomly generated position relative to one another. In this embodiment, a jetting redundancy by the printing assembly 3150 is passively provided through the repositioning of the plurality of print heads 3156 of each print head row 3155, 3157 in an uncalculated manner such that the plurality of pixels along the build area 3120 are effectively aligned with a randomly aligned jet nozzle 3158 during a second pass of the printing assembly 3150.
In other embodiments, movement of the print head rows 3155, 3157 relative to one another, and relative to a prior position of said print head rows 3155, 3157 during a first pass of the printing assembly 3150, may be predetermined to predefined locations by the control system 3010. In this instance, the compute readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the actuators 3160 to move the first print head row 3155 and/or the second print head row 3157 of print heads 3156 to a measured position that varies relative to a prior position of the print head rows 3155, 3157 during the first pass. In this embodiment, a jetting redundancy by the printing assembly 3150 is actively provided through the repositioning of the plurality of print heads 3156 of each print head row 3155, 3157 in a calculated manner such that the plurality of pixels along the build area 3120 are specifically aligned with a jet nozzles 3158 during a second pass of the printing assembly 3150 that is intentionally varied from the first pass. For example, the control system 3010 may transmit a signal to the actuators 3160 coupled to the print head rows 3155, 3157, respectively, to translate the print heads 3156 of the print head rows 3155, 3157 in a manner such that the print head rows 3155, 3157 trade positions relative to one another.
The control system 3010 may determine the calculated positions of the plurality of print heads 3156 of the print head rows 3155, 3157 through various systems, such as, for example, a camera image, a sensor output, a calibration pattern, and the like. In either instance, movement of the print head rows 3155, 3157 of print heads 3156 for a second pass (i.e., either a return pass over a current layer of powder or a pass over a new layer of powder applied on top of the previous layer) of the printing assembly 3150 provides an enhanced, material jetting redundancy of the manufacturing process by increasing a reliability that a complete resolution of each of the plurality of pixels on the build area 3120 receives an adequate deposition of material thereon from more than one jet nozzle 3158. It should be understood that in other embodiments movement of the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 may occur prior to a first pass of the printing assembly 3150 over the build area 3120 at step 3302.
Turning now to
In one instance, an apparatus may be equipped with print heads 3156 configured to deliver a drop of binder material in 400 DPI (dots per inch) intervals along a latitudinal axis. However, by enabling the printing assembly 3150 with a second actuator assembly 3103, the printing assembly may be configured to deliver drops of binder material in much finer increments over subsequent passes along the longitudinal axis by implementing sub-pixel index distances of the printing assembly 3150. For example, a 400 DPI print head may be configured to dispense drops of binder between two passes along the longitudinal axis by implementing a sub jet-spacing index of the printing assembly 3150 of about one-half a jet-spacing achieving the equivalence of an 800 DPI print head.
In other words, the space between adjacent jet nozzles 3158 is fixed therefore there is a fixed spacing between placement of binder across a layer of powder in a single pass. However, by implementing a mechanical shift (e.g., referred to herein as an “index” along the latitudinal axis) of the printing assembly 3150, a corresponding index of the jet nozzles 3158 is achieved and a second deposition of binder on the same layer or a subsequent layer of powder may be performed thereby increasing the resolution in which binder may be deposited. Correspondingly, build instructions generated for building the component may define pixels having sub-pixels with a higher resolution than the mechanical resolution defined by the jet-spacing (d). Jet-spacing (d) is the center-to-center lateral distance between adjacent jets in the same row of the same print head.
To achieve printing of a higher resolution design deposition pattern (e.g., 3125
In further embodiments, the implementation of a second actuator assembly 3103 configured to index the printing assembly 3150 along a latitudinal axis enables methods of random redundancy within a build to reduce or remove a compounding effect of a malfunctioning jet. Such embodiments, will be described in more detail with reference to
Suitable actuators may include, without limitation, linear stages, worm drive actuators, ball screw actuators, pneumatic pistons, hydraulic pistons, electro-mechanical linear actuators, or the like. By way of example, the second actuator assembly 3103 may comprise a linear stage actuator such as a 150 MM linear motor stage with at least a 4 um accuracy. In some instances, the first actuator assembly 3102 and/or the second actuator assembly 3103 may include a position sensor 3102a and/or 3103a, respectively, that provides the electronic control unit with position information in a feedback control signal such that the electronic control unit may track the position of the printing assembly 3150 in response to the provided control signals. In some instances, the electronic control unit may make adjustments to the control signal provided to the first actuator assembly 3102 and/or the second actuator assembly 3103 based on the position information provided by the position sensor 3102a and/or 3103a. In embodiments, the position sensor 3102a and/or 3103a may be an encoder, an ultrasonic sensor, a light-based sensor, a magnetic sensor, or the like embedded in or coupled to the first actuator assembly 3102 and/or the second actuator assembly 3103.
Turning now to
As referenced above the space from one jet nozzle 3158 to an adjacent jet nozzle 3158 defines a jet-spacing (d) which correlates to the an image pixel. To increase the resolution of a deposition pattern (e.g., 3125, 3126, or 3127,
For example, for a first pass along the working axis (i.e., longitudinal axis) the printing assembly 3150 may be indexed at a position I0 and a second pass, for example, in the opposite direction to the first pass may be indexed to a position I1 as depicted in
The center location of a pixel 3180 and an adjacent pixel corresponds to the jet-spacing (d) of one jet nozzle 3158 to an adjacent jet nozzle 3158. Whereas the center of a sub-pixel 3181A-3181F may be defined within the build instructions as an incremental amount of the jet-spacing (d), thus optionally defining one or more sub-pixel centers 3181A-3181F within a pixel 3180. The sub-pixels 3181A-3181F may further be assigned a drop volume of binder for deposition by a jet nozzle 3158 during a build operation. The size (or foot print) of the sub-pixel may depend on the drop volume of a droplet of binder to be deposited on the corresponding portion of the layer of powder (e.g., build material 3040) that the center of the sub-pixel 3181A-3181F maps to according to the design deposition pattern 3125. In some embodiments, the size sub-pixel may be based on the speed the printing assembly 3150 traverses the build area 3120, the nature or type of the build material 3040 (
Still referring to
Turning to
While a predefined amount of binder for a pixel may be deposited at once within a pixel during a single pass, by dividing the predefined amount of binder for a pixel up into one or more sub-pixel regions during one or more passes of the printing assembly 3150 with indexing of the printing assembly 3150 between passes binder may be more uniformly integrated with neighboring voxels of build material (e.g., powder) in the build area 3120.
Referring to
Turning to
More specifically, this is accomplished by the fine and coarse motion control of the printing assembly provided by the printing head position control assembly comprising a first actuator assembly 3102 configured to move the printing head along the longitudinal axis and a second actuator assembly 3103 configured to move the printing head along a latitudinal axis.
In further embodiments of the apparatus, the printing assembly 3150 may be indexed between passes over a single layer of powder or between layers of powder to randomize the location of a jet nozzle 3158 or print head 3156 that may be malfunctioning. The indexing may be accomplished by moving the printing assembly 3150 along the latitudinal axis with the second actuator assembly 3103. The indexing motion of the printing assembly 3150 may be predetermined by the slicing engine when determining the deposition pattern for building the component or on-the-fly by the electronic control unit of the apparatus when, for example, a malfunctioning jet nozzle 3158 or print head 3156 is detected. An advantage of predefining the random indexing of the printing assembly 3150 with the slicing engine is that the association of a jet nozzle 3158 with various a trajectories along the longitudinal axis may be known through a build process of a component. For example, a history of jet nozzle 3158 and trajectory alignment for each pass during a build process may be generated and used for post-production analysis of a component should one or more jet nozzles or print heads is determined to have malfunctioned during the build.
As used herein, the term “predefined random index” or “predefined random indexing” refers to the randomized indexing values defined by the slicing engine when developing the executable instructions for the apparatus to execute during a build. Furthermore, the term “predefined” refers to the prior planning of indexing the printing assembly 3150 by the slicing engine and the term “random” refers to the aspect that the amount a printing assembly 3150 is indexed, in one instance, may be different from the amount the printing assembly 3150 is indexed in a second instance and may not be bound to any functional relationship except, for example, a build size of a component. That is, if a build size of a component has a build width of 3100 units and the printing assembly 3150 has jet nozzles 3158 positioned along a latitudinal axis to cover a build width up to 150 units, the randomly chosen index value may be 1 to 50 units so that the entire build width which requires deposition of binder during a pass of the printing assembly over the build area may be associated with a jet nozzle 3158. The term “units” used herein may refer to any know unit of measure used by the apparatus, for example inches, meters, millimeters, etc. Additionally, the unit values used herein are merely for explanatory purposes and not intended to limit the disclosure.
Moreover, the randomness of the indexing values may be determined by the slicing engine so that a jet nozzle corresponding to a first trajectory along a longitudinal axis during a first pass may be randomly assigned to a second trajectory along a longitudinal axis during a second pass (e.g., a consecutive pass with respect to the first pass). It is understood that indexing of the printing assembly 3150 may not be executed between every pass of the printing assembly 3150 over the build area 3120. However, in some instances the slicing engine may be configured, for example, by an engineer or operator when developing the executable instructions, to include an indexing command or step between each consecutive pass of the printing assembly 3150 over the build area or at less frequent intervals, such as every other pass, every second pass or any randomly chosen number of passes between 1 and the total number of passes defined to build a component.
In some instances, the electronic control unit of the apparatus 3100 may be configured to execute indexing of the printing assembly 3150 independently from the predefined random indexes determined by the slicing engine. That is, the electronic control unit of the apparatus 3100 may “on-the-fly,” between passes, implement an indexing operation of the printing assembly 3150. Such an operation may be triggered by a sensor or other indication that a print head or a jet nozzle is malfunctioning. In some instances, however, the electronic control unit may implement a random amount of indexing of the printing assembly 3150 after a predetermined number of passes over the build area 3120.
Referring to
After at least one pass over the build area 3120, the control system may execute an instruction in the build instructions to index the printing assembly 3150 a predefined random index causing the jet nozzles 3158 of the printing assembly 3150 to move a lateral distance along the latitudinal axis in a first direction. Now that the jet nozzles 3158 align with new trajectories over the build area 3120 the control system 3010 remaps the build instructions for pixels defined in the deposition pattern to the jet nozzles configured to traverse the build area 3120 based on their new trajectory after indexing such that a jet nozzle 3158 is configured to deposit binder according to the build instructions associated with their current latitudinal position along the latitudinal axis. Remapping of the deposition pattern include digitally shifting the deposition pattern in a second direction opposite the first direction which the jet nozzles were indexed so that jet nozzles may be assigned the build instructions for the portion of the component that corresponds to their new trajectory after being indexed. In other words, in response to a mechanical shift in a first direction a digital shift in a second direction, opposite the first direction, but in the same absolute amount is needed to continue to build the component on the build area 3120.
Turning to
In operation, the control system 3010 maps build instructions for pixels defined in the deposition pattern to the jet nozzles 3158 configured to traverse the build area 3120 based on their planned trajectory such that a jet nozzle 3158 is configured to deposit binder according to the build instructions associated with their current latitudinal position along the latitudinal axis. Furthermore, the control system 3010 of the apparatus 3100 may cause select ones of the plurality of jet nozzles to dispense one or more drops of binder on a powder layer based on a deposition pattern defined by a slicing engine as the printing head traverses along the longitudinal axis applying binder, where the first jet of the plurality of jets corresponds to a first trajectory assigned by the slicing engine.
The control system 3010 of the apparatus 3100 may then index the printing head by an integer number of pixels along the latitudinal axis such that the first jet corresponds to a second trajectory and another jet corresponds to the first trajectory assigned by the slicing engine and subsequently cause the indexed printing head to traverse along the longitudinal axis and apply binder to the powder layer in the deposition pattern defined by the slicing engine. The control system 3010, in response to the indexing, remaps build instructions for pixels defined in the deposition pattern to the jet nozzles 3158 configured to traverse the build area 3120 based on their new trajectory such that a jet nozzle is configured to deposit binder according to the build instructions associated with their current latitudinal position along the latitudinal axis after indexing.
In some embodiments, an image processing device 3014 (
The prior embodiments describe and depict systems and methods for controlling binder or other material application to a build area by implement additional control of the printing assembly 3150 through a second actuator assembly 3103 that controls positioning of printing assembly 3150 along the latitudinal axis. A further consideration when applying binder is the bleed effect. That is, binder jet printing involves layerwise deposition of drops of liquid binder into powder. Drops of binder penetrate the powder and undergo a phase change (curing) to bind the powder particles together layer by layer. However, as it becomes desirable to increase the speed at which layers are built, deposited binder may not have sufficient energy and/or time to undergo a phase change before additional binder is added in subsequent print layers. That is, binder cure time may be rate limiting. This results in downward flow of binder beyond that layer in which the binder is deposited. Printed geometry with regions having downward-facing surfaces are at risk of having areas that become excessively wet resulting in surface defects and weak green strengths.
The following provides a solution to this issue of binder bleed by controlling the amount of binder that is deposited in layers having one or more layers applied above (along the Z-axis). Turning now to
A slicing engine or similar tool configured to generate executable instructions defining print head movements, design deposition patterns, and amounts for binder or other materials may define a layer to layer amount of binder to apply to vertically adjacent portions 3220 of powder estimating a voxel when binder is received. The amount of binder to apply to vertically adjacent portions 3220 of powder may be defined by the total number of adjacent layers over an attenuation length. For example, a first portion of powder in a stack of multiple layers (e.g., 2 or more, 3 or more, 4 or more, 5 or more) may be receive a first amount of binder that is less that the amount of binder deposited in a second portion of powder positioned above the first voxel. The amount of binder deposited in successive vertically aligned voxels of powder in subsequent layers of powder progressively increases to a predetermined volume. In some embodiments, the amount of binder dispensed in successive vertically aligned portions 3220 of powder in subsequent layers of powder progressively increases over an attenuation length defined by a predetermined number of layers of powder. Similarly, the amount of binder dispensed in successive vertically aligned portions 3220 of powder in subsequent layers of powder may progressively increase over an attenuation length defined by a predetermined number of layers of powder when the predetermined number of layers is greater than a predetermined thickness threshold. That is, the slicing engine may be configured to only apply bleed control for layers having greater than a predetermined thickness threshold (i.e., greater than a predetermined number of layers).
The amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers may be based upon one or more properties. These may include, but are not limited to, a property of the powder material such as a packing density of a powder material, an amount of time a binder wicks before setting or curing, the type of binder or type of powder, an exposure time of a curing energy source (e.g., an infrared, ultraviolet or other energy source) and/or other properties.
In operation, controlling binder bleed as disclosed herein, enables an apparatus to apply more layers of a build more efficiently and at a faster pace without being limited by a binder's curing rate.
Referring back to
In other embodiments, the control system 3010 transmits a signal to the first actuator assembly 3102 of the apparatus 3100 to translate the printing assembly 3150 from the translated position 3253 to the home position 3151 prior to initiating the second pass, such that the printing head 3154 again moves over the build area 3120 from the home position 3151 to the translated position 3253 during the second pass. In this instance, the printing head 3154 moves over the build area 3120 from the home position 3151 to the translated position 3253 as additional material is released from the printing head 3154 during the second pass. The control system 3010 repeats the steps described in detail above until the three-dimensional part to be printed by the apparatus 3100 is complete and no additional material is to be deposited at step 3306.
Although the present example of the exemplary method 3300 depicts and describes the printing assembly 3150 of the apparatus 3100 being initially positioned at the home position 3151 prior to moving to the translated position 3253, and the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 being arranged in the default position (
Referring now to
Referring to
In the present example, the plurality of print heads 3156 of the first print head row 3155 and the plurality of print heads 3156 of the second print head row 3157 deposit material along the build area 3120. Accordingly, at least some of the plurality of jet nozzles 3158 of the plurality of print heads 3156 from the first print head row 3155 and the second print head row 3157 jet material on at least one pixel positioned along the build area 3120. In this instance, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are in a default position relative to one another as the printing assembly 3150 deposits material onto the build area 3120 of the apparatus 3100. As will be described in greater detail herein, in other embodiments the plurality of print heads 3156 of the first print head row 3155 may deposit a different material than the plurality of print heads 3156 of the second print head row 3157 (see
Still referring to
Alternatively, in response to determining that the printing assembly 3150 is positioned at the translated position 3253, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the printing head 3154 to terminate release of the material from the plurality of jet nozzles 3158 of the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157. Additionally and/or simultaneously, the control system 3010 transmits a signal to the first actuator assembly 3102 to terminate movement of the printing assembly 3150 along the working axis 3116 by ceasing actuation of the first actuator assembly 3102. With the printing assembly 3150 positioned at the translated position 3253, the plurality of pixels positioned along the build area 3120 have received material thereon from at least the first print head row 3155 or the second print head row 3157 during the first pass of the printing assembly 3150 over the build area 3120 in the +X direction of the coordinate axes.
Referring now to
Alternatively, in response to determining that an additional layer of material (e.g., binder) is to be deposited from the printing assembly 3150 at step 3404, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the image processing device 3014 of the apparatus 3100 (see
Referring to
Accordingly, the computer readable and executable instructions, when executed by the processor of the control system 3010, perform a mapping of the plurality of pixels to identify a necessary development of the part at each of the plurality of pixels. By mapping the plurality of pixels and determining the progressive development of the part at each pixel thus far, the control system 3010 of the apparatus 3100 may adjust a position and/or arrangement of the plurality of print heads 3156 of the printing assembly 3150 for the subsequent pass (e.g., a second pass) to increase a likelihood that the plurality of pixels receive an adequate quantity of material disposed thereon from one or more different jet nozzles 3158 of the plurality of jet nozzles 3158.
Referring back to
In this instance, the plurality of jet nozzles 3158 of each of the plurality of print heads 3156 included in the first print head row 3155 and the second print head row 3157 is repositioned from a default position to an actuated position that differs from the default position by at least some incremental distance (e.g., incremental distances “A”-“G” of
Referring back to
In other embodiments, the control system 3010 transmits a signal to the first actuator assembly 3102 of the apparatus 3100 to translate the printing assembly 3150 from the translated position 3253 to the home position 3151 prior to initiating the second pass, such that the printing head 3154 again moves over the build area 3120 from the home position 3151 to the translated position 3253 during the second pass. In this instance, the printing head 3154 moves over the build area 3120 from the home position 3151 to the translated position 3253 as additional material is released from the printing head 3154 during the second pass.
As described in greater detail above, in some embodiments the control system 3010 may actuate the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 relative to one another and the support bracket 3152 during a first pass and/or a second pass in various manners. For example, such movement of the print heads 3156 may be randomly generated by the control system 3010 or predetermined based on calculated measurements of the previous positions of the plurality of print heads 3156 during the prior pass of the printing assembly 3150. In either instance, movement of the print head rows 3155, 3157 of print heads 3156 prior to each pass of the printing assembly 3150 provides an enhanced, material jetting redundancy of the manufacturing process by increasing a reliability that a complete resolution of each of the plurality of pixels on the build area 3120 receives an adequate deposition of material thereon from more than one jet nozzle 3158. The control system 3010 proceeds to repeats the steps described in detail above until the three-dimensional part to be printed by the apparatus 3100 is complete and no additional material is to be deposited at step 3406.
Although the present example of the exemplary method 3400 depicts and describes the printing assembly 3150 of the apparatus 3100 being initially positioned at the home position 3151 prior to moving to the translated position 3253, and the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 being arranged in the default position (
Referring now to
Referring to
In the present example, the plurality of print heads 3156 of the first print head row 3155 and the plurality of print heads 3156 of the second print head row 3157 deposit material along the build area 3120. Accordingly, at least some of the plurality of jet nozzles 3158 of the plurality of print heads 3156 from the first print head row 3155 and the second print head row 3157 jet material on at least one pixel positioned along the build area 3120. In this instance, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are in a default position relative to one another as the printing assembly 3150 deposits material onto the build area 3120 of the apparatus 3100. As will be described in greater detail herein, in other embodiments the plurality of print heads 3156 of the first print head row 3155 may deposit a different material than the plurality of print heads 3156 of the second print head row 3157 (see
Still referring to
The compute readable and executable instructions executed by the processor causes the control system 3010 to determine whether the printing assembly 3150 has reached the translated position 3253 located in the +/−X direction at or past an edge of the build area 3120 where material is to be deposited by the printing assembly 3150 in the first pass. The control system 3010 determines whether the printing assembly 3150 has reached the translated position 3253 by, for example, monitoring a relative position of the printing assembly 3150 along the rail 3104 as the printing assembly 3150 translates along the working axis 3116 of the apparatus 3100 (i.e., +X direction of the coordinate axes of the figures) to the translated position 3253.
Referring to
Alternatively, in response to determining that the printing assembly 3150 is positioned at the translated position 3253, the control system 3010 transmits a signal to the printing head 3154 to terminate release of material from the plurality of jet nozzles 3158 of the plurality of print heads 3156. Additionally and/or simultaneously, the instructions executed by the processor causes the control system 3010 to transmit a signal to the first actuator assembly 3102 to terminate movement of the printing assembly 3150 along the working axis 3116 by ceasing actuation of the first actuator assembly 3102. With the printing assembly 3150 positioned at the translated position 3253, the plurality of pixels positioned along the build area 3120 have received material thereon from at least the first print head row 3155 or the second print head row 3157 during the first pass of the printing assembly 3150 over the build area 3120 in the +X direction of the coordinate axes.
Still referring to
This determination by the control system 3010 may be performed via various devices and/or systems capable of detecting, monitoring, and/or measuring an output of the material from the plurality of jet nozzles 3158. In the present example, the printing assembly 3150 includes at least one sensor (e.g., a camera) for each of the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157, such that the plurality of sensors are configured to monitor a material output from each of the plurality of jet nozzles 3158. In response to the control system 3010 determining that the output of material from the plurality of jet nozzles 3158 of each of the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are equal to the predetermined threshold, the computer readable and executable instructions executed by the processor causes the control system 3010 to determine whether an additional layer of material (e.g., binder) is to be deposited from the printing assembly 3150 at step 3508.
Still referring to
Referring now to
As discussed in detail above, such defects and/or errors may be caused by a misfire and/or clog of one or more of the plurality of jet nozzles 3158 of the plurality of print heads 3156. In this instance, moving the first print head row 3155 and/or the second print head row 3157 of the plurality of print heads 3156 relative to one another and relative to the support bracket 3152 realigns the plurality of jet nozzles 3158 with the plurality of pixels. In this instance, the plurality of print heads 3156 are actuated only in response to the control system 3010 determining the occurrence of a possible error such that the plurality of print heads 3156 of the print head rows 3155, 3157 otherwise remain in a fixed arrangement relative to one another. Accordingly, each of the pixels along the build area 3120 may receive material from at least a different jet nozzle 3158 during a second pass than from the jet nozzle 3158 that was aligned with said pixel during a first pass of the printing assembly 3150.
Still referring to
Although the present example of the exemplary method 3500 depicts and describes the printing assembly 3150 of the apparatus 3100 being initially positioned at the home position 3151 prior to moving to the translated position 3253, and the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 being arranged in the default position (
Referring now to
Referring to
At step 3604, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the plurality of print heads 3156 of the first print head row 3155 to release the first material 3114 from the first fluid reservoir 3110 through the plurality of jet nozzles 3158 of the print heads 3156 defining the first print head row 3155. The first material 3114 is transferred to the print heads 3156 and deposited onto the build area 3120 through the plurality of jet nozzles 3158 as the printing assembly 3150 moves across the build area 3120. At step 3606, the control system 3010 transmits a signal to the plurality of print heads 3156 of the second print head row 3157 to release the second material 3115 from the second fluid reservoir 3112 through the plurality of jet nozzles 3158 of the print heads 3156 defining the second print head row 3157. The second material 3115 is transferred to the print heads 3156 and deposited onto the build area 3120 through the plurality of jet nozzles 3158 as the printing assembly 3150 moves across the build area 3120.
Accordingly, each of the plurality of jet nozzles 3158 of the plurality of print heads 3156 from the first print head row 3155 and the second print head row 3157 deposits at least one of the materials 3114, 3115 on at least one pixel positioned along the build area 3120. In this instance, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are in a default position relative to one another (see
Referring now to
In response to determining that the printing assembly 3150 is not positioned at the translated position 3253, the control system 3010 transmits a signal to the first actuator assembly 3102 to continue translating the printing assembly 3150 across the build area 3120 at step 3602; releasing the first material 3114 from the plurality of print heads 3156 of the first print head row 3155; and releasing the second material 3115 from the plurality of print heads 3156 of the second print head row 3157.
Alternatively, in response to determining that the printing assembly 3150 is positioned at the translated position 3253, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the printing head 3154 to terminate release of the first material 3114 and the second material 3115 from the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157, respectively. Additionally and/or simultaneously, the control system 3010 transmits a signal to the first actuator assembly 3102 to terminate movement of the printing assembly 3150 along the working axis 3116.
Still referring to
Referring to
Referring back to
Referring back to
Accordingly, the first material 3114 is transferred from the first fluid reservoir 3110 to the print heads 3156 of the first print head row 3155 and deposited onto the build area 3120 through the plurality of jet nozzles 3158 as the printing assembly 3150 moves across the build area 3120 in the second pass. The second material 3115 is transferred from the second fluid reservoir 3112 to the print heads 3156 of the second print head row 3157 and deposited onto the build area 3120 through the plurality of jet nozzles 3158 as the printing assembly 3150 moves across the build area 3120 in the second pass. As seen in
Although the present example of the exemplary method 3600 depicts and describes the printing assembly 3150 of the apparatus 3100 being initially positioned at the home position 3151 prior to moving to the translated position 3253, and the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 being arranged in the default position prior to moving to a plurality of actuated positions, it should be understood that in other embodiments the printing assembly 3150 may initially be positioned at the translated position 3253 and the plurality of print heads 3156 of the print head rows 3155, 3157 arranged in a position other than the default position without departing from the scope of the present disclosure. Moreover, it should be understood that the exemplary method 3600 described and shown herein may be performed by various other printing assemblies other than the printing assembly 3150, such as, for example, the three-row printing assembly described above. It should further be understood that in some embodiments one or more steps of the method 3600 described above may be adjusted, varied, and/or omitted entirely, including but not limited to steps of releasing materials from the plurality of jet nozzles 3158 onto the plurality of pixels of the build area 3120, determining whether the printing assembly 3150 is at the translated position 3253; ceasing material release from the plurality of jet nozzles 3158, ceasing movement of the printing assembly 3150, and/or the like.
Referring now to the flow diagram of
At step 3702, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the first actuator assembly 3102 to translate the printing assembly 3150 across the build area 3120 in a first pass. In particular, the printing assembly 3150 translates across the rail 3104 of the apparatus 3100 and along the working axis 3116, thereby moving the printing head 3154 over the build area 3120 in the +X direction of the coordinate axes of the figures. The computer readable and executable instructions, when executed by the processor of the control system 3010, further transmits a signal to the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 to release a material from the plurality of jet nozzles 3158 of each, as the printing head 3154 moves over the build area 3120. The material (e.g., the binder material 3050, the first material 3114, the second material 3115, and the like) is transferred to the printing head 3154 and deposited onto the build area 3120 through the plurality of jet nozzles 3158 of the plurality of print heads 3156 in both the first print head row 3155 and the second print head row 3157.
In the present example, the plurality of print heads 3156 of the first print head row 3155 and the plurality of print heads 3156 of the second print head row 3157 deposit the same material (e.g., the binder material 3050, the first material 3114, the second material 3115, and the like) along the build area 3120. Accordingly, each of the plurality of jet nozzles 3158 of the plurality of print heads 3156 from the first print head row 3155 and the second print head row 3157 jet the material on at least one pixel positioned along the build area 3120. In this instance, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are in a default position (see
Still referring to
It should be understood that the first print head row 3155 and/or the second print head row 3157 of the plurality of print heads 3156 are continuously actuated (i.e. translated) to the plurality of positions at step 3704 as the printing assembly 3150 moves across the build area 3120 and releases the material thereon along the plurality of pixels of the build area 3120. Accordingly, the first print head row 3155 and/or the second print head row 3157 is positioned in a plurality of arrangements relative one another at step 3704 during the material deposition process. In the present example, the printing assembly 3150 includes an actuator 3160 coupled to each of the first print head row 3155 and the second print head row 3157 of print heads 3156, respectively, such that both print head rows 3155, 3157 are movable relative one another and relative the support bracket 3152 of the printing assembly 3150. In this instance, the plurality of jet nozzles 3158 of each of the plurality of print heads 3156 defining the first print head row 3155 and the second print head row 3157 are continuously repositioned from a default position to an actuated position that differs from the default position by at least some incremental distance (e.g., incremental distances A-G of
It should be understood that in some embodiments movement of the first print head row 3155 and the second print head row 3157 relative one another, and relative to a prior position of said print head rows 3155, 3157 during the current pass of the printing assembly 3150 over the build area 3120, may be arbitrary. In this instance, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the actuators 3160 to move the first print head row 3155 and the second print head row 3157 of the plurality of print heads 3156 to a plurality of randomly generated positions relative one another. In this embodiment, a jetting redundancy by the printing assembly 3150 is provided through the continuous repositioning of the plurality of print heads 3156 of each print head row 3155, 3157 in an uncalculated manner such that the plurality of pixels along the build area 3120 are effectively aligned with a plurality of jet nozzles 3158 during a current pass of the printing assembly 3150.
In other embodiments, movement of the first print head row 3155 and the second print head row 3157 relative one another, and relative to a prior position of said print head rows 3155, 3157 during the current pass of the printing assembly 3150, may be predetermined by the control system 3010. In this instance, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the actuators 3160 to move the first print head row 3155 and/or the second print head row 3157 of the plurality of print heads 3156 to a plurality of measured positions that vary relative to a prior position of the print head rows 3155, 3157 during said current pass. In this embodiment, a jetting redundancy by the printing assembly 3150 is provided through the continuous repositioning of the plurality of print heads 3156 of each print head row 3155, 3157 in a calculated manner such that the plurality of pixels along the build area 3120 are effectively aligned with a plurality of jet nozzles 3158 during a current pass of the printing assembly 3150.
The control system 3010 may determine the calculated positions of the plurality of print heads 3156 of the print head rows 3155, 3157 through various systems, such as, for example, a camera image, a sensor output, a calibration pattern, and the like. In either instance, the continuous movement of the first print head row 3155 and the second print head row 3157 of print heads 3156 during the first pass of the printing assembly 3150 provides an enhanced, material jetting redundancy of the manufacturing process by increasing a reliability that a complete resolution of each of the plurality of pixels on the build area 3120 receives an adequate deposition of material thereon from more than one jet nozzle 3158.
Still referring to
Alternatively, in response to determining that the printing assembly 3150 is positioned at the translated position 3253, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the printing head 3154 to terminate release of the material from the plurality of jet nozzles 3158 of the plurality of print heads 3156. Additionally and/or simultaneously, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the first actuator assembly 3102 to terminate movement of the printing assembly 3150 along the working axis 3116. With the printing assembly 3150 positioned at the translated position 3253, the plurality of pixels positioned along the build area 3120 have received the material from more than one jet nozzle 3158 during the first pass of the printing assembly 3150 over the build area 3120 due to the continuous movement of the first print head row 3155 and the second print head row 3157 during said first pass.
Still referring to
Alternatively, in response to determining that additional layers of material are to be deposited by the apparatus 3100 at step 3706, the computer readable and executable instructions, when executed by the processor of the control system 3010, returns the method 3700 to step 3702 and repeats the steps shown and described herein for the second pass. In this instance the instructions by the processor of the control system 3010 causes the apparatus 3100 to repeat the steps described in detail above until the three-dimensional model to be printed by the apparatus 3100 is complete and no additional layers are to be printed at step 3706.
Although the present example of the exemplary method 3700 depicts and describes the printing assembly 3150 of the apparatus 3100 being initially positioned at the home position 3151 prior to moving to the translated position 3253, and the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 being arranged in the default position prior to moving to a plurality of actuated positions, it should be understood that in other embodiments the printing assembly 3150 may initially be positioned at the translated position 3253 and the plurality of print heads 3156 of the print head rows 3155, 3157 arranged in a position other than the default position without departing from the scope of the present disclosure. Moreover, it should be understood that the exemplary method 3700 described and shown herein may be performed by various other printing assemblies other than the printing assembly 3150, such as, for example, the three-row printing assembly described above. It should further be understood that in some embodiments one or more steps of the method 3700 described above may be adjusted, varied, and/or omitted entirely, including but not limited to steps of releasing materials from the plurality of jet nozzles 3158 onto the plurality of pixels of the build area 3120, determining whether the printing assembly 3150 is at the translated position 3253, ceasing material release from the plurality of jet nozzles 3158, ceasing movement of the printing assembly 3150, and/or the like.
Referring now to the flow diagram of
At step 3802, the computer readable and executable instructions, when executed by the processor of the control system 3010, receives an input of a programmable build size for the printing assembly 3150 to employ prior to initiating the material deposition process. As briefly described above, the printing assembly 3150 is configured to dynamically adjust an effective build size of the printing head 3154 in response to moving at least one of the plurality of print heads 3156 defining the first print head row 3155 and/or the second print head row 3157. It should be understood that a build size of the printing head 3154 corresponds to a lateral width (in the +/−Y axes of the coordinate axes of the figures) of a jetting range and/or field of view of the plurality of print heads 3156 disposed therein. A jetting range of the printing head 3154 may be dynamically adjusted (e.g., increased or decreased) by moving the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 relative to one another and the support bracket 3152 of the printing assembly 3150 to a plurality of arrangements (in the +/−Y axes of the coordinate axes of the figures).
For example, a build size and/or width of the printing head 3154 may be relatively minimal by substantially aligning the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 with one another, in the +/−Y axes of the coordinate axes of the figures, such that an overall jetting range of the printing head 3154 (in the +/−Y axes of the coordinate axes of the figures) is minimized. In other words, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are translated in the +/−Y axes of the coordinate axes of the figures to substantially overlap with one another in the +/−X axes of the coordinate axes of the figures. Examples of the printing head 3154 of the printing assembly 3150 including a relatively minimal build size in response to actuating the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 to form an overlap of the plurality of jet nozzles 3158 (in the +/−Y axes of the coordinate axes of the figures) is shown in
By way of further example, a build size and/or width of the printing head 3154 may be relatively great by substantially offsetting the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 with one another, in the +/−Y axes of the coordinate axes of the figures, such that an overall jetting range of the printing head 3154 (in the +/−Y axes of the coordinate axes of the figures) is maximized. In other words, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are translated in the +/−Y axes of the coordinate axes of the figures to be substantially offset with one another in the +/−X axes of the coordinate axes of the figures. Examples of the printing head 3154 of the printing assembly 3150 including a relatively maximum build size in response to actuating the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 to laterally extend the plurality of jet nozzles 3158 (in the +/−Y axes of the coordinate axes of the figures) is shown in
Still referring to
In the present example, the plurality of print heads 3156 of the first print head row 3155 and the plurality of print heads 3156 of the second print head row 3157 deposit the same material (e.g., the binder material 3050, the first material 3114, the second material 3115, and the like) along the build area 3120. Accordingly, each of the plurality of jet nozzles 3158 of the plurality of print heads 3156 from the first print head row 3155 and the second print head row 3157 jet the material on at least one pixel positioned along the build area 3120. In this instance, the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157 are in an actuated position relative one another, in accordance with the inputted build size of step 3802, as the printing assembly 3150 begins to deposit the material onto the build area 3120 of the apparatus 3100.
Still referring to
Alternatively, in response to determining that the printing assembly 3150 is positioned at the translated position 3253, the computer readable and executable instructions, when executed by the processor of the control system 3010, transmits a signal to the printing head 3154 to terminate release of the material from the plurality of jet nozzles 3158 of the plurality of print heads 3156 of the first print head row 3155 and the second print head row 3157. Additionally and/or simultaneously, the control system 3010 transmits a signal to the first actuator assembly 3102 to terminate movement of the printing assembly 3150 along the working axis 3116 by ceasing actuation of the first actuator assembly 3102. With the printing assembly 3150 positioned at the translated position 3253, the plurality of pixels positioned along the build area 3120 have received material thereon from at least the first print head row 3155 or the second print head row 3157 during the first pass of the printing assembly 3150 over the build area 3120 in the +X direction of the coordinate axes.
Still referring to
In response to the control system 3010 of the apparatus 3100 determining that a different build size is to be effectively employed by the printing assembly 3150 at step 3812, the instructions executed by the processor of the control system 3010 returns the method 3800 to step 3802 and repeats the steps shown and described herein for the second pass determine a new effective build size of the printing assembly 3150. Alternatively, in response to the control system 3010 of the apparatus 3100 determining that an identical build size is to be effectively employed by the printing assembly 3150 at step 3812, the executed by the processor of the control system 3010 returns the method 3800 to step 3806 and repeats the steps shown and described herein for the second pass. In either instance, the instructions causes the apparatus 3100 to repeat the steps described in detail above until the three-dimensional model to be printed by the apparatus 3100 is complete and no additional layers of material are to be deposited at step 3808.
Although the present example of the exemplary method 3800 depicts and describes the printing assembly 3150 of the apparatus 3100 being initially positioned at the home position 3151 prior to moving to the translated position 3253, and the plurality of print heads 3156 of the first print head row 3155 and/or the second print head row 3157 being arranged to define a selected build size prior to the printing assembly 3150 moving across the build area 3120, it should be understood that in other embodiments the printing assembly 3150 may initially be positioned at the translated position 3253 and the build size of the printing assembly 3150 employed during and/or after the printing assembly 3150 moves across the build area 3120 during a first pass. Additionally, the plurality of print heads 3156 of the print head rows 3155, 3157 may be arranged in a plurality of other positions other than those shown and described in
Referring now to the flow diagram of
Referring to
The slicing engine may define a plurality of pixels and/or sub-pixel centers. Once the layers, pixels, and/or sub-pixel centers are defined, a slicing engine may begin determining the amount of binder to deposit within each pixel within each layer. The predetermined amount of binder and the pixels defining a binder-receiving surface of a layer are combined to define a design deposition pattern for the layer of the component to be built. The build instructions may include a deposition pattern (e.g., 3125, 3126, or 3127,
At block 3904, the electronic control unit of the apparatus may actuate the printing head position control assembly (e.g., the first actuator assembly 3102, the second actuator assembly 3103, and other components) in accordance with the received build instructions. For example, the electronic control unit transmits one or more control signals that cause the first actuator assembly 3102 and/or the second actuator assembly 3103 to perform a movement defined by the build instructions. As described above, the actuators may include, without limitation, a worm drive actuator, a ball screw actuator, a pneumatic piston, a hydraulic piston, an electro-mechanical linear actuator, or the like. As such, a control signal from the electronic control unit may cause a motor associated with a worm drive actuator or a ball screw actuator to energize for a period of time or until a number of revolutions are completed to cause the predetermined motion defined by the build instructions. In some instances, the first actuator assembly 3102 and/or the second actuator assembly 3103 may include a position sensor (e.g., 3102a and/or 3103a) that provides the electronic control unit with position information in a feedback control signal such that the electronic control unit may track the position of the printing assembly 3150 in response to the provided control signals. In some instances the electronic control unit may make adjustments to the control signal provided to the first actuator assembly 3102 and/or the second actuator assembly 3103 based on the position information provided by the position sensor (e.g., 3102a and/or 3103a). In embodiments, the position sensor (e.g., 3102a and/or 3103a) may be an encoder, an ultrasonic sensor, a light based sensor, a magnetic sensor, or the like embedded in or coupled to the first actuator assembly 3102 and/or the second actuator assembly 3103.
At block 3906, the electronic control unit causes the printing assembly 3150 including at least one printing head 3154 to traverse the build area 3120 in a first pass trajectory along the longitudinal axis in a first direction. Moreover, the electronic control unit causes select ones of the plurality of jet nozzles 3158 to dispense one or more drops of binder or other material onto the build area 3120. The electronic control unit is communicatively coupled to one or more of the plurality of print heads 3156 such that control signals generated by the electronic control unit cause the jet nozzles associated with the print heads 3156 to dispense binder or other material at predefined locations in predefined amounts as the printing assembly 3150 traverses the build area 3120 as defined by a deposition pattern for a layer of powder of a build (e.g., 3125,
Once a pass of the build area is completed by the printing assembly 3150, the electronic control unit, based on the build instructions, determines whether indexing of the printing assembly 3150 along the latitudinal axis is required, at block 3908. If indexing is required, (“YES” at block 3908) the electronic control unit transmits a control signal to the second actuator assembly 3103 to index the printing assembly 3150 a predefined amount (e.g., an index distance), for example, greater than zero and less than a jet-spacing (d) (or any integer multiple of the fractional jet-spacing (d) thereof) as defined by the build instructions, at block 3910. Referring to
The method 3900 of
As described above, the electronic control unit is communicatively coupled to one or more of the plurality of print heads 3156 such that control signals generated by the electronic control unit cause the jet nozzles associated with the print heads 3156 to dispense binder or other material at predefined locations in predefined amounts as the printing assembly 3150 traverses the build area 3120 as defined by a deposition pattern (e.g., 3125,
If indexing of the printing assembly is not required, (“NO” at block 3908), then the method 3900 proceeds to block 3912, where the printing assembly 3150 may move across the build area in a second pass in a second direction opposite the first direction along the longitudinal axis as described herein. The method 3900 depicted in
In some embodiments, either independent of or in conjunction with the method 3900 depicted and described with reference to
Referring to
At block 31006, the electronic control unit causes the printing assembly 3150 including at least one print head 3156 and jet nozzle 3158 to traverse the build area 3120 in a first pass trajectory along the longitudinal axis in a first direction. Moreover, the electronic control unit causes select ones of the plurality of jet nozzles 3158 to dispense one or more drops of binder or other material onto the build area 3120. The electronic control unit is communicatively coupled to one or more of the plurality of print heads 3156 such that control signals generated by the electronic control unit cause the jet nozzles 3158 associated with the print heads 3156 to dispense binder or other material at predefined locations in predefined amounts as the printing assembly 3150 traverses the build area 3120 as defined by a deposition pattern for a layer of powder of a build (e.g., 3125,
Accordingly, the electronic control unit, at block 31008, determines whether an index of the printing assembly is prescribed by the build instructions and the corresponding predefined random index distance. If no index is prescribed at the completion of a pass of the printing assembly 3150 over the build area 3120, (“NO” at block 31008), then the method advances to block 31012. If indexing is prescribed at the completion of a pass of the printing assembly 3150 over the build area 3120, (“YES” at block 31008), then the method advances to block 31010. At block 31010, the electronic control unit transmits a control signal to the second actuator assembly 3103 to index the printing assembly 3150 a predefined amount (e.g., the predefined random index distance), for example, a predefined integer multiple of a jet-spacing (d) such that a first jet nozzle 3158 of the plurality of jet nozzles 3158 that corresponds to a first trajectory assigned by the build instructions during one pass of the printing assembly along the longitudinal axis is moved to corresponds to a second trajectory and another jet nozzle 3158 corresponds to the first trajectory for a subsequent pass. Referring to
The method 31000 of
Referring now to
The method described herein may be performed by an electronic control unit or computing device 3015 implementing a slicing engine and/or other motion control generating code for building a component with the apparatus 3100. Referring in particular to
At block 31112, the slicing engine determines how to treat each of the vertically adjacent voxels with respect to the amount of binder that should be applied. The determination may be made based on whether a series of vertically adjacent portions is less than, equal to, or greater than a predetermined thickness threshold. The thickness threshold is predetermined based on characteristics of the binder, powder, build speed, component features, whether a curing energy is applied, the amount of time the curing energy is applied, the energy at which it is applied and/or other aspects of the build. Referring back to block 31112, if the quantity of vertically adjacent portions 3222 is less than or equal to a predetermined thickness threshold, then the method 31100 advances to block 31114. On the other hand, at block 31112, if the quantity of vertically adjacent voxels is not less than a predetermined thickness threshold, then the method 31100 advances to block 31116.
At block 31114, the slicing engine assigns a predetermined amount of binder per portion for deposition within the first portion and each vertically adjacent portion. If the thickness threshold 3240 is three, as depicted for example in
It should be understood that steps of the aforementioned processes may be omitted or performed in a variety of orders while still achieving the object of the present disclosure. The functional blocks and/or flowchart elements described herein may be translated onto machine-readable instructions. As non-limiting examples, the machine-readable instructions may be written using any programming protocol, such as: descriptive text to be parsed (e.g., such as hypertext markup language, extensible markup language, etc.), (ii) assembly language, (iii) object code generated from source code by a compiler, (iv) source code written using syntax from any suitable programming language for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. Alternatively, the machine-readable instructions may be written in a hardware description language (HDL), such as logic implemented via either a field programmable gate array (FPGA) configuration or an application-specific integrated circuit (ASIC), or their equivalents. Accordingly, the functionality described herein may be implemented in any conventional computer programming language, as pre-programmed hardware elements, or as a combination of hardware and software components.
Based on the foregoing, it should be understood that a printing assembly, includes a support bracket and a first print head row comprising a first plurality of print heads that are sequentially spaced apart from one another in a direction that is transverse to a working axis of the printing assembly. Each of the first plurality of print heads includes a plurality of jet nozzles thereon. The printing assembly further includes a second print head row comprising a second plurality of print heads sequentially spaced apart from one another in the direction transverse to the working axis. Each of the second plurality of print heads includes a plurality of jet nozzles, and the first print head row and the second print head row are spaced apart along the working axis. The printing assembly further includes an actuator coupled to a first print head of the first plurality of print heads, and is configured to move the first print head relative to the support bracket in the direction transverse to the working axis.
It is also understood that a manufacturing apparatus may include a printing head having a plurality of jets spaced apart from one another in a direction transverse to a longitudinal axis, where a distance from a first jet to a second jet positioned adjacent the first jet of the plurality of jets defines a jet-spacing. The manufacturing apparatus may further include a printing head position control assembly having a first actuator assembly configured to move the printing head along the longitudinal axis and a second actuator assembly configured to move the printing head along a latitudinal axis and an electronic control unit communicatively coupled to the printing head position control assembly. The electronic control unit may be configured to cause select ones of the plurality of jets to dispense one or more drops of binder while the printing head traverses a first pass trajectory along the longitudinal axis in a first direction, index the printing head to a second pass trajectory along the latitudinal axis by an index distance greater than zero and less than the jet-spacing, and cause select ones of the plurality of jets to dispense one or more drops of binder while the printing head traverses the second pass trajectory along the longitudinal axis in a second direction opposite the first direction.
In further embodiments, the manufacturing apparatus may include at least one printing head comprising a plurality of jets spaced apart from one another in a direction transverse to a longitudinal axis, where a distance from a first jet to a second jet positioned adjacent the first jet of the plurality of jets defines a jet-spacing. A printing head position control assembly of the manufacturing apparatus includes a first actuator configured to move the printing head along the longitudinal axis and a second actuator configured to move the printing head along a latitudinal axis. An electronic control unit communicatively coupled to the printing head position control assembly is configured to: cause select ones of the plurality of jets to dispense one or more drops of binder to a powder layer in a deposition pattern defined by a slicing engine as the printing head traverses along the longitudinal axis applying binder, where the first jet of the plurality of jets corresponds to a first trajectory assigned by the slicing engine. The electronic control unit may further index the printing head by an integer number of pixels along the latitudinal axis such that the first jet corresponds to a second trajectory and another jet corresponds to the first trajectory assigned by the slicing engine, and cause the indexed printing head to traverse along the longitudinal axis and apply binder to the powder layer in the deposition pattern defined by the slicing engine.
In yet further embodiments, it is understood that a manufacturing apparatus may include a printing head comprising a plurality of jets spaced apart from one another in a direction transverse to a longitudinal axis, a printing head position control assembly having a first actuator configured to move the printing head along the longitudinal axis; and an electronic control unit communicatively coupled to the printing head position control assembly. The electronic control unit is configured to cause select ones of the plurality of jets to dispense a predetermined volume of binder to a powder layer in a deposition pattern defined by a slicing engine as the printing head traverses the longitudinal axis applying binder, where an amount of binder dispensed in a first portion of powder in a first layer is less than the amount of binder dispensed in a portion of powder in a second layer located above the first portion of powder in the first layer.
As noted herein, the printing assembly 3150 and methods for using the printing assembly 3150 may be used in conjunction with one or more of the embodiments of the additive manufacturing apparatuses described herein, including the method of operating an additive manufacturing apparatus as described herein with respect to
Turning now to
The cleaning station 110 may comprise a cleaning station vessel 4314 positioned proximate at least one binder purge bin 4302. As shown in
Further as shown, the cleaning station vessel 4314 is a container which includes a wet wipe cleaner section 4304, a dry wipe cleaner section 4306, and a capping section 4308. In various embodiments, the wet wipe cleaner section 4304, the dry wipe cleaner section 4306, and the capping section 4308 are sections of a cleaning station vessel 4314 containing a volume of cleaning fluid. The wet wipe cleaner section 4304 applies cleaning fluid to the print head, specifically, a faceplate of the print head. The dry wipe cleaner section 4306, which in some embodiments is downstream of the wet wipe cleaner section 4304, removes excess liquid (e.g., cleaning fluid and contaminants) from the print head in advance of binder jetting. The capping section 4308, which may be also considered an idle section, is a location where the print head may be temporarily placed in advance of binder jetting. In embodiments, the capping section 4308 supplies cleaning fluid to the print head faceplate to prevent binder from drying on the print head. Without being limited to theory, maintaining the wet wipe cleaner section 4304, the dry wipe cleaner section 4306, and the capping section 4308 within a single cleaning station vessel 4314 is highly advantageous as it streamlines cleaning fluid management by eliminating the need to control three separate cleaning station vessels. In this embodiment, cleaning fluid maintenance is limited to a single cleaning station vessel 4314.
In embodiments, the cleaning station vessel 4314 includes at least one movable wall 4316 extending vertically upward (e.g., +/−Z) from the cleaning station vessel 4314 and in a direction parallel to a direction of movement of the print head 150 through the cleaning station 110 (e.g., +/−X). When included, the movable wall 4316 redirects cleaning fluid into the cleaning station vessel 4314. For example, cleaning fluid that is splashed, such as from the movement of the wet wipe member 4310 and/or the dry wipe member 4312 into and out of the cleaning station vessel 4314, may be redirected back into the cleaning station vessel 4314 rather than being lost into the environment (e.g., onto the floor). In embodiments, the movable wall 4316 may be coupled to one or more actuators to enable movement of the wall. For example, the movable wall 4316 may be moved in the +Z direction when the print head 150 enters the cleaning station 110, and in the −Z direction when the print head 150 leaves the cleaning station 110. Additionally or alternatively, the movable wall 4316 may be moved along the +/−X direction through the cleaning station 110 along a path parallel to the path of the print head 150.
In embodiments, the movable wall 4316 is coupled to the wall of the cleaning station vessel 4314 through a guide slot (not shown), and is movable within the guide slot. Accordingly, in the event that the print head 150 or another item contacts the movable wall 4316, the movable wall 4316 will yield (e.g., move) rather than causing damage to the print head 150 or other part of the additive manufacturing apparatus 100. It is contemplated that the movable wall 4316 could be coupled to the wall of the cleaning station vessel 4314 in other ways, including through the use of magnetic mounts, bolts, or slotted holes, for example.
In embodiments, the cleaning station vessel 4314 is in fluid communication with an overflow vessel 4318, as shown in
In the embodiments described herein, the print head 150 may deposit the binder material 500 on a layer of build material 400 distributed on the build platform 120 through an array of nozzles 172 located on the underside of the print head 150 (i.e., the surface of the print head 150 facing the build platform 120). In one or more embodiments, the nozzles 172 may be piezoelectric print nozzles and, as such, the print head 150 is a piezo print head. In alternative embodiments, the nozzles 172 may be thermal print nozzles and, as such, the print head 150 is a thermal print head.
In general, after the print head 150 has deposited the binder material 500 on the layer of build material 400 positioned on the build platform 120 (
Various suitable embodiments are contemplated for the wet wipe cleaner section 4304. As shown in
Referring now to
Although the wet wipe member 4310 is described in various embodiments as including at least one wiper blade 4406, in embodiments, the wet wipe member 4310 does not include wiper blades, as shown in
A fluid channel 4408 extends horizontally from a first end 4410 of the wet wiper body 4401 to a second end 4412 of the wet wiper body 4401, as shown in
As shown in
In embodiments, each of the wiper blades 4406a has the same vertical (e.g., +/−Z) position as the other blades 4406b, as shown in
As shown in
In various embodiments, the cleaning fluid is provided to the cleaning manifold 4414 through a plurality of cleaning fluid inlets 4416 that are fluidly coupled to a cleaning fluid reservoir or cleaning fluid management system, described in greater detail below. The plurality of cleaning fluid inlets 4416 may be, for example, fluid conduits that extend vertically upward through the bottom side 4404 of the wet wiper body 4401. However, in embodiments, the plurality of cleaning fluid inlets 4416 additionally or alternatively extend from a side 4403 of the wet wiper body 4401 adjacent to the top side 4402 and the bottom side 4404 of the wet wiper body 4401. The plurality of cleaning fluid inlets 4416 are operable to receive the cleaning fluid and provide the cleaning fluid to the cleaning manifold 4414. The cleaning fluid inlets 4416 are in fluid communication with the fluid port 4407 through the cleaning manifold 4414 such that cleaning fluid enters the cleaning manifold 4414 through the cleaning fluid inlets 4416 and exits the cleaning manifold 4414 through the fluid port 4407.
As stated above, the wet wipe member 4310 is coupled to one or more actuators 4311 which are operable to raise or lower the wet wipe member 4310 into and out of the volume of the cleaning fluid. For example, the wet wipe member 4310 may be actuated just prior to the print head 150 moving to the wet wipe cleaner section 4304 such that the wet wipe member 4310 is raised out of the volume of the cleaning fluid and contacts the print head 150 as it is moved through the wet wipe cleaner section 4304. In various embodiments, the wet wipe member 4310 is actuated as close to the time that it will make contact with the print head 150 as possible, so as to ensure that the wiper blades 4406 are wet with cleaning fluid, although it is contemplated that some period of time may pass between the wet wipe member 4310 being raised out of the volume of the cleaning fluid and making contact with the print head 150.
As another example, the wet wipe member 4310 may be actuated after the print head 150 has moved to the dry wipe cleaner section 4306 such that the wet wipe member is lowered into the volume of the cleaning fluid. The lowering of the wet wipe member into the cleaning fluid may wash away contaminants on the surface of the wiper blades 4406 and clean the wet wipe member 4310, thereby reducing the likelihood that the wet wipe member 4310 will introduce contaminants to the print head 150. Additional details on the actuation of wet wipe member 4310 embodiments are described below.
In various embodiments, the cleaning manifold 4414 fills with the cleaning fluid and feeds the fluid channel 4408, which fills from the bottom of the fluid channel 4408. In embodiments in which the fluid channel 4408 is positioned between the wiper blades 4406, the cleaning fluid forms a pool of cleaning fluid between the wiper blades 4406. In one or more embodiments, the cleaning fluid flows over the sides of the fluid channel 4408 and into overflow drains, which return the cleaning fluid to the cleaning manifold 4414. In further embodiments, the cleaning fluid is fed through the wet wipe member 4310 continuously during operation of the additive manufacturing apparatus. After the wet wipe member applies liquid to the print head, the liquid then overflows back into the cleaning station vessel 4314. As described more below, within the cleaning station vessel 4314, there is a drain 4824 (see
Accordingly, when the wet wipe member 4310 is actuated, cleaning fluid is supplied to the print head 150 to dissolve contaminants while the wiper blades 4406 mechanically remove contaminants. While the cleaning fluid may dissolve the contaminants in some cases, the contaminants may also be considered as mixed or suspended within the cleaning fluid. The cleaning manifold 4414 and the fluid channel 4408 ensure that cleaning fluid can be directly applied to the print head 150 during cleaning while compensating for any delay that may result from the use of pumps in the fluid management system, as will be discussed in greater detail below. In particular, the cleaning manifold 4414 and the fluid channel 4408 provide a local reservoir of cleaning fluid that can be used even when the pumps are not actively providing cleaning fluid to the wet wipe member 4310.
In the embodiment depicted in
Similar to the wet wipe cleaner section 4304, various suitable embodiments are contemplated for the dry wipe cleaner section 4306. Referring to the embodiments depicted in
An embodiment of the dry wipe member 4312 is depicted in
As described above, each of the plurality of dry wiper blades 4502 has an overlap of at least part of its length l with the length l of an adjacent dry wiper blade 4502 in a direction orthogonal to the longitudinal axis LA. In embodiments, each of the plurality of dry wiper blades 4502 has an overlap of at least 30% of its length l with the length of an adjacent dry wiper blade in a direction orthogonal to the longitudinal axis LA. For example, in some embodiments, each of the plurality of dry wiper blades 4502 may have an overlap of from 30% to 70% of its length with the length of an adjacent dry wiper blade in a direction orthogonal to the longitudinal axis LA. Such an arrangement enables the dry wipe member 4312 to contact the print head 150 with at least two blades 4516 over the entire length of the print head 150. Other arrangements are contemplated, such as arrangements that enable the dry wipe member 4312 to contact the print head 150 with three or more blades 4516 over the entire length of the print head 150. Without being bound by theory, it is believed that because the dry wiper blades are angled with respect to the longitudinal axis LA and their lengths overlap with adjacent dry wiper blades, the dry wipe member 4312 imparts less drag on the print head 150 as it wipes cleaning fluid from the print head 150 and is thereby more effective in wiping off the cleaning fluid. Additionally, the use of the array of angled dry wiper blades may result in the cleaning fluid being drained away from the print head 150 in less time compared to a single wiper blade extending along the longitudinal axis LA.
In embodiments, each of the blades 4516 has the same vertical (e.g., +/−Z) position as the other blades 4516. Accordingly, all of the blades 4516 has the same engagement distance with the print head 150 during wiping operations. As is known in the art, the “engagement distance” refers to the amount by which the vertical position of the print head 150 and the vertical position of an undeflected blade 4516 overlap. However, as shown in
In some embodiments, the wiper mounting member 4501 includes channels 4504, as shown in
As depicted in
In further embodiments, the dry wipe member 4312 is coupled to two actuators (e.g., actuators 4313) which are operable to raise or lower the dry wipe member 4312 into and out of the volume of the cleaning fluid. For example, the dry wipe member 4312 may be actuated such that the dry wipe member 4312 is raised out of the volume of the cleaning fluid with sufficient time to allow the cleaning fluid to drain away from the dry wiper blades 4502. The dry wipe member 4312 contacts the print head 150 as it is moved through the dry wipe cleaner section 4306 to remove cleaning fluid, contaminants and other debris from the print head 150 after the print head 150 is cleaned by the wet wipe member 4310.
As another example, the dry wipe member 4312 may be actuated after the print head 150 has moved to the capping section 4308 or the build platform 120 such that the dry wipe member 4312 is lowered into the volume of the cleaning fluid. The lowering of the dry wipe member 4312 into the cleaning fluid may wash away contaminants on the surface of the dry wiper blades 4502 and clean the dry wipe member 4312, thereby reducing the likelihood that the dry wipe member 4312 will introduce (or reintroduce) contaminants to the print head 150. In some embodiments, the dry wipe member 4312 is lowered into the volume of the cleaning fluid for a period of time sufficient to rinse the dry wipe member 4312, and then is raised out of the volume of the cleaning fluid until it has been used to wipe the print head 150 again.
As described with reference to
An example embodiment of a capping section 4308 is shown in greater detail in
The sponge 4702 can be formed of any suitable material capable of absorbing and holding the cleaning fluid for a predetermined period of time. In some embodiments, the sponge 4702 may be made from cellulose wood fibers or foamed plastic polymers. In some particular embodiments, the sponge 4702 may be made from a silicone material, such as a foamed silicone, a polyurethane, a polyimide, or combinations thereof.
The sponge support 4704 can be a metal or plastic plate sized to support the sponge 4702. In some embodiments, the sponge 4702 may be coupled to the sponge support 4704, such as through the use of an adhesive layer between the sponge 4702 and the sponge support 4704, or an attachment member, such as a bolt, screw, or other mechanism to attach the sponge 4702 to the sponge support 4704. In some embodiments, the sponge 4702 may be removably coupled to the sponge support 4704 such that the sponge 4702 can be easily replaced without also replacing the sponge support 4704 and actuator 4706.
As shown in
The sponge support 4704 is coupled to an actuator 4706 that is operable to raise and lower the sponge 4702 within the cleaning fluid. The actuator 4706 may be a linear actuator, a rotary actuator, a pneumatic actuator, an electric actuator, or any other suitable type of actuator selected based on the particular embodiment. Although depicted in
In the embodiment shown in
In various embodiments, when the print head 150 is located at the capping section 4308 of the cleaning station 110, the sponge 4702 is at least partially submerged in the cleaning fluid. In other words, some or all of the sponge 4702 extends below the fluid level 4600 of the cleaning fluid to enable the sponge 4702 to be constantly absorbing cleaning fluid from the cleaning station 110. In some such embodiments, at least a portion of the sponge 4702 extends above the fluid level 4600 of the cleaning fluid such that the sponge 4702 is in contact with the print head 150 without submerging the print head 150 in the cleaning fluid. In embodiments, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or even 99% of the volume of the sponge 4702 may extend above the fluid level 4600 of the cleaning fluid.
In practice, to clean the print head 150, cleaning fluid is applied to the print head 150 using the wet wipe member 4310 by passing the print head 150 through the wet wipe cleaner section 4304. Then, cleaning fluid is removed from the print head 150 using the dry wipe member 4312 by passing the print head 150 through the dry wipe cleaner section 4306. Then, when the print head 150 will be idle or the additive manufacturing apparatus 100 is undergoing maintenance, the print head 150 is moved to the capping section 4308 and into contact with the sponge 4702 that is at least partially submerged in the cleaning fluid. In other embodiments (not shown), it is not required for the sponge to be submerged in the cleaning fluid. The sponge 4702 is maintained in contact with the print head 150 while the print head 150 is idle or the additive manufacturing apparatus 100 is undergoing maintenance, thereby reducing evaporation of binder material in the nozzles of the print head 150, preventing the curing of the binder material around the print head 150, and the like.
Although described above as including a sponge 4702, in some embodiments, the cover 4701 of the capping section 4308 is a cap 4710, as shown in
As with the sponge 4702, the cap 4710 is coupled to an actuator 4706 that is operable to raise and lower the cap 4710 within the cleaning fluid. The actuator 4706 may be a linear actuator, a rotary actuator, a pneumatic actuator, an electric actuator, or any other suitable type of actuator selected based on the particular embodiment. In the embodiment shown in
In embodiments, the actuator 4706 enables the height of the cap 4710 to be adjusted relative to the print head 150. Accordingly, the cap 4710 may be positioned to contact the print head 150 with fluid contained within the cap 4710, or the cap 4710 may be positioned to cap the print head 150 such that the face of the print head 150 is not contacted by the fluid.
In embodiments, the cap 4710 may further include one or more gaskets or seals 4712 to create a seal between the cap 4710 and the print head 150 when the cap 4710 is in use. The creation of a seal may minimize or even eliminate evaporation of the cleaning fluid in the cap 4710, the binder material in the print head 150, or both. Moreover, in embodiments, the cap 4710 may include one or more ports 4714 (e.g., inlet and outlet ports) to enable cleaning fluid to be flowed through the cap 4710 during use. Accordingly, the cleaning fluid in the cap 4710 can be replenished or refreshed.
In still other embodiments, the cap 4710 of
In embodiments, as an alternative to a dedicated capping section 4308, the cleaning station vessel 4314 itself may form a cover for the print head. In such embodiments, the cleaning station vessel 4314 is coupled to one or more actuators 4706 to move the cleaning station vessel 4314 in a vertical direction with respect to the print head 150, as shown in
It is further contemplated that, in embodiments, the print head 150 is actuatable in the vertical direction for sealing with the cleaning station vessel 4314. Accordingly, depending on the particular embodiment, one or more of the cleaning station vessel 4314, seals positioned around the perimeter of the cleaning station vessel 4314, and the print head 150 are moved in a vertical direction to enable a seal to be formed between the cleaning station vessel 4314 and the print head 150. As with the previously-described embodiments of the capping section 4308, in embodiments, vertical movement of one or more of the cleaning station vessel 4314, seals positioned around the perimeter of the cleaning station vessel 4314, and the print head 150 is effective to maintain the print head 150 in a non-curing environment.
As has been described herein, various components of the cleaning station 110, including the wet wipe member 4310, the dry wipe member 4312, and the capping section 4308, are configured to move in a vertical (e.g., +/−Z) direction during the cleaning of the print head 150. Although described herein with reference only to the vertical component of the movement, it is contemplated that, in embodiments, the motion of the various components may have motion in other directions in addition to the vertical direction. For example, the motion may be in the form of an arc that includes both horizontal and vertical motion.
In general, the various components of the cleaning station 110 each independently moves between an extended position, in which the component is positioned to engage with or clean the print head 150, and a retracted position, in which the component is submerged within the cleaning fluid within the cleaning station vessel 4314. For example, in embodiments, and with reference to
After being wiped, the print head 150 may be capped in the capping section 4308, or it may proceed to the second binder purge bin 4302, where it is prepared for printing. For example, back pressure may be applied to the print head 150 to equilibrate the print head 150 for printing. In embodiments, the print head 150 then returns to the build platform 120 to deposit binder material onto the powder layer, as described hereinabove.
Alternative orders in the operations of the components of the cleaning station 110 are contemplated. For example, in embodiments, the print head 150 enters the cleaning station 110 from the right hand side of the figure, passing over the second binder purge bin 4302 first. However, as the print head 150 proceeds from right to left, the wet wipe member 4310, the dry wipe member 4312, or the wet wipe member 4310 and the dry wipe member 4312 are in the extended position such that they contact the print head 150 along its path to the first binder purge bin 4302. In such embodiments, this can be a pre-cleaning step to remove surface contaminants prior to the discharging of additional contaminants over the first binder purge bin 4302.
In some embodiments, the wet wipe member 4310 and/or the dry wipe member 4312 may be actuated using a two-stage actuation process to raise and lower the members out of and into the volume of cleaning fluid. Without being bound by theory, the two stage actuation improves cleaning fluid draining from one or both of the dry and wet wipe members, because the cleaning fluid easily flows back into the cleaning station vessel 4314 when only one side of the wipe member is raised above the cleaning fluid level in stage one of the two-stage actuation process. Because the dry wipe member 4312 is directed to removing cleaning fluid, not applying it, ensuring the cleaning fluid is quickly drained from the dry wipe member 4312 in the two stage actuation process is desirable. However, in embodiments, other actuation processes, including single-stage actuation processes, are contemplated and possible.
The embodiment shown in
In
Similarly, the embodiment shown in
In some embodiments, the two-stage actuation process may occur for both the dry wipe members 4312 and the wet wipe members 4310. This embodiment, which is sequentially illustrated in
For example, in embodiments, the actuator 4602b is actuated while the first actuator 4602a is actuated to lower the first and second ends of the wet wipe member 4310 or the dry wipe member 4312 at substantially the same time or during an overlapping time period. In embodiments, such as the embodiment shown in
In embodiments, the first and second actuators 4602a, 4602b (and, accordingly, actuators 4311 and 4313) are electric actuators that are independently operable to raise or lower the corresponding end of the wipe member (e.g., wet wipe member 4310 or dry wipe member 4312) at a plurality of speeds. Accordingly, in embodiments, the first actuator 4602a is actuated to raise a first end of the wipe member at a first speed r1, the second actuator 4602b is actuated to raise a second end of the wipe member at a second speed r2, the second actuator 4602b is actuated to lower the second end of the wipe member at a third speed r3, and the first actuator 4602a is actuated to lower the first end of the wipe member at a fourth speed r4, with at least one of the speeds differing from at least one of the other speeds. For example, the wet wipe member 4310 or the dry wipe member 4312 may be raised at one speed and lowered at another speed (e.g., r1=r2, r3=r4, r4≠3), the first side may be actuated at one speed and the second side may be actuated at another speed (e.g., r1=r4, r2=r3, r1≠3), each actuation may be at a different speed from each other actuation (e.g., r1≠r2≠r3≠r4), or the like. Such actuation can enable, for example, the wet wipe member 4310 to emerge from the cleaning fluid quickly to project cleaning fluid toward the print head and to be submerged in the cleaning fluid to reduce or prevent splashing.
Although the wet wipe member 4310 and the dry wipe member 4312 are described herein as being coupled to two actuators, it is contemplated that in other embodiments, each wipe member may be coupled to a single actuator, or to more than two actuators. Moreover, although the actuators are described herein as being operable to raise and lower the corresponding wipe member, it is contemplated that the actuators may be used in embodiments to cause additional movement of the wipe member. For example, in embodiments in which the actuators are electric actuators, the actuators may be actuated to cause agitation of the wipe member within the cleaning station vessel 4314, to adjust the position of the wipe member within the cleaning station vessel 4314 or with respect to the print head 150, or the like. Electric actuators may further enable “just in time” positioning of the wipe member and/or automatic calibration routines. Other features and advantages are possible, depending on the particular embodiment. Commercially available electric actuators suitable for use include, by way of example and not limitation, ERD electric cylinders available from Tolomatic, Inc. (Hamel, Minn.).
Although it is contemplated in embodiments that the actuators are controlled using a controller, such as control system 5000, in embodiments, one or more additional mechanisms may be included to monitor, set, or limit the motion of the various components of the cleaning station 110. Such mechanisms may be desired, for example, to ensure that the print head 150 is not damaged by the components of the cleaning station 110, while enabling the components to contact the print head 150 as may be necessary to clean the print head 150. Accordingly, in embodiments, an adjustable hard stop 4614 (
In embodiments, a member 4610 is coupled to an actuator 4602 through a motion coupler 4608 to provide or control of the upper position of the member 4610 within the cleaning station 110, and specifically, the cleaning station vessel 4314, as shown in
In the embodiment shown in
Although only one end of the member 4610 is shown in
In addition to, or as an alternative to, the hard stop, in embodiments a gauge 5100 on the underside of the print head 150 is used to vertically align one or more of the components of the cleaning station 110, as shown in
In practice, the print head 150 may be moved over the cleaning station 110, and the member 4610 (e.g., wet wipe member 4310, dry wipe member 4312, or cap 4710) is raised to an initial maximum vertical position. As used herein, the “maximum vertical position” of a member refers to the vertical position of the top edge 5108 of the member 4610 when the member 4610 is at a set maximum vertical height out of the cleaning station vessel 4314. The print head 150 may be positioned directly over the member 4610, or the print head 150 may be located elsewhere over the cleaning station 110 to enable visual comparison of the vertical position of the member 4610 with the gauge 5100. The maximum vertical position Zm of the member 4610 is then adjusted such that the top edge 5108 of the member 4610 is vertically below or lower than the first vertical position Z1. In embodiments, the maximum vertical position Zm of the member 4610 is also greater than or equal to the second vertical position Z2. Put another way, the member 4610 is adjusted such that the maximum vertical position Zm of the member 4610 is Z1>Zm>Z2. Adjustments of the maximum vertical position Zm of the member 4610 can be made by adjusting an adjustable hard stop, as shown and described herein above, adjusting one or more parameters or settings of an actuator coupled to the member 4610, or by other methods that will be known to those of skill in the art, depending on the particular embodiment. In embodiments, adjustments can be made using the gauge 5100 to any or all of the components of the cleaning station 110.
Having described various sections of a cleaning station 110, a fluid management system suitable for providing cleaning fluid to the cleaning station 110 and binder material to the print head 150 will now be described in detail.
Turning to
In general, the binder material pathway includes a binder reservoir 4802 that is in fluid communication with the print head 150 and at least one binder purge bin 4302. As depicted in
Referring again to
In embodiments including multiple binder purge bins, the first binder purge bin is located upstream from the cleaning station vessel 4314 and the second binder purge bin is positioned downstream of the cleaning station vessel 4314 and the dry wipe cleaner section of the cleaning station 110 along a path of the print head 150. In embodiments, the second binder purge bin is positioned upstream of the build area in order to receive binder material ejected (i.e., “spit”) from the print head 150 during preparation of the print head 150 before printing. The second binder purge bin 4302, in some embodiments, can include a non-porous medium (e.g., thermal, pH, hydrochromic or wax paper, cloth media, etc.) for receiving a pattern test printed by the print head 150 when the print head 150 is positioned over the additional binder purge bin 4302. The pattern can be inspected, such as by using a camera configured to capture an image of the pattern, to determine if the printed pattern is suitable. For example, if the printed pattern matches a predetermined reference pattern, the printed pattern may be determined to be suitable. As another example, if the printed pattern differs from the predetermined reference pattern, the printed pattern may be determined to be unsuitable. In such embodiments, the print head may be prevented from supplying binder material to a working surface of the build area, or adjusted prior to supplying the binder material.
The binder material is provided from the binder reservoir 4802 to an ink delivery system 4804 which in turn delivers the binder material to the print head 150. The ink delivery system 4804 enables the separation of storage of the binder material from the print head 150 and allows for the binder material to be replaced or refilled while the additive manufacturing apparatus 100 is actively printing. The print head 150 discharges the binder material through nozzles into, for example, the build area and the binder purge bins 4302.
Binder material discharged into the binder purge bin 4302 passes through an active drain 4806. In the embodiment depicted in
As shown in
In embodiments, the binder material pathway may optionally include an overflow tank 4813 fluidly coupled to the overflow drain 4812 of the binder purge bin 4302. The overflow tank 4813, when included, is fluidly coupled to the binder reservoir 4802 and the waste reservoir 4814. In embodiments, the overflow tank 4813 is coupled to the binder reservoir 4802 and the waste reservoir 4814 through a valve 4815, although other pathways are contemplated. Valve 4815 can be, for example, a pinch valve, a three-way valve, or a four-way valve, although other types of valves are contemplated. It is further contemplated that the overflow tank 4813 can be fluidly coupled to another part of the main circulation path instead of being fluidly coupled to the binder reservoir 4802.
In embodiments including the overflow tank 4813, binder material overflowing from the binder purge bin 4302 flows through the overflow drain 4812 into the overflow tank 4813. Binder material in the overflow tank 4813 is evaluated and, if verified that the binder material in the overflow tank 4813 is still usable, the binder material is returned to the binder reservoir 4802. If, however, the binder material in the overflow tank 4813 is not still suitable for use (e.g., it contains too many contaminants or does not otherwise meet specifications for use), the binder material is sent to the waste reservoir 4814. In embodiments including the valve 4815, the valve 4815 can be controlled by a computing device, such as control system 5000 that is configured to verify the suitability of the binder material for use and send a signal to the valve 4815 to direct the binder material to the binder reservoir 4802 or the waste reservoir 4814.
Turning now to the cleaning fluid pathway depicted in
In embodiments, the cleaning fluid is provided from the cleaning fluid reservoir 4816 through a filter 818 to a pump 4820, which in turn delivers the cleaning fluid to the cleaning station vessel 4314 through a cleaning fluid inlet 4822. As shown in
As the cleaning fluid is pumped into the cleaning station vessel 4314, the volume of the cleaning fluid accumulates to a fluid level 4600 within the cleaning station vessel 4314. The volume of cleaning fluid is used to supply cleaning fluid to the wet wipe member 4310 and the capping section 4308, as described hereinabove, and to supply cleaning fluid to the dry wipe cleaner section 4306 for cleaning the dry wipe member 4312 between uses. In embodiments, the cleaning fluid inlet 4822 can be left open to simply fill the cleaning station vessel 4314. Alternatively, the cleaning fluid inlet 4822 can be connected to the cleaning fluid inlets 4416 of the wet wipe member 4310 which then fills the fluid ports 4407 and then fills the area between the wiper blades 4406. In this setup, cleaning fluid is constantly fed when the machine is in operation and is then overflowed into the cleaning station vessel 4314.
The cleaning station vessel 4314 includes a drain 4824 that is in fluid communication with the cleaning fluid reservoir 4816. The drain 4824, which is also depicted in
In the embodiment shown in
In various embodiments, the cleaning station vessel 4314 further includes a level sensor 4828. The level sensor 4828 is used to maintain a constant height of cleaning fluid within the cleaning station vessel 4314. For example, the level sensor 4828 can determine that the fluid level 4600 of the cleaning fluid is low and, responsive to the determination, additional cleaning fluid can be pumped into the cleaning station vessel 4314 using the pump 4820. The level sensor may be any suitable type of sensor. In some embodiments, the level sensor comprises a sensor that it is able to withstand submersion within the cleaning fluid. In other embodiments, the level sensor is not disposed within the cleaning fluid, and can detect the fluid level via other means. For example, a laser level sensor may be used. In embodiments, the level sensor 4828 may be coupled to a control system 5000 which receives signals from the level sensor 4828 and provides signals to other system components, such as the pump 4820 and/or the activate drain 4826, as will be described in greater detail below. Additionally or alternatively, the level sensor 4828 may include the fluid level sensors 4322 positioned within the overflow vessel 4318, as described in accordance with
In various embodiments, one or more additional components (not shown in
As another example, in embodiments a three-way or four-way valve may be positioned within the drain 4824 and the cleaning fluid reservoir 4816 to redirect a predetermined amount of the cleaning fluid to the waste reservoir 4814. Accordingly, in embodiments, the three-way or four-way valve may replace or replicate the functionality of the active drain 4826. Moreover, it is contemplated that one or more on/off valves (e.g., pinch valves) may be used in place of or in addition to the three- or four-way valves described herein.
In embodiments, one or more of the pumps described herein, including but not limited to pump 4808 and pump 4820, are capable of moving ferrous metals as well as other types of metals. Moreover, in embodiments, one or more of the pumps described herein may include a tunable flow rate, such as through flow regulators, which enable the flow rate to be tuned, such as to enable cleaning fluid to be provided to the wet wipe member at a first flow rate and to the inlet of the cleaning station vessel at a second flow rate.
Having described a fluid management system 4800 for use in providing binder material and cleaning fluid to various components of the additive manufacturing apparatus 100, and specifically, the cleaning station 110, the binder material and cleaning fluid will now be described in detail.
In various embodiments, the binder material is a reversible binder. As defined herein, a “reversible binder” is intended to denote a thermoplastic or thermoset polymer that, during decomposition, is broken down into oligomers and other molecules that are similar or identical to the monomers used to derive the polymer. The reversible binder may be polymerized via radical chain reactions to bond particles and layers of a powder used to print the article. While many of the embodiments described below are directed to metal powder, it is contemplated that other non-metal powders are suitable, for example, for sand, ceramic, and polymer binder jetting.
Although reference is made to a “metal powder” in various embodiments herein, it is contemplated that the material used to print the article may vary depending on the type of the article and the end use of the article. In embodiments in which a metal powder is employed, the metal powder may include nickel alloys, cobalt alloys, cobalt-chromium alloys, cast alloys, titanium alloys, aluminum-based materials, tungsten, steel, stainless steel, or any other suitable material and combinations thereof.
Following deposition of a layer of the metal powder, the binder material is selectively deposited into the layer of metal powder in a pattern representative of the structure of the article being printed. According to various embodiments, the binder material may include polymers derived from unsaturated monomers. For example, the binder material may include one or more polymers having the following formulas: (CH2CHR)n, where R=—H, —OH, phenyl, alkyl, aryl. The binder material may also include one or more monofunctional acrylic polymers having the formula (CH2—CR2COOR1)n, where R1 is an alkyl or aryl, and R2 is H or CH3; di-acrylic polymers having the formula [(CH2—CR2COO)2—R3]n, where R2 is H or CH3 and R3 is a divalent hydrocarbon radical; tri-acrylic polymers having the following formula [(CH2CR1COO)3—R4]n, where R1 is H or CH3 and R4 is a trivalent hydrocarbon radical and/or poly(alkylene carbonates) including co-polymeric alkylene carbonates, such as poly(ethylene-cyclohexene carbonate) and those having the following formulas:
By way of example and not limitation, the binder material may include poly (methylmethacrylate) (PMMA), polystyrene (PS), poly (vinyl alcohol) (PVA), polyacrylic acid (PAA), Poly vinyl pyrrolidone (PVP), poly (alkylene carbonates), and polymers derived from hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), and diethylene glycol diacrylate (DGD), derivatives of any of the above, or combinations of the above.
In some embodiments described herein, the binder material further includes one or more fluorescent dyes. The inclusion of the fluorescent dyes enables an otherwise clear binder material (e.g., a binder material including PVA and water) to be detectable under certain lighting conditions, as will be described in greater detail below. In specific embodiments, the fluorescent dyes/pigments should be photochromic dyes that respond to specific light intensities, for example near IR or UV (including UVA, UVB, or UVC) light. In embodiments including the fluorescent dye, the intensity of the fluorescence is a function of the concentration of the fluorescent dye. Accordingly, the inclusion of a fluorescent dye can provide information regarding where the binder material has been deposited, how much binder material has been deposited, and/or the extent to which the binder material has cured. Moreover, the fluorescence of the binder material can enable detection of leaks or spills, fluid management applications, such as monitoring tank levels, binder material concentration, and contamination, and part detection. Specific embodiments of using the fluorescent dye in process control are provided below.
In various embodiments, the fluorescent dye in the binder material may be any suitable fluorescent dye that is compatible with the binder material. In some embodiments, the fluorescent dye is not quenched by the metal powder. Moreover, the fluorescent dye should not negatively impact the material properties of the green body, brown body, or final part. Examples of fluorescent binders are fluorescent inorganic pigments and solid solutions of fluorescent dyes in transparent synthetic resins, polymer encapsulated fluorescent dyes.
Fluorescent pigments are solid solutions of fluorescent dyes. These fluorescent dyes may include polyenes, rhodamines, coumarins, naphthalimides, fluoresceins, diazonium salt, acridines, benzoxanthenes, or combinations thereof. The fluorescent color achieved can be from a combination of a single fluorescent dye embedded in a medium (e.g., polymer or resin carrier) or by combining multiple fluorescent dyes at different ratio. When incorporated in a resin dispersion, it is contemplated that the dispersion may be water or solvent based. The dyes may be proteins or non-proteins, and may be organic or synthetic. It is contemplated that the particular dye selected will vary based on the particular embodiment employed. Examples of suitable fluorescent dyes are described in PCT Publication WO 03/029340, which is incorporated by reference herein in its entirety.
Various sizes are contemplated for the fluorescent pigment. For example, the fluorescent pigment or fluorescent dye resin may have a typical average particle size from about 0.01 to about 1 μm. The amount of fluorescent pigment or fluorescent dye resin may be in the typical range of 0.01 to 5% by weight, or from 0.1 to 2% by weight.
The binder material may further include one or more additives that facilitate deposition of the binder material into the layer of metal powder. For example, the binder material may include one or more additives such as viscosity modifiers, dispersants, stabilizers, surfactants (e.g., surface active agents) or any other suitable additive that may facilitate the jettability of the binder material and deposition of the binder material into the layer of metal powder. The surfactants may be ionic (e.g., zwitterionic, cationic, or anionic) or non-ionic, depending on the properties of the binder material and/or the metal powder.
In some embodiments, the additive(s) may improve the wettability of the metal powder to facilitate coating the metal powder with the binder material. The additive(s) may also modify the surface tension of the binder material to facilitate jettability of the binder material. For example, in embodiments, the binder material is considered jettable if the Ohnesorge number (e.g., the ratio of viscous forces to inertial and surface tension forces) is between approximately 0.01 and approximately 2.
In embodiments, the additive(s) may also include a solvent that dissolves the binder material. The solvent may be aqueous or non-aqueous, depending on the particular polymers selected and other additives that may be in the binder material. The solvent is generally non-reactive (e.g., inert) such that it does not react with the metal powder, the polymers in the binder material, or any other additives that may be in the binder material. Additionally, the solvent should readily evaporate after selective deposition of the binder material into the layer of metal powder to facilitate bonding of the binder-coated particles and the printed layers. Example solvents that may be used in the binder material include, but are not limited to, water, methylene chloride (CH2Cl2), chloroform (CHCl3), toluene, xylenes, mesitylene, anisole, 2-methoxy ethanol, Butanol, diethylene glycol, tetrahydrofuran (THF), methyl ethyl ketone (MEK), trichloroethylene (TCE), or any other suitable solvent.
The binder material may include the reversible binder, one or more monomers used to derive the reversible binder, or both. For example, in some embodiments, the reversible binder is polymerized before selective deposition into the layer of metal powder. Accordingly, in such embodiments, the binder material may include the reversible binder as a pre-formed, dissolved polymer. The reversible binder may be solubilized in a suitable solvent to facilitate jettability and deposition into the layer of the metal powder. Following deposition, the solvent may evaporate and the reversible binder may coalesce and bond the binder-coated particles and the printed layers to form the green body part.
In other embodiments, the reversible binder is polymerized after depositing the binder solution into the layer of metal powder. That is, the reversible binder may be polymerized in situ. For such embodiments, the binder material may include one or more polymerizable monomers (e.g., reactive monomers) that react to form the reversible binder. In one particular embodiment, the binder material includes the one or more polymerizable monomers and a suitable solvent. In other embodiments, the binder material does not include a solvent. Rather, the binder material may be a neat liquid of the one or more polymerizable monomers. Once the binder solution is deposited onto the layer of metal powder, the one or more polymerizable monomers may be polymerized to form the reversible binder within the layer of metal powder to form the printed layer of the green body part. In certain embodiments, the binder material may include initiators such as, for example, azobis (isobutyronitrile) (AIBN), to facilitate in situ polymerization of the one or more polymerizable monomers in the layer of metal powder.
By way of non-limiting example, in some embodiments, the binder material may include between about 0.5 weight percent (wt. %) and about 30 wt. % of the polymerized reversible binder or the polymerizable monomers used to derive the reversible binder in situ. In one embodiment, the binder material include from about 3 wt. % to about 7 wt. % of the polymer or polymerizable monomers. Additionally, the binder material may include suitable viscosity modifiers to enable a viscosity of the binder material that is from about 2 centipoise (cP) and about 200 cP. For example, depending on the viscosity of the mixture of the solvent and polymer/polymerizable monomer solution or the neat polymerizable monomer solution, the binder material may have from about 0.1 wt. % to about 15 wt. % of a viscosity modifier, such that the viscosity of the binder material is within the desired range for efficient and effective jettability.
Following deposition of the metal powder and printing of the binder material, the reversible binder is cured to form a layer of the green body part. While a portion of the solvent in the binder material may be evaporated during deposition (e.g., printing) of the binder material, a certain amount of the solvent may remain within the layer of metal powder. Therefore, in certain embodiments, the green body part may be thermally cured at a temperature that is suitable for evaporating the solvent remaining in the printed layer and allowing efficient bonding of the printed layers of the green body part.
In embodiments, the green body part may be cured to allow polymerization of the polymerizable monomers in the binder material to yield the reversible binder. For example, as discussed above, the reversible binder may be polymerized in situ after printing the binder material into the layer of metal powder. Following deposition of the binder material, the one or more polymerizable monomers in the binder material may be cured to polymerize the one or more monomers and form the printed layer of the green body part. For example, the printed layers may be exposed to heat, moisture, light, or any other suitable curing method that polymerizes the one or more polymerizable monomers in the binder material before the next layer of metal powder is deposited on top of the printed layer. In certain embodiments, the binder material may include a radical initiator (e.g., AIBN) to facilitate polymerization of the one or more polymerizable monomers. In one embodiment, the one or more polymerizable selectively deposited may be cured immediately after forming the printed layer. In other embodiments, the one or more polymerizable monomers may be cured after a desired number of printed layers has been formed. Excess metal powder (e.g., the metal powder that is not bonded by the reversible binder) may be removed after curing to prepare the green body for post-printing processing. After curing, the green body may undergo a drying step to remove any solvent and/or other volatile materials that remain in the green body part. For example, the green body may be dried in a vacuum, under an inert atmosphere (e.g., nitrogen or argon), or air.
Additional details on binder materials suitable for use in the embodiments described herein may be found in U.S. Patent Application Publication No. 2018/00714820 to Natarajan et al., entitled “Reversible binders for use in binder jetting additive manufacturing techniques” and filed on Sep. 9, 2016, the entire contents of which is hereby incorporated by reference. Moreover, it is contemplated that other binder materials may be used with the cleaning station and/or additive manufacturing apparatus described herein, depending on the particular embodiment.
In various embodiments, the cleaning fluid is compatible with the binder material (e.g., capable of dissolving or otherwise enabling with binder material to be wiped away) and is safe for the components of the additive manufacturing apparatus 100 (e.g., does not cause rust the need for excessive maintenance or cleaning). In some embodiments, such as embodiments in which the binder material is water-based, the cleaning fluid is a water-miscible cleaning fluid.
In various embodiments, the cleaning fluid includes from 0.1 wt. % to 20 wt. % of a cleaning agent. For example, the cleaning fluid can include from 0.5 wt. % to 10 wt. %, from 1 wt. % to 10 wt. %, or from 1 wt. % to 5 wt. % of the cleaning agent. In embodiments, the cleaning agent is an organic solvent. Suitable organic solvents for use in the cleaning fluid include dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), methylpyrrolidone (NMP), N—N-dimethylacetamide (DMAc), 1,3-dimethyl-2-imidazolidnone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), ethylene glycol, diethyl glycol, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, propylene glycol, and mixtures thereof. In particular embodiments, the cleaning agent is DMF, NMP, DMSO, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, ethylene glycol, or combinations thereof.
It is contemplated that in some embodiments, the cleaning fluid may include one or more additives, although in other embodiments, the cleaning fluid includes the cleaning agent and water. Accordingly, in various embodiments, the cleaning fluid includes from 80 wt. % to 99.9 wt. % water, from 90 wt. % to 99.5 wt. % water, from 90 wt. % to 99 wt. % water, or from 95 wt. % to 99 wt. % water.
The cleaning fluid of various embodiments has a viscosity that enables the cleaning fluid to flow through the cleaning fluid pathway without issue. In embodiments, the cleaning fluid has a viscosity of less than 10 cP or less than 5 cP at 25° C. For example, the cleaning fluid may have a viscosity of from 0.5 cP to 5 cP, 0.5 cP to 3 cP, from 1 cP to 2 cP, or from 1 cP to 1.5 cP.
Additionally, or alternatively, the cleaning fluid of various embodiments has a boiling point that is greater than or equal to the boiling point of water. By having a boiling point that is greater than or equal to that of water, the cleaning fluid can resist evaporation and keep the print head 150 moist by preventing the binder material from drying. In various embodiments, the cleaning fluid has a boiling point that is greater than or equal to 100° C. at 1 atm, greater than or equal to 110° C. at 1 atm, greater than or equal to 125° C. at 1 atm, or even greater than or equal to 150° C. at 1 atm.
In embodiments, the cleaning fluid is formulated such that the density of the cleaning fluid is close to the density of water (e.g., 1 g/cm3). In such embodiments, contaminants within the cleaning fluid, such as binder material and other debris, can be detected based on a change in density of the cleaning fluid, as will be described in greater detail below. Accordingly, in various embodiments, the cleaning fluid has a density of from 0.900 g/cm3 to 1.400 g/cm3 from 0.900 g/cm3 to 1.200 g/cm3 or from 0.900 g/cm3 to 1.100 g/cm3. For example, the cleaning fluid may have a density of from 0.905 g/cm3 to 1.195 g/cm3, from 0.910 g/cm3 to 1.175 g/cm3, from 0.950 g/cm3 to 1.150 g/cm3, from 0.905 g/cm3 to 1.095 g/cm3, from 0.910 g/cm3 to 1.075 g/cm3, or from 0.950 g/cm3 to 1.050 g/cm3.
The cleaning fluid may be heated, such as by a heater positioned along the cleaning fluid pathway, although in other embodiments, the cleaning fluid may be applied to the print head 150 at approximately ambient temperature. As used herein, “ambient temperature” within the machine may differ from room temperature outside the machine. For example, the temperature of the machine may be elevated. In other embodiments, the cleaning fluid may be cooled to a temperature below ambient temperature before application to the print head 150. For example, the cleaning fluid may be cooled to a temperature sufficient to cool the print head. Cooling of the cleaning fluid may be accomplished using a cooling apparatus, or simply by recirculation of the cleaning fluid through the cleaning fluid pathway.
As described herein, the cleaning fluid can be applied to the print head 150 to dissolve precipitant (e.g., resulting from partial evaporation of binder material) and other debris deposited on the print head 150 and within the nozzles of the print head 150. Because the cleaning fluid is recirculated through the system and is also specially formulated to be compatible with the cleaning station 110, the print head 150, and the binder material ejected from the print head 150, in various embodiments, the cleaning fluid is monitored to determine when the cleaning fluid should be reconditioned or replaced. An example method 4900 of monitoring a status of the cleaning fluid is described in
In the method depicted in
Next, the cleaning fluid is circulated through the cleaning fluid pathway for a predetermined amount of time (block 4904). In embodiments, circulation of the cleaning fluid through the cleaning fluid pathway includes using the cleaning fluid to clean the print head 150. The predetermined period of time can vary depending on the particular embodiment. For example, the “predetermined time” may be the sampling rate of an instrument, which would ostensibly yield an effective “continuous” monitoring system. In other embodiments, the predetermined period of time can be a period of 1 minute, 5 minutes, 10 minutes, 30 minutes, an hour, 2 hours, or the like. After the passage of the predetermined period of time, a subsequent value corresponding to the physical property of the cleaning fluid is obtained (block 4906). The subsequent value can be determined in the same way as the initial value was determined, or by a different method. For example, a user may input the initial value for a cleaning fluid when the cleaning fluid is introduced to the system, but a sensor may be used to obtain subsequent values corresponding to the physical property.
Next, an amount of contaminant in the cleaning fluid is estimated based on the initial value and the subsequent value corresponding to the physical property of the cleaning fluid (block 4908). For example, the initial and subsequent values may be stored in a look up table (LUT) stored in the memory of the control system 5000 along with an estimated contaminant amount. Alternatively, the control system 5000 may perform one or more calculations to determine the amount of contaminant in the cleaning fluid. The contaminant may include, for example, dissolved, mixed and/or suspended binder material removed from the print head 150, dissolved, mixed and/or suspended build material (e.g., metal powder), or the like. As used herein, “contaminant” includes, but is not limited to, precipitant deposited on the print head. In embodiments, the contaminant comprises polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid (PVA), or derivatives thereof. In embodiments, as an alternative to or in addition to determining an estimated contaminant amount, an amount of evaporation is estimated. For example, the initial and subsequent values may be stored in a look up table (LUT) stored in the memory of the control system 5000 along with an estimated evaporation amount. Based on the amount of contaminant in the cleaning fluid, the amount of evaporation of the cleaning fluid, or both, a cleaning fluid maintenance process is selected from a plurality of available maintenance processes (block 4910). In some embodiments, available maintenance processes may include adding water (or another solvent) to the cleaning fluid, replacing a portion of the cleaning fluid containing contaminants with fresh cleaning fluid, replacing a majority of the volume of the cleaning fluid with fresh cleaning fluid, or returning the cleaning fluid containing the contaminants to the cleaning fluid reservoir. Finally, the selected cleaning fluid maintenance process is performed (block 4912).
By way of illustration, the process may include using a density meter to automatically determine an initial density of the cleaning fluid. Then, after the cleaning fluid has been used for a period of about 15 minutes, the density meter again measures the density of the cleaning fluid. Various time periods are considered suitable and can be tailored based on print cycles, cleaning cycles, and the like. In one or more embodiments, the density of the cleaning fluid may be measured as frequently as every 30 seconds or after 15 minutes, or in a further embodiment, density may be measured every 30-60 seconds. The density meter transmits both the initial density and the subsequent density of the cleaning fluid to the control system 5000, which then estimates an amount of contaminant in the cleaning fluid based on the change in density. When the estimated amount of contaminant is within a suitable range, the cleaning fluid recirculated through the cleaning fluid pathway. When the estimated amount of contaminant is moderate, water may be added to the cleaning fluid, or a portion of the cleaning fluid may be diverted to the waste reservoir by activating a three-way valve (described above) while new cleaning fluid is added to the cleaning fluid reservoir. Alternatively, when the estimated amount of contaminant is high, the entire volume of the cleaning fluid is diverted to the waste reservoir and fresh cleaning fluid is added to the cleaning fluid reservoir.
As another example, the process may include using a camera to detect an initial fluorescence of the cleaning fluid. Then, after the cleaning fluid has been used for a period of about an hour, the camera again measures the fluorescence of the cleaning fluid. In embodiments in which the binder material includes a fluorescent dye, an increase in the fluorescence of the cleaning fluid can indicate the presence of binder material in the cleaning fluid. The camera transmits both the initial fluorescence and the subsequent fluorescence of the cleaning fluid to the control system 5000, which then estimates an amount of contaminant in the cleaning fluid based on the change in fluorescence. When the estimated amount of contaminant is within a suitable range, the cleaning fluid recirculated through the cleaning fluid pathway. When the estimated amount of contaminant is moderate, water may be added to the cleaning fluid, or a portion of the cleaning fluid may be diverted to the waste reservoir by activating a three-way valve (described above) while new cleaning fluid is added to the cleaning fluid reservoir. Alternatively, when the estimated amount of contaminant is high, the entire volume of the cleaning fluid is diverted to the waste reservoir and fresh cleaning fluid is added to the cleaning fluid reservoir.
Although various embodiments are described herein with reference to measurement of a single physical property of the cleaning fluid, it is contemplated that in other embodiments, more than one physical property can be monitored and used to determine a cleaning fluid maintenance process to be performed. For example, both density and viscosity can be used to select a cleaning fluid maintenance process. By way of example, the control system 5000 may select a maintenance process that includes adding water to the cleaning fluid based on a change in the density of the cleaning fluid, but the control system 5000 may instead select a maintenance process that includes partial replacement of the cleaning fluid or replacement of the majority of the volume of the cleaning fluid when the density has decreased too much, indicating that the cleaning fluid may be becoming too diluted to function properly. In embodiments, the selection of the cleaning fluid maintenance process can be based on the viscosity, the surface tension, or both, of the cleaning fluid.
Referring now to
In embodiments, the control system 5000 may be configured to receive signals from one or more sensors of the fluid management system and, based on these signals, actuate one or more of the print head 150, the pump 4808, the pump 4820, the activate drain 4826, or other valves, pumps, and drains that may be included in the fluid management system. In some embodiments, the control system 5000 may be configured to receive signals from one or more additional sensors in the additive manufacturing apparatus 100 and, based on these signals, actuate one or more of the actuators 4602a, 4602b coupled to the wet wipe member 4310 and the dry wipe member 4312, and the actuator 4706 coupled to the sponge support 4704 or cap 4710 to raise and/or lower the components of the cleaning station 110 for use.
In various embodiments, the control system 5000 is configured to receive signals from and send signals to one or more components described herein. Accordingly, the control system 5000, in embodiments, can enable one or more of the functions described herein, including, without limitation, movement of any or all of the components of the cleaning station (e.g., the wet wipe member, the dry wipe member, the capping section, and the cleaning station vessel), adjustment of one more components described herein, monitoring the status of binder material and/or cleaning fluid described herein, monitoring performance of the additive manufacturing apparatus or any component thereof, measurements of various components, opening and closing of ports and valves, and the like. In embodiments, the control system 5000 is configured to control motion of the recoat head, the print head, and other components of the additive manufacturing device described herein.
Moreover, it is contemplated that, although control system 5000 is shown in
In the embodiments described herein, the computer readable and executable instructions for controlling the additive manufacturing apparatus 100, and particularly, the cleaning station 110 and the fluid management system, are stored in the memory 5004 of the control system 5000. The memory 5004 is a non-transitory computer readable memory. The memory 5004 may be configured as, for example and without limitation, volatile and/or nonvolatile memory and, as such, may include random access memory (including SRAM, DRAM, and/or other types of random access memory), flash memory, registers, compact discs (CD), digital versatile discs (DVD), and/or other types of storage components.
Various methods have been described herein that may be executed by the control system 5000. For example, the monitoring of the status of the cleaning fluid and the selection and implementation of a cleaning fluid maintenance process, the actuation of the wet wipe member, the dry wipe member, and the sponge, and the ejection of binder material from the print head may each be performed through execution of computer readable and executable instructions stored in the memory 5004 by the processor 5002. It is contemplated that one or more of these functions may alternatively be performed by one or more additional computing devices, which may be communicatively coupled to the control system 5000. For example, the monitoring of the status of the cleaning fluid and the selection and implementation of a cleaning fluid maintenance process may be performed from a computing device that is separate from, but communicatively coupled to, the control system 5000. It is also contemplated that additional functions may be performed by the control system 5000 and/or additional computing devices communicatively coupled thereto.
For example, in some embodiments in which the binder material includes a fluorescent dye, as described above, the control system 5000 (or other computing device communicatively coupled thereto) may determine an amount of cure of the printed part (e.g., through storage and execution of computer readable and executable instructions). A UV camera, a visible or other detection system can be used to detect the fluorescence of the binder.
During the operation of an additive manufacturing apparatus, it may be difficult to assess the quantity, geometric fidelity, and extent of cure of binder deposited into the powder bed. Powder soaked with binder often provides poor visual contrast for reliable optical observation of each layer or multiple layers of the green body part. However, the present embodiments address this problem by including in the binder composition one or more fluorescent photochromic dyes. After layerwise jetting deposition into the powder and any subsequent thermal treatment, the subsequent exposure of the binder-powder surface to UV or other electromagnetic radiation will cause the fluorescent dyes to emit light.
Based on the emitted light, a control system including a UV camera can be used to image each layer of the 3D print. Using the control system, the acquired image(s) at specified time(s) can be compared to the expected quantity of binder jetted and identify spatial defects including binder jet print head misfires, inaccurate binder quantity deposition (saturation), as well as insufficient binder cure.
In one embodiment, the control system can determine the presence of binder solvent increases the quantum yield of emitted light as compared to a solvent free sample. If there is solvent in the binder-powder layer, the control system can pinpoint locations where solvent has not been effectively removed. Improper solvent removal may thus indicate areas of incomplete curing. Alternatively, the control system may detect areas of low binder based on the emitted light. This could indicate the clogging of the print head.
After detecting these defects, the control system enables the operator of the apparatus to troubleshoot or perform diagnostic checks on the additive manufacturing device, for example, by checking the recoat head and/or print head for clogging issues. In one embodiment, the detection of a defect may trigger a pattern test to determine if one or more print head nozzles are clogged.
In one embodiment for monitoring the performance of an additive manufacturing device using a fluorescent binder, the method comprise exposing at least one layer comprising the fluorescent binder to electromagnetic radiation. The fluorescent binder includes fluorescent material which emits light in response to the electromagnetic radiation. Next, the method includes recording the emitted light intensity of the at least one layer after exposure, and computing a level of binder, solvent, or both within the layer by utilizing a control system which correlates the recorded emitted light intensity to the level of binder, solvent, or both in the layer versus time. Defects may be located in the layer when the recorded emitted light intensity deviates from expected emitted light intensity values, or when the level of binder, solvent or both deviates from expected levels.
Further aspects of the invention are provided by the subject matter of the following clauses:
1. A method for forming an object, the method comprising: moving a recoat assembly in a coating direction over a build material, wherein the recoat assembly comprises a first roller and a second roller that is spaced apart from the first roller; rotating the first roller of the recoat assembly in a counter-rotation direction, such that a bottom of the first roller moves in the coating direction; contacting the build material with the first roller of the recoat assembly, thereby fluidizing at least a portion of the build material; irradiating, with a front energy source coupled to a front end of the recoat assembly, an initial layer of build material positioned in a build area; subsequent to irradiating the initial layer of build material, spreading the build material on the build area with the first roller, thereby depositing a second layer of the build material over the initial layer of build material; and subsequent to spreading the second layer of the build material, irradiating, with a rear energy source positioned rearward of the front energy source, the second layer of build material within the build area.
2. The method of any preceding clause, wherein the second roller is positioned above the first roller in a vertical direction, such that the second roller does not contact the build material.
3. The method of any preceding clause, wherein the first roller is a front roller and the second roller is a rear roller positioned rearward of the first roller.
4. The method of any preceding clause, further comprising: rotating the rear roller in a rotation direction that is the opposite of the counter-rotation direction; and contacting the second layer of the build material within the build area with the rear roller.
5. The method of any preceding clause, wherein rotating the rear roller in the rotation direction comprises rotating the rear roller at a rotational velocity that corresponds to a linear velocity of the recoat assembly.
6. The method of any preceding clause, further comprising, subsequent to at least one of irradiating the initial layer of build material with the front energy source and irradiating the second layer of build material with the rear energy source, detecting a temperature of the irradiated build material with a temperature sensor.
7. The method of any preceding clause, further comprising changing at least one parameter of the front energy source or the rear energy source based at least in part on the detected temperature.
8. The method of any preceding clause, wherein at least one of irradiating the initial layer of build material with the front energy source and irradiating the second layer of build material with the rear energy source comprises applying a predetermined power to the front energy source or the rear energy source, the method further comprising changing the predetermined power based at least in part on the detected temperature.
9. A method for forming an object of any preceding clause, the method comprising: moving a recoat assembly over a build material, wherein the recoat assembly comprises a first roller and a second roller that is spaced apart from the first roller; moving the second roller above the first roller in a vertical direction; rotating the first roller of the recoat assembly in a counter-rotation direction, such that a bottom of the first roller moves in a coating direction; contacting the build material with the first roller of the recoat assembly, thereby fluidizing at least a portion of the build material, while the second roller is spaced apart from the build material in the vertical direction; and moving the fluidized build material with the first roller, thereby depositing a second layer of the build material over an initial layer of build material positioned in a build area.
10. The method of any preceding clause, further comprising, subsequent to depositing the second layer of build material, moving the first roller upward in the vertical direction such that the first roller is spaced apart from the second layer of build material and moving the recoat assembly to a home position in a direction that is the opposite of the coating direction.
11. The method of any preceding clause, wherein moving the recoat assembly to the home position comprises moving the recoat assembly at a return speed, and wherein moving the fluidized build material comprises moving the recoat assembly in the coating direction at a coating speed, wherein the return speed is greater than the coating speed.
12. The method of any preceding clause, further comprising, prior to moving the recoat assembly to the home position, lowering the second roller such that the second roller contacts the second layer of build material.
13. The method of any preceding clause, further comprising rotating the second roller in the counter-rotation direction.
14. The method of any preceding clause, wherein rotating the second roller in the counter-rotation direction comprises rotating the second roller at a rotational velocity that corresponds to a linear velocity of the recoat assembly moving to the home position.
15. The method of any preceding clause, wherein the second roller comprises a second roller diameter and the first roller comprises a first roller diameter, wherein the second roller diameter is greater than the first roller diameter.
16. The method of any preceding clause, further comprising irradiating, with a front energy source coupled to a front end of the recoat assembly, the initial layer of build material positioned in the build area.
17. The method of any preceding clause, further comprising subsequent to moving the second layer of the build material, irradiating, with a rear energy source coupled to the recoat assembly, the second layer of build material within the build area.
18. A recoat assembly for an additive manufacturing system of any preceding clause, the recoat assembly comprising: a base member; a front roller rotatably coupled to the base member; a rear roller rotatably coupled to the base member, wherein the front roller is spaced apart from the rear roller; a front energy source coupled to the base member and positioned forward of the front roller, wherein the front energy source emits energy forward of the front roller; and a rear energy source coupled to the base member and positioned rearward of the front energy source, wherein the rear energy source emits energy rearward of the front energy source.
19. The recoat assembly of any preceding clause, further comprising a vertical actuator coupled to at least one of the front roller and the rear roller, and the base member, wherein the vertical actuator moves the at least one of the front roller and the rear roller in a vertical direction with respect to the base member.
20. The recoat assembly of any preceding clause, further comprising a hard stop that restricts movement of the at least one of the front roller and the rear roller in a vertical direction.
21. The recoat assembly of any preceding clause, further comprising a dust shield that at least partially encapsulates the hard stop.
22. The recoat assembly of any preceding clause, further comprising a vertical actuator coupled to the front roller and the rear roller such that the front roller and the rear roller are movable with respect to the base member independently of one another.
23. The recoat assembly of any preceding clause, wherein the vertical actuator is a first vertical actuator coupled to the front roller, and the recoat assembly further comprises a second vertical actuator coupled to the rear roller, wherein the second vertical actuator moves the rear roller in a vertical direction with respect to the base member.
24. The recoat assembly of any preceding clause, wherein the front roller has a front roller diameter and the rear roller has a rear roller diameter, wherein the front roller diameter and the rear roller diameter are different.
25. The recoat assembly of any preceding clause, further comprising a powder engaging member coupled to the base member and positioned forward of the front roller at a height that is within a roller window defined by the front roller.
26. A recoat assembly for an additive manufacturing system of any preceding clause, the recoat assembly comprising: a base member; a first roller rotatably coupled to the base member, the first roller having a first roller diameter; and a second roller rotatably coupled to the base member, wherein the second roller is spaced apart from the first roller and has a second roller diameter, wherein the second roller diameter is greater than the first roller diameter.
27. The recoat assembly of any preceding clause, wherein the first roller is a front roller and the second roller is a rear roller, wherein the front roller is positioned forward of the rear roller.
28. The recoat assembly of any preceding clause, further comprising a front energy source coupled to the base member and positioned forward of the front roller, wherein the front energy source emits energy forward of the front roller; and a rear energy source coupled to the base member and positioned rearward of the front energy source.
29. The recoat assembly of any preceding clause, further comprising a powder engaging member coupled to the base member and positioned forward of the front roller at a height that is within a roller window defined by the front roller.
30. The recoat assembly of any preceding clause, further comprising a cleaning member engaged with at least one of the first roller and the second roller.
31. A recoat assembly for an additive manufacturing system any preceding clause, the recoat assembly comprising: a base member that is movable in a lateral direction; a powder spreading member coupled to the base member, wherein the base member at least partially encapsulates the powder spreading member; and a vacuum in fluid communication with at least a portion of the base member.
32. The recoat assembly of any preceding clause, further comprising an agitation device configured to vibrate the recoat assembly.
33. The recoat assembly of any preceding clause, wherein the base member comprises a primary containment housing that at least partially encapsulates the powder spreading member and a secondary containment housing that at least partially encapsulates and is spaced apart from the primary containment housing.
34. The recoat assembly of any preceding clause, wherein the vacuum is in fluid communication with a cavity defined by the primary containment housing and the secondary containment housing.
35. The recoat assembly of any preceding clause, wherein the powder spreading member is a doctor blade.
36. The recoat assembly of any preceding clause, wherein the powder spreading member is a roller rotatably coupled to the base member.
37. The recoat assembly of any preceding clause, wherein the roller is a first roller, and the recoat assembly further comprises a second roller rotatably coupled to the base member and at least partially encapsulated by the base member.
38. The recoat assembly of any preceding clause, wherein the recoat assembly further comprises a cleaning member selectively engagable with at least one of the first roller and the second roller.
39. The recoat assembly of any preceding clause, wherein the base member comprises a primary containment housing that at least partially encapsulates the powder spreading member.
40. A method for forming an object of any preceding clause, the method comprising: moving a recoat assembly over a build material a coating direction, wherein the recoat assembly comprises a powder spreading member; contacting the build material with the powder spreading member, causing at least a portion of the build material to become airborne; and drawing airborne build material out of the recoat assembly with a vacuum in fluid communication with the recoat assembly.
41. The method of any preceding clause, further comprising moving build material over a build area with the powder spreading member, thereby depositing a second layer of the build material over an initial layer of build material.
42. The method of any preceding clause, wherein drawing the airborne build material out of the recoat assembly comprises applying a vacuum pressure to a containment housing that at least partially encapsulates the powder spreading member.
43. The method of any preceding clause, further comprising, subsequent to moving the recoat assembly over the build material, directing process gas to the recoat assembly.
44. The method of any preceding clause, wherein drawing the airborne build material out of the recoat assembly comprises applying a vacuum pressure to a secondary containment housing that is spaced apart from and at least partially encapsulates a primary containment housing that at least partially encapsulates the powder spreading member.
45. The method of any preceding clause, further comprising, irradiating, with a front energy source coupled to an end of the recoat assembly, an initial layer of build material.
46. The method of any preceding clause, further comprising, subsequent to irradiating the initial layer of build material, moving the fluidized build material to a build area, thereby depositing a second layer of the build material over the initial layer of build material.
47. An additive manufacturing system of any preceding clause comprising: a recoat assembly comprising: a base member that is movable in a lateral direction; a powder spreading member coupled to the base member, wherein the base member at least partially encapsulates the powder spreading member; and a vacuum in fluid communication with at least a portion of the base member; an electronic control unit communicatively coupled to the vacuum; and a build area positioned below the recoat assembly.
48. The additive manufacturing system of any preceding clause, wherein the build area comprises a build receptacle positioned below the recoat assembly.
49. The additive manufacturing system of any preceding clause, further comprising a supply receptacle spaced apart from the build area.
50. The additive manufacturing system of any preceding clause, further comprising a build material hopper.
51. The additive manufacturing system of any preceding clause, wherein the electronic control unit directs the vacuum to draw build material out of the recoat assembly.
52. The additive manufacturing system of any preceding clause, wherein the base member comprises a primary containment housing that at least partially encapsulates the powder spreading member and a secondary containment housing that at least partially encapsulates and is spaced apart from the primary containment housing.
53. The additive manufacturing system of any preceding clause, further comprising a recoat assembly transverse actuator coupled to the base member and communicatively coupled to the electronic control unit.
54. The additive manufacturing system of any preceding clause, wherein the electronic control unit directs the recoat assembly transverse actuator to move the base member in the lateral direction to move build material with the powder spreading member, thereby depositing a second layer of the build material over an initial layer of build material positioned in the build area.
55. The additive manufacturing system of any preceding clause, wherein the electronic control unit directs the vacuum to draw airborne build material out of the recoat assembly while directing the recoat assembly transverse actuator to move the build material.
56. A recoat assembly for an additive manufacturing system of any preceding clause, the recoat assembly comprising: a first roller support; a second roller support; a first roller disposed between and supported by the first roller support and the second roller support; a first rotational actuator operably coupled to the first roller and configured to rotate the first roller about a first rotation axis; and a first sensor mechanically coupled to and in contact with the first roller support, wherein the first sensor outputs a first output signal indicative of a first force incident upon the first roller.
57. The recoat assembly of any preceding clause, wherein the first sensor is a strain gauge mechanically coupled to the first roller support, and wherein the strain gauge is oriented in order to measure a strain in at least one of a vertical direction transverse to the first rotation axis of the first roller or a horizontal direction transverse to the first rotation axis of the first roller.
58. The recoat assembly of any preceding clause, wherein the first sensor is a load cell mechanically coupled to the first roller support and configured to measure a force in a vertical direction transverse to the first rotation axis of the first roller.
59. The recoat assembly of any preceding clause, wherein the first roller support includes a flexure to which the first sensor is coupled.
60. The recoat assembly of any preceding clause, further comprising a second sensor mechanically coupled to and in contact with the second roller support.
61. The recoat assembly of any preceding clause, further comprising: a third roller support; a fourth roller support; a second roller disposed between and supported by the third roller support and the fourth roller support; a second rotational actuator operably coupled to the second roller and configured to rotate the second roller about a second rotation axis, the second rotation axis being parallel to the first rotation axis; and a third sensor mechanically coupled to and in contact with the third roller support, wherein the third sensor outputs a third output signal indicative of a second force incident upon the second roller.
62. The recoat assembly of any preceding clause, further comprising an accelerometer mechanically coupled to the first roller support.
63. An additive manufacturing system of any preceding clause comprising: a recoat assembly comprising: a first roller support; a second roller support; a first roller disposed between and supported by the first roller support and the second roller support; a first rotational actuator operably coupled to the first roller and configured to rotate the first roller about a first rotation axis; a first sensor mechanically coupled to and in contact with the first roller support, wherein the first sensor outputs a first output signal indicative of a first force incident upon the first roller; and an electronic control unit configured to: receive the first output signal of the first sensor; determine a first force on the first roller based on the first output signal of the first sensor; and adjust at least one operating parameter of the additive manufacturing system in response to the determined first force.
64. The additive manufacturing system of any preceding clause, further comprising: a build area; a transverse actuator operably coupled to the recoat assembly and operable to move the recoat assembly relative to the build area to spread a build material on the build area; and a current sensor configured to sense a current driving the transverse actuator, wherein the electronic control unit is configured to adjust the at least one operating parameter of the additive manufacturing system based on the sensed current.
65. The additive manufacturing system of any preceding clause, wherein the at least one parameter of the additive manufacturing system comprises a speed with which the transverse actuator moves the recoat assembly relative to the build area.
66. The additive manufacturing system of any preceding clause, further comprising: a build area; and a vertical actuator for moving the first roller in a vertical direction transverse to the rotation axis of the first roller, wherein the at least one parameter of the additive manufacturing system comprises a height of the first roller relative to the build area set by the vertical actuator.
67. The additive manufacturing system of any preceding clause, further comprising: a build area; a print head for depositing binder material; and a print head actuator operably coupled to the print head and operable to move the print head relative to the build area to deposit binder material on the build area, wherein the at least one parameter of the additive manufacturing system comprises a speed with which the print head actuator moves the print head relative to the build area.
68. A method of adjusting at least one operating parameter of an additive manufacturing system of any preceding clause, the method comprising: distributing a layer of a build material on a build area with a recoat assembly, the recoat assembly comprising a first roller disposed between and supported by a first roller support and a second roller support, a first rotational actuator operably coupled to the first roller and configured to rotate the first roller about a first rotation axis, and a first sensor mechanically coupled to and in contact with the first roller support; receiving a first output signal from the first sensor as the layer of the build material is distributed on the build platform with the recoat assembly; determining a first force on the first roller based on the first output signal of the first sensor; and adjusting the at least one operating parameter of the additive manufacturing system in response to the determined first force.
69. The method of any preceding clause, wherein the at least one operating parameter of the additive manufacturing system comprises one or more of: (i) a speed with which a transverse actuator moves the recoat assembly relative to the build area; (ii) a speed of rotation of the first rotational actuator; (iii) a target thickness of a subsequent layer of the build material; and (iv) a height of the first roller relative to the build area.
70. The method of any preceding clause, wherein: the at least one operating parameter of the additive manufacturing system is adjusted based on a comparison of an expected force on the first roller to the first force on the first roller determined based on the first output signal of the first sensor.
71. The method of any preceding clause, further comprising: determining a type of defect based on the comparison of the expected force on the first roller to the first force on the first roller determined based on the first output signal of the first sensor; and adjusting the at least one operating parameter of the additive manufacturing system based on the type of defect.
72. The method of any preceding clause, wherein adjusting the at least one operating parameter of the additive manufacturing system in response to the determined first force comprises one or more of: (i) adjusting the at least one operating parameter of the additive manufacturing system while the layer is being distributed by the recoat assembly; and (ii) adjusting the at least one operating parameter of the additive manufacturing system when a next layer is distributed by the recoat assembly.
73. The method of any preceding clause, further comprising determining a wear parameter of the first roller based on the determined first force.
74. The method of any preceding clause, wherein the recoat assembly further comprises a second sensor mechanically coupled to and in contact with the second roller support, the method further comprising: receiving a second output signal from the second sensor as the layer of the build material is distributed on the build area with the recoat assembly; and determining the first force on the first roller based on the first output signal of the first sensor and the second output signal of the second sensor.
75. The method of any preceding clause, wherein the recoat assembly further comprises a second roller disposed between a third roller support and a fourth roller support, a second rotational actuator operably coupled to the second roller and configured to rotate the second roller about a second rotation axis, and a third sensor mechanically coupled to and in contact with the third roller support, the method further comprising: receiving a third output signal from the third sensor as the layer of the build material is distributed on the build area with the recoat assembly; determining a second force on the second roller based on the third output signal of the third sensor; and adjusting the at least one operating parameter of the additive manufacturing system in response to the determined first force and the determined second force.
76. The method of any preceding clause, further comprising: sensing a current driving a transverse actuator that moves the recoat assembly relative to the build area; and adjusting the at least one operating parameter of the additive manufacturing system based on the sensed current.
77. The method of any preceding clause, further comprising: determining a roller collision event based on an output of at least one accelerometer; and adjusting the at least one operating parameter of the additive manufacturing system when the roller collision event is determined to have occurred.
78. A cleaning station for an additive manufacturing system of any preceding clause, wherein the cleaning station comprises: a cleaning station vessel comprising a wet wipe cleaner section and a dry wipe cleaner section downstream of the wet wiper section, wherein: the wet wipe cleaner section comprises a wet wipe member coupled to an actuator, the actuator being operable to vertically raise and lower the wet wipe member into the cleaning station vessel; and the dry wipe cleaner section comprises a dry wipe member coupled to an actuator, the actuator being operable to vertically raise and lower the dry wipe member into the cleaning station vessel, wherein the wet wipe cleaner section and the dry wipe cleaner section are arranged sequentially such that the wet wipe member is configured to apply cleaning fluid to a print head and the dry wipe member is configured to remove excess cleaning fluid from the print head after cleaning by the wet wipe cleaner section.
79. The cleaning station of any preceding clause, further comprising a capping section operable to maintain a print head in a wet state when the print head is idle.
80. The cleaning station of any preceding clause, wherein the capping section comprises a sponge coupled to an actuator, the actuator being operable to vertically raise and lower the sponge into the cleaning station vessel.
81. The cleaning station of any preceding clause, wherein at least a portion of the sponge extends above a fluid level of the cleaning fluid.
82. The cleaning station of any preceding clause, wherein the capping section is coupled to an actuator operable to vertically raise and lower the capping section into the cleaning station vessel.
83. The cleaning station of any preceding clause, wherein the cleaning station vessel comprises a plurality of inlet ports located within the cleaning station vessel to circulate the cleaning fluid within the cleaning station vessel and a drain located within the cleaning station vessel through which contaminants and cleaning fluid exit the cleaning station vessel.
84. The cleaning station of any preceding clause, wherein the cleaning station vessel is in fluid communication with an overflow vessel comprising a first fluid level sensor and a second fluid level sensor, wherein cleaning fluid is pumped out of the overflow vessel responsive to the first fluid level sensor and the second fluid level sensor detecting the cleaning fluid until neither of the first fluid level sensor and the second fluid level sensor detects the cleaning fluid.
85. A method of cleaning a print head used in an additive manufacturing system of any preceding clause, the additive manufacturing system comprising a cleaning station and a build platform, wherein the cleaning station comprises: a binder purge bin; and a cleaning station vessel comprising a wet wipe cleaner section, and a dry wipe cleaner section, wherein the cleaning station vessel comprises cleaning fluid, and wherein the method comprises: passing the print head over the binder purge bin to facilitate discharge of contaminants from the print head via backpressure; introducing the print head to the wet wipe cleaner section so that cleaning fluid is applied to the print head by a wet wipe member; and introducing the print head to the dry wipe cleaner section so that cleaning fluid is removed by a dry wipe member and the print head is thereby cleaned.
86. The method of any preceding clause, further comprising introducing the print head to an additional purge bin downstream of the dry wipe cleaner section and upstream of the build platform.
87. The method of any preceding clause, wherein the dry wipe member is vertically raised out of the cleaning fluid before completion of discharge of contaminants from the print head.
88. The method of any preceding clause, wherein the wet wipe member is vertically raised out of the out of the cleaning fluid when discharge of contaminants from the print head is complete.
89. The method of any preceding clause, wherein excess binder is discharged into the binder purge bin while a recoat head is operating in a direction supplying build material to a working surface of the build platform.
90. The method of any preceding clause, wherein the steps of introducing the print head to the wet wipe cleaner section and introducing the print head to the dry wipe cleaner section are performed while a recoat head is traveling in a direction from the build platform toward a recoat home position.
91. The method of any preceding clause, further comprising removing cleaning fluid from the cleaning station vessel if a fluid level of cleaning fluid exceeds a maximum fluid level.
92. The method of any preceding clause, further comprising adjusting one or more components of the cleaning station, the adjusting comprising: adjusting a vertical position of one or more of a top edge of the wet wipe member and a top edge of the dry wipe member to a position such that the one or more of the top edge of the wet wipe member and the top edge of the dry wipe member is vertically lower than a first section of a height gauge having a first vertical position and vertically higher than a second section of the height gauge having a second vertical position; wherein the height gauge is affixed to a print head assembly comprising the print head.
93. The method of any preceding clause, further comprising: prior to passing the print head over the binder purge bin, introducing the print head to at least one of the dry wipe cleaner section and the wet wipe cleaner section to pre-clean the print head.
94. The method of any preceding clause, further comprising: introducing the print head to a purge wipe member after the discharge of contaminants from the print head so that binder fluid discharged from the print head with the contaminants are wiped from a face of the print head prior to introducing the print head to the wet wipe cleaner section.
95. A method for storing a print head of any preceding clause comprising: applying cleaning fluid to the print head using a wet wipe member; removing cleaning fluid from the print head using a dry wipe member; and applying a cover to the print head to create a non-curing environment around the print head.
96. The method of any preceding clause, wherein applying the cover comprises actuating an actuator coupled to a wet sponge to raise the wet sponge within a cleaning station vessel into contact with the print head.
97. The method of any preceding clause, wherein applying the cover comprises bringing the print head into contact with a cleaning vessel containing the cleaning fluid to maintain a humidity level between the print head and the cleaning vessel.
98. A method of cleaning a print head of any preceding clause comprising: applying a cleaning fluid comprising from 70 wt % to 99.9 wt % water and 0.1 wt % to 30 wt % of one or more organic solvents selected from the group consisting of dimethyl formamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), ethylene glycol, diethyl glycol, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, and propylene glycol to a surface of the print head having precipitant from a binder fluid comprising polyvinyl alcohol or a derivative thereof thereon; and removing used cleaning fluid from the surface of the print head after the cleaning fluid at least partially dissolves the precipitant from the surface.
99. The method of any preceding clause, wherein the cleaning fluid comprises from 0.5 wt % to 10 wt % of the one or more organic solvents.
100. The method of any preceding clause, wherein the organic solvent comprises DMF, NMP, DMSO, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, ethylene glycol, and combinations thereof.
101. The method of any preceding clause, wherein the cleaning fluid has a viscosity of less than 10 cP at 25° C.
102. The method of any preceding clause, wherein the cleaning fluid has a boiling point that is greater than or equal to 100° C. at 1 atm.
103. The method of any preceding clause, wherein the density of the cleaning fluid is from 0.900 to 1.400 g/cm3.
104. The method of any preceding clause, further comprising: passing at least a portion of the cleaning fluid through the print head having the precipitant from a binder fluid comprising polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid (PAA), or derivatives thereof therein.
105. The method of any preceding clause, further comprising: removing the used cleaning fluid from the print head after the cleaning fluid at least partially dissolves the precipitant from within the print head.
106. A method for monitoring a status of a cleaning fluid in a cleaning fluid system of any preceding clause, the method comprising: obtaining an initial value corresponding to at least one physical property selected from the group consisting of a density of the cleaning fluid, a viscosity of the cleaning fluid, a haze measurement, a surface tension, a color, a pH, a conductivity, and fluorescence of the cleaning fluid; obtaining a subsequent value corresponding to the at least one physical property of the cleaning fluid after a predetermined period of time of usage of the cleaning fluid to clean a print head; estimating one of an amount of contaminant in the cleaning fluid and an amount of evaporation of the cleaning fluid based on the difference between the subsequent value and the initial value of the physical property; selecting a cleaning fluid maintenance process is selected from a plurality of available maintenance processes based on the estimated one of the amount of contaminant and the amount of evaporation in the cleaning fluid; and performing the cleaning fluid maintenance process selected.
107. The method of any preceding clause, wherein performing the cleaning fluid maintenance process selected comprising adding water to the cleaning fluid.
108. The method of any preceding clause, wherein performing the cleaning fluid maintenance process selected comprises replacing a portion of the cleaning fluid containing contaminants with fresh cleaning fluid.
109. The method of any preceding clause, wherein performing the cleaning fluid maintenance process selected comprises replacing a majority of a volume of the cleaning fluid with fresh cleaning fluid.
110. The method of any preceding clause, wherein performing the cleaning fluid maintenance process selected comprises returning the cleaning fluid containing contaminants to a cleaning fluid reservoir in the cleaning fluid system.
111. The method of any preceding clause, wherein the at least one physical property is the density of the cleaning fluid, and wherein selecting the cleaning fluid maintenance process is further based on a viscosity, a surface tension, or both, of the cleaning fluid after the predetermined period of time.
112. The method of any preceding clause, wherein the cleaning fluid initially comprises from 70 wt % to 99.9 wt % water and 0.1 wt % to 30 wt % of one or more organic solvents selected from the group consisting of dimethyl formamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dimethyle-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), ethylene glycol, diethyl glycol, dipropylene glycol dimethyl ether, cyrene, dimethyl isosorbide, and propylene glycol.
113. The method of any preceding clause, wherein the contaminants comprise polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid (PAA), or derivatives thereof.
114. A method for monitoring the performance of an additive manufacturing device of any preceding clause using a fluorescent binder, the method comprising: exposing at least one layer comprising the fluorescent binder to electromagnetic radiation wherein the fluorescent binder includes fluorescent material which emits light in response to the electromagnetic radiation; sensing the emitted light intensity of the at least one layer after exposure; and computing a level of binder, solvent, or both within the layer versus time by utilizing a control system which correlates the sensed emitted light intensity to the level of binder, solvent, or both in the layer.
115. The method of any preceding clause, further comprising locating defects in the layer when the recorded emitted light intensity deviates from expected emitted light intensity values, or when the level of binder, solvent, or both deviates from expected levels.
116. The method of any preceding clause, further comprising performing diagnostic checks on the additive manufacturing device when defects are located.
117. The method of any preceding clause, wherein the electromagnetic radiation is UV radiation.
118. A fluid management system for supplying at least a binder fluid and a cleaning fluid of any preceding clause, the system comprising: a cleaning fluid path comprising at least one cleaning fluid reservoir, a pump configured to deliver the cleaning fluid from the at least one cleaning fluid reservoir to at least one cleaning station vessel, and a drain coupling the at least one cleaning station vessel to the at least one cleaning fluid reservoir; and a binder fluid path comprising at least one binder reservoir, a pump configured to deliver the binder fluid from the at least one binder reservoir through an ink supply system to a print head manifold, and a binder purge bin configured to receive binder fluid discharged by a print head coupled to the print head manifold.
119. The fluid management system of any preceding clause, wherein the binder purge bin is a first binder purge bin, the binder fluid path further comprising a second binder purge bin, wherein the first binder purge bin is located upstream from the at least one cleaning station vessel and the second binder purge bin is located downstream from the at least one cleaning station vessel along a path of the print head.
120. The fluid management system of any preceding clause, wherein the cleaning fluid path further comprises a filter positioned between the at least one cleaning fluid reservoir and the pump.
121. The fluid management system of any preceding clause, wherein the binder fluid path further comprises a filter positioned between the binder purge bin and the at least one binder reservoir.
122. The fluid management system of any preceding clause, wherein the binder fluid path further comprises an additional pump configured to pump fluid from the binder purge bin to the at least one binder reservoir.
123. The fluid management system of any preceding clause, wherein the cleaning fluid path further comprises a heater to heat the cleaning fluid.
124. The fluid management system of any preceding clause, wherein the cleaning fluid path further comprises a controller configured to send a signal to a valve positioned in the cleaning fluid path between the at least one cleaning station vessel and the at least one cleaning fluid reservoir to redirect a predetermined amount of the cleaning fluid flowing from the at least one cleaning station vessel to the at least one cleaning fluid reservoir to a waste tank, wherein the predetermined amount of the cleaning fluid contains at least some binder fluid.
125. The fluid management system of any preceding clause, wherein the controller is further configured to send a signal to the pump of the cleaning fluid path to adjust a flow rate of the cleaning fluid from the at least one cleaning fluid reservoir to the at least one cleaning station vessel.
126. The fluid management system of any preceding clause, wherein the controller is further configured to send a signal to a heater positioned between the pump and the at least one cleaning station vessel to adjust a temperature of the cleaning fluid.
127. The fluid management system of any preceding clause, wherein at least one of the pump of the cleaning fluid path and the pump of the binder fluid path is configured to move ferrous metals.
128. A method of using a fluid management system of any preceding clause comprising: continuously recirculating a binder fluid through a binder fluid path comprising at least one binder reservoir, a pump, and a binder purge bin, wherein: the pump delivers the binder fluid from the at least one binder reservoir through an ink supply system to a print head manifold; and the binder purge bin receives binder fluid discharged by a print head coupled to the print head manifold; delivering, using a pump, a cleaning fluid from at least one cleaning fluid reservoir to at least one cleaning station vessel; receiving, at a waste tank, a first portion of the cleaning fluid from the at least one cleaning station vessel; returning a second portion of the cleaning fluid from the at least one cleaning station vessel to the at least one cleaning fluid reservoir; and diverting a predetermined amount of the second portion of the cleaning fluid to the waste tank based on a level of contamination of the cleaning fluid with the binder fluid.
129. The method of any preceding clause, wherein diverting the predetermined amount of the second portion of the cleaning fluid comprises sending a signal to a valve positioned between the at least one cleaning station vessel, the at least one cleaning fluid reservoir, and the waste tank to divert the predetermined amount of the second portion of the cleaning fluid flowing from the at least one cleaning station vessel to the at least one cleaning fluid reservoir to the waste tank.
130. The method of any preceding clause, wherein the binder purge bin comprises an overflow outlet for redirecting the binder fluid from the binder purge bin to the at least one binder reservoir.
131. The method of any preceding clause, wherein continuously recirculating the binder fluid comprises pumping the binder fluid from the binder purge bin to the at least one binder reservoir.
132. The method of any preceding clause, wherein the binder fluid path further comprises a filter positioned between the binder purge bin and the at least one binder reservoir.
133. The method of any preceding clause, wherein the filter is positioned between the binder purge bin and the pump of the binder fluid path.
134. A wet wiper apparatus of any preceding clause comprising: a wet wiper body having a top side and a bottom side; a first wiper blade vertically extending from the top side of the wet wiper body; and a fluid channel horizontally extending from a first end of the wet wiper body to a second end of the wet wiper body, the fluid channel having an open top to allow fluid flow out of the fluid channel.
135. The wet wiper apparatus of any preceding clause, further comprising a second wiper blade vertically extending from the top side of the wet wiper body and spaced apart from the first wiper blade.
136. The wet wiper apparatus of any preceding clause, wherein the fluid channel is positioned between the first wiper blade and the second wiper blade.
137. The wet wiper apparatus of any preceding clause, wherein the first wiper blade and the second wiper blade extend from a first end of the wet wiper apparatus to a second end of the wet wiper apparatus.
138. The wet wiper apparatus of any preceding clause, further comprising a pair of walls extending between the first wiper blade and the second wiper blade from a base of the wet wiper apparatus to a top of each of the first wiper blade and the second wiper blade.
139. The wet wiper apparatus of any preceding clause, wherein fluid channel defines a recessed path within the wet wiper body.
140. The wet wiper apparatus of any preceding clause, further comprising a cleaning manifold extending below the fluid channel within the wet wiper body, wherein the cleaning manifold comprises a plurality of fluid ports configured to provide cleaning fluid to the fluid channel.
141. The wet wiper apparatus of any preceding clause, further comprising a plurality of cleaning fluid inlets operable to receive the cleaning fluid and provide the cleaning fluid to the cleaning manifold.
142. The wet wiper apparatus of any preceding clause, wherein the plurality of cleaning fluid inlets comprise fluid conduits extending vertically upward through the bottom side of the wet wiper body.
143. The wet wiper apparatus of any preceding clause, wherein the plurality of cleaning fluid inlets comprise fluid conduits extending from a side of the wet wiper body adjacent to the top side and the bottom side of the wet wiper body.
144. The wet wiper apparatus of any preceding clause, further comprising a cleaning manifold extending below the fluid channel within the wet wiper body, wherein the cleaning manifold comprises a fluid port extending from the first end of the wet wiper apparatus to the second end of the wet wiper apparatus configured to provide cleaning fluid to the fluid channel.
145. The wet wiper apparatus of any preceding clause, further comprising at least one motion coupler extending from the wet wiper apparatus and configured to couple the wet wiper apparatus to a cleaning station for vertical motion therein.
146. A wet wiper apparatus of any preceding clause comprising: a wet wiper body having a top side and a bottom side; a wiper blade vertically extending from a top side of the wet wiper body; a manifold comprising at least one fluid port, the manifold being configured to deliver cleaning fluid to the top side of the wet wiper body; and cleaning fluid inlets extending through the wet wiper body, wherein the cleaning fluid inlets are in fluid communication with the at least one fluid port of the manifold.
147. The wet wiper apparatus of any preceding clause, wherein the wiper blade is a first wiper blade, and the wet wiper apparatus further comprises a second wiper blade vertically extending from a top side of the wet wiper body.
148. The wet wiper apparatus of any preceding clause, wherein the at least one fluid port is disposed between the first and second wiper blades along the wet wiper body.
149. The wet wiper apparatus of any preceding clause, further comprising a fluid channel formed in the wet wiper body and positioned between the first wiper blade and the second wiper blade, wherein the fluid channel is in fluid communication with the at least one fluid port of the manifold.
150. The wet wiper apparatus of any preceding clause, wherein the fluid channel comprises an open top to allow fluid flow out of the fluid channel.
151. The wet wiper apparatus of any preceding clause, wherein the cleaning fluid inlets extend vertically upward through the bottom side of the wet wiper body.
152. The wet wiper apparatus of any preceding clause, further comprising a pair of walls extending between the first wiper blade and the second wiper blade from the top side of the wet wiper apparatus to a top of each of the first wiper blade and the second wiper blade.
153. The wet wiper apparatus of any preceding clause, further comprising at least one motion coupler extending from the wet wiper apparatus and configured to couple the wet wiper apparatus to a cleaning station for vertical motion therein.
154. A wiper array of any preceding clause comprising: a wiper mounting member extending along a longitudinal axis; and a plurality of wiper blades mounted to the wiper mounting member, wherein a length of each of the plurality of wiper blades extends in a direction that at an angle of greater than 0 and less than 90° relative to the longitudinal axis; wherein each of the plurality of wiper blades has an overlap of at least part of its length with the length of an adjacent wiper blade in a direction orthogonal to the longitudinal axis.
155. The wiper array of any preceding clause, wherein a length of each of the plurality of wiper blades is oriented at an angle of from 5 to 50° with respect to the longitudinal axis.
156. The wiper array of any preceding clause, wherein the wiper mounting member comprises a plurality of channels formed in a top face of the wiper mounting member, each channel shaped to receive one of the plurality of wiper blades.
157. The wiper array of any preceding clause, wherein each of the plurality of wiper blades has an overlap of at least 30% of its length with the length of an adjacent wiper blade in a direction orthogonal to the longitudinal axis.
158. The wiper array of any preceding clause, wherein each of the plurality of wiper blades comprises a blade and a body member from which the blade extends.
159. A cleaning station of any preceding clause comprising: a cleaning station vessel containing a volume of a cleaning fluid therein; a wiper assembly comprising a wiper mounting member extending along a longitudinal axis; a first actuator coupled proximate a first end of the wiper assembly; and a second actuator coupled proximate a second end of the wiper assembly; wherein the first actuator and the second actuator are independently operable to raise or lower a corresponding end of the wiper assembly into the volume of the cleaning fluid.
160. The cleaning station of any preceding clause, the wiper assembly being a first wiper assembly, wherein the cleaning station further comprises a second wiper assembly.
161. The cleaning station of any preceding clause, wherein at least one of the first wiper assembly and the second wiper assembly further comprises: a plurality of wiper blades mounted to the wiper mounting member, wherein a length of each of the plurality of wiper blades extends in a direction that at an angle of greater than 0 and less than 90° relative to the longitudinal axis; wherein each of the plurality of wiper blades has an overlap of at least part of its length with the length of an adjacent wiper blade in a direction orthogonal to the longitudinal axis.
162. The cleaning station of any preceding clause, wherein each of the plurality of wiper blades comprises a blade and a body member from which the blade extends.
163. The cleaning station of any preceding clause, wherein the first and second actuators are linear actuators.
164. The cleaning station of any preceding clause, wherein the first and second actuators are electric actuators.
165. The cleaning station of any preceding clause, wherein the electric actuators are operable to agitate the wiper assembly.
166. The cleaning station of any preceding clause, wherein the electric actuators are independently operable to raise or lower the corresponding end of the wiper assembly at a plurality of speeds.
167. A method of cleaning a print head of any preceding clause comprising: actuating a first actuator coupled proximate a first end of a wiper assembly to raise the first end of the wiper assembly above a volume of a cleaning fluid in a cleaning station vessel; after the first end of the wiper assembly is raised above the volume of the cleaning fluid, actuating a second actuator coupled proximate a second end of the wiper assembly to raise the second end of the wiper assembly above the volume of the cleaning fluid in the cleaning station vessel; passing the print head over the cleaning station vessel and the wiper assembly, thereby enabling the wiper assembly to remove cleaning fluid from the print head; actuating the first and second actuators to lower the first and second ends of the wiper assembly into the volume of the cleaning fluid in the cleaning station vessel.
168. The method of any preceding clause, wherein the wiper assembly comprises a wiper mounting member and a plurality of wiper blades mounted to the wiper mounting member, wherein a length of each of the plurality of wiper blades extends in a direction that at an angle of greater than 0 and less than 90° relative to a longitudinal axis along which the wiper mounting member extends; wherein each of the plurality of wiper blades has an overlap of at least part of its length with the length of an adjacent wiper blade in a direction orthogonal to the longitudinal axis; and wherein passing the print head over the cleaning station vessel and the wiper assembly comprises passing the print head in a direction orthogonal to the longitudinal axis.
169. The method of any preceding clause, wherein actuating the second actuator to lower the second end of the wiper assembly into the volume of the cleaning fluid in the cleaning station vessel is completed before or after actuating the first actuator to lower the first end of the wiper assembly into the volume of the cleaning fluid in the cleaning station vessel.
170. The method of any preceding clause, wherein actuating the second actuator to lower the second end of the wiper assembly into the volume of the cleaning fluid in the cleaning station vessel is completed while actuating the first actuator to lower the first end of the wiper assembly into the volume of the cleaning fluid in the cleaning station vessel.
171. The method of any preceding clause, wherein the first and second actuators are electric actuators.
172. The method of any preceding clause, further comprising actuating the electric actuators to agitate the wiper assembly.
173. A manufacturing apparatus any preceding clause, comprising: a printing head comprising a plurality of jet nozzles spaced apart from one another in a direction transverse to a longitudinal axis, wherein a distance from a first jet nozzle to a second jet nozzle positioned adjacent the first jet nozzle of the plurality of jet nozzles defines a jet-spacing; a printing head position control assembly comprising a first actuator assembly configured to move the printing head along the longitudinal axis and a second actuator assembly configured to move the printing head along a latitudinal axis; and an electronic control unit communicatively coupled to the printing head position control assembly, the electronic control unit is configured to: cause select ones of the plurality of jet nozzles to dispense one or more drops of binder while the printing head traverses a first pass trajectory along the longitudinal axis in a first direction, index the printing head to a second pass trajectory along the latitudinal axis by an index distance greater than zero and less than the jet-spacing, and cause select ones of the plurality of jet nozzles to dispense one or more drops of binder while the printing head traverses the second pass trajectory along the longitudinal axis in a second direction opposite the first direction.
174. The manufacturing apparatus of any preceding clause, wherein multiple drops of binder are dispensed within a pixel defining a 2-dimensional spatial portion of a layer of build material traversed by the printing head.
175. The manufacturing apparatus of any preceding clause, wherein the multiple drops of binder dispensed within the pixel vary in drop volume.
176. The manufacturing apparatus of any preceding clause, wherein the multiple drops of binder dispensed within the pixel vary in drop volume and location within the pixel.
177. The manufacturing apparatus of any preceding clause, wherein a total amount of binder predefined for dispensing within a pixel is dispensed in fractions of the total amount of binder over at least two passes of the printing head.
178. The manufacturing apparatus of any preceding clause, wherein the index distance is one-half the jet-spacing.
179. The manufacturing apparatus of any preceding clause, wherein the index distance is an integer multiple of a fractional value of the jet-spacing.
180. The manufacturing apparatus of any preceding clause, wherein the printing head comprises a first print head row comprising a plurality of print heads sequentially spaced apart from one another in a direction transverse to a working axis, the manufacturing apparatus further comprising: an actuator coupled to a first print head of the plurality of print heads, the actuator configured to move the first print head along a latitudinal axis.
181. The manufacturing apparatus of any preceding clause, wherein the electronic control unit is further configured to: index one or more of the plurality of print heads to the second pass trajectory along the latitudinal axis by an index distance greater than zero and less than the j et-spacing.
182. The manufacturing apparatus of any preceding clause, wherein the actuator is one of a plurality of actuators, wherein each actuator of the plurality of actuators is coupled to a print head of the plurality of print heads.
183. A manufacturing apparatus of any preceding clause, comprising: at least one printing head comprising a plurality of jet nozzles spaced apart from one another in a direction transverse to a longitudinal axis, wherein a distance from a first jet nozzle to a second jet nozzle positioned adjacent the first jet nozzle of the plurality of jet nozzles defines a jet-spacing; a printing head position control assembly comprising a first actuator configured to move the printing head along the longitudinal axis and a second actuator configured to move the printing head along a latitudinal axis; and an electronic control unit communicatively coupled to the printing head position control assembly, the electronic control unit is configured to: cause select ones of the plurality of jet nozzles to dispense one or more drops of binder to a powder layer in a deposition pattern defined by a slicing engine as the printing head traverses along the longitudinal axis applying binder, wherein the first jet nozzle of the plurality of jet nozzles corresponds to a first trajectory assigned by the slicing engine, index the printing head by an index distance along the latitudinal axis such that the first jet nozzle corresponds to a second pass trajectory and another jet nozzle corresponds to the first trajectory assigned by the slicing engine, and cause the indexed printing head to traverse along the longitudinal axis and apply binder to the powder layer in the deposition pattern defined by the slicing engine.
184. The manufacturing apparatus of any preceding clause, wherein the step of indexing the printing head along the latitudinal axis occurs between a first pass and a second pass over the same layer of powder.
185. The manufacturing apparatus of any preceding clause, wherein the step of indexing the printing head along the latitudinal axis occurs between after application of binder to a first layer of powder and before application of binder to a subsequent layer of powder.
186. The manufacturing apparatus of any preceding clause, further comprising an in situ monitoring system configured to: determine a malfunction of one or more jet nozzles of the plurality of jet nozzles, and provide a notification signal to the electronic control unit identifying the one or more malfunctioning jet nozzles.
187. The manufacturing apparatus of any preceding clause, wherein the electronic control unit is further configured to: develop one or more indexing commands for indexing the printing head between predefined passes such that a malfunctioning jet nozzle is configured to not traverse the same trajectory during consecutive passes while determined to be in a malfunctioning state.
188. The manufacturing apparatus of any preceding clause, wherein the electronic control unit is further configured to: develop a one or more indexing commands for indexing the printing head between predefined passes such that a malfunctioning jet nozzle does not traverse a trajectory defining an edge of the deposition pattern for a printed part.
189. The manufacturing apparatus of any preceding clause, wherein the slicing engine defines at least the predetermined number of layers and the deposition pattern of binder for printing a part.
190. The manufacturing apparatus of any preceding clause, further comprising: wherein the printing head comprises a first print head row comprising a plurality of print heads sequentially spaced apart from one another in a direction transverse to a working axis; and an actuator coupled to a first print head of the plurality of print heads, the actuator configured to move the first print head along a latitudinal axis.
191. The manufacturing apparatus of any preceding clause, wherein the electronic control unit is further configured to: index one or more of the plurality of print heads to the second pass trajectory along the latitudinal axis by an index distance along the latitudinal axis such that the first jet nozzle corresponds to the second pass trajectory and another jet nozzle corresponds to the first trajectory assigned by the slicing engine.
192. The manufacturing apparatus of any preceding clause, wherein the actuator is one of a plurality of actuators, wherein each actuator of the plurality of actuators is coupled to a print head of the plurality of print heads.
193. A manufacturing apparatus of any preceding clause, comprising: a printing head comprising a plurality of jet nozzles spaced apart from one another in a direction transverse to a longitudinal axis; a printing head position control assembly comprising a first actuator configured to move the printing head along the longitudinal axis; and an electronic control unit communicatively coupled to the printing head position control assembly, the electronic control unit configured to: cause select ones of the plurality of jet nozzles to dispense a predetermined volume of binder to a powder layer in a deposition pattern defined by a slicing engine as the printing head traverses the longitudinal axis applying binder, wherein an amount of binder dispensed in a first portion of powder in a first layer is less than the amount of binder dispensed in a portion of powder in a second layer located above the first portion of powder in the first layer.
194. The manufacturing apparatus of any preceding clause, wherein the amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers of powder progressively increases to a predetermined volume.
195. The manufacturing apparatus of any preceding clause, wherein the amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers of powder progressively increases over an attenuation length defined by a predetermined number of layers of powder.
196. The manufacturing apparatus of any preceding clause, wherein the amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers of powder progressively increases over an attenuation length defined by a predetermined number of layers of powder when the predetermined number of layers is greater than a predetermined thickness threshold.
197. The manufacturing apparatus of any preceding clause, wherein the amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers is based upon one or more properties of a powder material.
198. The manufacturing apparatus of any preceding clause, wherein the amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers is based upon a packing density of a powder material.
199. The manufacturing apparatus of any preceding clause, wherein the amount of binder dispensed in successive vertically aligned portions of powder in subsequent layers is based upon an amount of time a binder wicks before setting.
200. An actuator assembly for distributing build material and depositing binder material in an additive manufacturing apparatus of any preceding clause comprising an upper support; a lower support spaced from the upper support in a vertical direction, the upper support and the lower support extending in a horizontal direction; a recoat head for distributing build material; a print head for depositing binder material; a recoat head actuator coupled to the recoat head and one of the upper support and the lower support, the recoat head actuator comprising a recoat motion axis, wherein the recoat head actuator is bi-directionally actuatable along the recoat motion axis thereby effecting bi-directional movement of the recoat head; and a print head actuator coupled to the print head and the other of the upper support and the lower support, the print head actuator comprising a print motion axis, wherein the print head actuator is bi-directionally actuatable along the print motion axis thereby effecting bi-directional movement of the print head, wherein the recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in the vertical direction.
201. The actuator assembly of any preceding clause, wherein the upper support and the lower support are positioned on opposite sides of a support rail.
202. The actuator assembly of any preceding clause, wherein the recoat motion axis and the print motion axis are in the same vertical plane.
203. The actuator assembly of any preceding clause, wherein the actuator assembly further comprises an intermediate support positioned between the upper support and the lower support, the intermediate support extending in the horizontal direction; a process accessory; and an accessory actuator coupled to the process accessory and the intermediate support, the accessory actuator comprising an accessory motion axis, wherein the accessory actuator is bi-directionally actuatable along the accessory motion axis thereby effecting bi-directional movement of the process accessory, wherein the recoat motion axis, the print motion axis, and the accessory motion axis are parallel to one another and spaced apart from one another in the vertical direction.
204. The actuator assembly of any preceding clause, wherein the process accessory comprises a sensor, an energy source, an end effector or combinations thereof.
205. The actuator assembly of any preceding clause, wherein the sensor is at least one of an image sensor, a thermal detector, a pyrometer, a profilometer, and an ultrasonic detector.
206. The actuator assembly of any preceding clause, wherein sensor is at least one of an infrared heater, an ultraviolet lamp, and a laser light source.
207. The actuator assembly of any preceding clause, wherein: the recoat head comprises a recoat home position; the print head comprises a print home position spaced apart from the recoat home position in the horizontal direction; and a control system is communicatively coupled to the recoat head actuator and the print head actuator, the control system comprising a processor and a non-transitory memory storing computer readable and executable instructions that, when executed by the processor, cause: the recoat head actuator to advance the recoat head from the recoat home position towards the print home position at a recoat advance rate; the recoat head actuator to return the recoat head to the recoat home position at a recoat return rate; the print head actuator to advance the print head from the print home position of the print head towards the recoat home position at a print advance rate; and the print head actuator to return the print head to the print home position at a print return rate.
208. The actuator assembly of any preceding clause, wherein the recoat return rate is greater than the recoat advance rate.
209. The actuator assembly of any preceding clause, wherein the print return rate is greater than or equal to the print advance rate.
210. The actuator assembly of any preceding clause, wherein the print return rate is less than or equal to the print advance rate.
211. The actuator assembly of any preceding clause, wherein the recoat advance rate comprises: an initial recoat advance rate; and a distribution advance rate, wherein the initial recoat advance rate is greater than the distribution advance rate.
212. The actuator assembly of any preceding clause, wherein the print advance rate comprises: an initial print advance rate; and a deposition advance rate, wherein the initial print advance rate is greater than the deposition advance rate.
213. The actuator assembly of any preceding clause, wherein the print return rate comprises: a deposition return rate; and a print complete return rate, wherein the print complete return rate is greater than the deposition return rate.
214. The actuator assembly of any preceding clause, wherein the print head is advanced from the print home position towards the recoat home position while the recoat head is returned to the recoat home position.
215. The actuator assembly of any preceding clause, wherein the recoat head is advanced from the recoat home position towards the print home position while the print head is returned to the print home position of the print head.
216. The actuator assembly of any preceding clause, wherein the recoat head comprises at least one of a wiper and a roller for distributing build material.
217. The actuator assembly of any preceding clause, wherein the recoat head comprises a leading roller and a trailing roller for distributing build material.
218. The actuator assembly of any preceding clause, wherein the leading roller rotates in a first direction and the trailing roller rotates in a second direction opposite the first direction.
219. The actuator assembly of any preceding clause, wherein the recoat head and/or the print head comprises at least one energy source.
220. The actuator assembly of any preceding clause, wherein the print head is a thermal print head or a piezo print head.
221. The actuator assembly of any preceding clause, wherein the print head is fixed in directions orthogonal to the print motion axis.
222. An additive manufacturing apparatus of any preceding clause, comprising: a cleaning station comprising a cleaning station cycle time; a build platform; a recoat head for distributing build material, the recoat head coupled to a recoat head actuator comprising a recoat motion axis, the recoat head and recoat head actuator comprising a recoat cycle time; and a print head for depositing binder material, the print head coupled to a print head actuator comprising a print motion axis, the print head and the print head actuator comprising a print cycle time, wherein: the recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in a vertical direction; and the additive manufacturing apparatus comprises an overall build cycle time that is less than the sum of cleaning station cycle time, the recoat cycle time, and the print cycle time.
223. The apparatus of any preceding clause, wherein: the cleaning station cycle time overlaps with both the print cycle time and the recoat cycle time TRH; and the overall build cycle time is less than the sum of the recoat cycle time and the print cycle time.
224. The apparatus of any preceding clause, wherein: the recoat head actuator is coupled to one of an upper support and a lower support; and the print head actuator is coupled to the other of the upper support and the lower support, wherein the upper support and the lower support are positioned above the build platform and extend in a horizontal direction.
225. The apparatus of any preceding clause, wherein the recoat motion axis and the print motion axis are located in the same vertical plane.
224. The apparatus of any preceding clause, wherein: the recoat head comprises a recoat home position; the print head comprises a print home position spaced apart from the recoat home position in a horizontal direction; and further comprising a control system communicatively coupled to the recoat head actuator and the print head actuator, the control system comprising a processor and a non-transitory memory storing computer readable and executable instructions that, when executed by the processor, cause: the recoat head actuator to advance the recoat head from the recoat home position towards the print home position at a recoat advance rate; the recoat head actuator to return the recoat head to the recoat home position at a recoat return rate; the print head actuator to advance the print head from the print home position of the print head towards the recoat home position at a print advance rate; and the print head actuator to return the print head to the print home position at a print return rate, wherein: the recoat return rate is greater than the recoat advance rate; and the print return rate is greater than the print advance rate.
225. The apparatus of any preceding clause, wherein the recoat advance rate comprises: an initial recoat advance rate; and a distribution advance rate, wherein the initial recoat advance rate is greater than the distribution advance rate.
226. The apparatus of any preceding clause, wherein the print advance rate comprises: an initial print advance rate; and a deposition advance rate, wherein the initial print advance rate is greater than the deposition advance rate.
227. The apparatus of any preceding clause, wherein the print return rate comprises: a deposition return rate; and a print complete return rate, wherein the print complete return rate is greater than the deposition return rate.
228. The apparatus of any preceding clause, wherein the print head is advanced from the print home position towards the recoat home position while the recoat head is returned to the recoat home position.
229. The apparatus of any preceding clause, wherein the recoat head is advanced from the recoat home position towards the print home position while the print head is returned to the print home position of the print head.
230. The apparatus of any preceding clause, further comprising a supply platform bi-directionally actuatable along a vertical axis, wherein the build platform is positioned between the cleaning station and the supply platform.
231. The apparatus of any preceding clause, further comprising a build material hopper coupled to the recoat head.
232. The apparatus of any preceding clause, further comprising a build material hopper positioned over the build platform.
233. A method of building an object by additive manufacturing of any preceding clause, the method comprising: distributing a new layer of build material on a build platform with a recoat head coupled to a recoat head actuator, the recoat head actuator comprising a recoat motion axis whereby actuation of the recoat head actuator along the recoat motion axis in a first recoat direction causes the recoat head to distribute the new layer of build material on the build platform; and depositing a binder material on the new layer of build material with a print head coupled to a print head actuator, the print head actuator comprising a print motion axis whereby the binder material is deposited with the print head by actuating the print head actuator along the print motion axis in a first print direction opposite the first recoat direction, wherein the recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in a vertical direction.
234. The method of any preceding clause, wherein: the recoat head and recoat head actuator comprise a recoat cycle time during which the new layer of build material is distributed on the build platform; and the print head and print head actuator comprise a print cycle time during which the binder material is deposited on the new layer of build material, wherein the print cycle time overlaps with the recoat cycle time.
235. The method of any preceding clause, wherein the recoat motion axis and the print motion axis are in the same vertical plane.
236. The method of any preceding clause, wherein: the recoat head is actuated by the recoat head actuator along the recoat motion axis at a recoat advance rate; and the print head is actuated by the print head actuator along the print motion axis at a print advance rate, wherein the print advance rate is greater than the recoat advance rate.
237. The method of any preceding clause, wherein the recoat advance rate comprises: an initial recoat advance rate; and a distribution advance rate, wherein the initial recoat advance rate is greater than the distribution advance rate.
238. The method of any preceding clause, wherein the print advance rate comprises: an initial print advance rate; and a deposition advance rate, wherein the initial print advance rate is greater than the deposition advance rate.
239. The method of any preceding clause, wherein: after the distributing the new layer of build material on the build platform, the recoat head is actuated by the recoat head actuator along the recoat motion axis in a second recoat direction opposite the first recoat direction at a recoat return rate.
240. The method of any preceding clause, wherein the recoat return rate is greater than the recoat advance rate.
241. The method of any preceding clause, wherein the print head is actuated by the print head actuator along the print motion axis in the first print direction as the recoat head is actuated by the recoat head actuator along the recoat motion axis in the second recoat direction.
242. The method of any preceding clause, wherein: after the depositing the binder material on the new layer of build material, the print head is actuated by the print head actuator along the print motion axis in a second print direction opposite the first print direction at a print return rate.
243. The method of any preceding clause, wherein the print return rate is greater than the print advance rate.
244. The method of any preceding clause, wherein the print head deposits binder material on the new layer of build material as the print head is actuated by the print head actuator along the print motion axis in the second print direction.
245. The method of any preceding clause, wherein the print return rate comprises: a deposition return rate; and a print complete return rate, wherein the print complete return rate is greater than the deposition return rate.
246. The method of any preceding clause, wherein the distributing the new layer of build material on the build platform comprises spreading build material from a supply platform to the build platform with at least one of a wiper or a roller coupled to the recoat head.
247. The method of any preceding clause, wherein the distributing the new layer of build material on the build platform comprises: spreading build material from a supply platform to the build platform with a first roller coupled to the recoat head; and compacting build material on the build platform with a second roller coupled to the recoat head, wherein the first roller and the second roller are rotated in opposite directions.
248. The method of any preceding clause, wherein the distributing the new layer of build material on the build platform further comprises heating the new layer of build material with an energy source coupled to the recoat head.
249. The method of any preceding clause, wherein the new layer of build material is distributed over a previous layer of build material disposed on the build platform and the method further comprises curing binder material deposited on the previous layer of build material prior to the distributing the new layer of build material.
250. The method of any preceding clause, wherein the binder material deposited on the previous layer of build material is cured with an energy source coupled to the recoat head.
251. An actuator assembly for distributing build material and depositing binder material in an additive manufacturing apparatus of any preceding clause, the assembly comprising: a support extending in a horizontal direction; a recoat head for distributing build material; a print head for depositing binder material; a recoat head actuator coupled to the recoat head and the support, the recoat head actuator comprising a recoat motion axis, wherein the recoat head actuator is bi-directionally actuatable along the recoat motion axis thereby effecting bi-directional movement of the recoat head; and a print head actuator coupled to the print head and the support, the print head actuator comprising a print motion axis, wherein the print head actuator is bi-directionally actuatable along the print motion axis thereby effecting bi-directional movement of the print head, wherein the recoat motion axis and the print motion axis are co-linear and bi-directional actuation of the print head actuator on the print motion axis and bi-directional actuation of the recoat head actuator on the recoat motion axis are independent of one another.
252. The actuator assembly of any preceding clause, wherein: the support is positioned in a first vertical plane; and the recoat motion axis and the print motion axis are positioned in a second vertical plane parallel to the first vertical plane.
253. The actuator assembly of any preceding clause, wherein: the print head is cantilevered from the support; and the recoat head is cantilevered from the support.
254. An actuator assembly for distributing build material and depositing binder material in an additive manufacturing apparatus of any preceding clause, the assembly comprising: an upper support; a lower support spaced from the upper support in a vertical direction; an intermediate support positioned between the upper support and the lower support and space from the upper support and the lower support in a vertical direction, the upper support, the lower support, and the intermediate support extending in a horizontal direction; a recoat head for distributing build material; a print head for depositing binder material; a process accessory; a recoat head actuator coupled to the recoat head and one of the upper support, the lower support, and the intermediate support, the recoat head actuator comprising a recoat motion axis, wherein the recoat head actuator is bi-directionally actuatable along the recoat motion axis thereby effecting bi-directional movement of the recoat head; a print head actuator coupled to the print head and another of the upper support, the lower support, and the intermediate support, the print head actuator comprising a print motion axis, wherein the print head actuator is bi-directionally actuatable along the print motion axis thereby effecting bi-directional movement of the print head; and an accessory actuator coupled to the process accessory and the other of the upper support, the lower support, and the intermediate support, the accessory actuator comprising an accessory motion axis, wherein the accessory actuator is bi-directionally actuatable along the accessory motion axis thereby effecting bi-directional movement of the process accessory, wherein the recoat motion axis, the print motion axis, and the accessory motion axis are parallel to one another and spaced apart from one another in the vertical direction.
255. The actuator assembly of any preceding clause, wherein the process accessory comprises a sensor, an energy source, an end effector or combinations thereof.
256. The actuator assembly of any preceding clause, wherein the sensor is at least one of an image sensor, a thermal detector, a pyrometer, a profilometer, and an ultrasonic detector.
257. The actuator assembly of any preceding clause, wherein the energy source is at least one of an infrared heater, an ultraviolet lamp, and a laser light source.
258. A build receptacle for an additive manufacturing apparatus which may be used in conjunction with the actuator assemblies, additive manufacturing apparatuses, and methods of any preceding clause, comprising a housing comprising a sidewall at least partially enclosing a build chamber, and a build platform positioned within the build chamber. A position of the build platform is slidably adjustable within the build chamber in a vertical direction from a lower position to one of a plurality of upper positions and from the one of the plurality of upper positions to the lower position. The build receptacle further comprises a plurality of heating elements disposed around the build chamber.
259. The build receptacle of any preceding clause, wherein a seal is disposed between the build platform and an interior surface of the sidewall.
260. The build receptacle of any preceding clause, wherein the seal comprises a core portion and an enveloping portion. The enveloping portion at least partially encloses the core portion, the core portion comprises polytetrafluoroethylene, and the enveloping portion comprises fibrous material.
261. The build receptacle of any preceding clause, wherein the enveloping portion comprises felt.
262. The build receptacle of any preceding clause, wherein the core portion comprises a braided polytetrafluoroethylene packing seal.
263. The build receptacle of any preceding clause, wherein the build platform comprises a seal seat in an edge of the build platform, the seal positioned in the seal seat such that the seal is disposed between the build platform and the interior surface of the sidewall.
264. The build receptacle of any preceding clause, further comprising a seal frame enclosing at least a portion of the seal seat.
265. The build receptacle of any preceding clause, wherein the housing further comprises a plurality of retention tabs extending from the sidewall into the build chamber proximate a bottom of the sidewall.
266. The build receptacle of any preceding clause, wherein the build platform is seated on the retention tabs when the build platform is in the lower position.
267. The build receptacle of any preceding clause, wherein the housing comprises a flange extending from the sidewall proximate a top of the sidewall.
268. The build receptacle of any preceding clause, further comprising a plurality of lift points located on the flange, the sidewall, or both, the lift points facilitating lifting and lowering the build receptacle.
269. The build receptacle of any preceding clause, wherein each lift point of the plurality of lift points comprises a handle extending from the flange, the sidewall, or both.
270. The build receptacle of any preceding clause, wherein each lift point of the plurality of lift points comprises a lift flange extending from the sidewall.
271. The build receptacle of any preceding clause, wherein the plurality of heating elements are disposed on an exterior surface of the sidewall.
272. The build receptacle of any preceding clause, wherein the plurality of heating elements are disposed within the sidewall.
273. The build receptacle of any preceding clause, wherein the plurality of heating elements are arranged in heating zones and each heating zone is independently actuatable.
274. The build receptacle of any preceding clause, wherein each heating zone is spaced apart from an adjacent heating zone in the vertical direction.
275. The build receptacle of any preceding clause, wherein each heating zone comprises at least one heating element arranged in a horizontal band.
276. The build receptacle of any preceding clause, further comprising at least one cover affixed to an exterior surface of the sidewall such that the plurality of heating elements are disposed between the cover and the exterior surface of the sidewall.
277. The build receptacle of any preceding clause, further comprising insulation positioned between the at least one cover and the plurality of heating elements.
278. The build receptacle of any preceding clause, wherein an exterior surface of the sidewall comprises grooves and the plurality of heating elements are positioned in the grooves.
279. The build receptacle of any preceding clause, further comprising a plurality of temperature sensors arranged around the build chamber.
280. The build receptacle of any preceding clause, further comprising a plurality of temperature sensors arranged around the build chamber.
281. The build receptacle of any preceding clause, wherein the temperature sensors are disposed within the sidewall.
282. The build receptacle of any preceding clause, wherein the temperature sensors are resistance temperature detectors coupled to individual ones of the plurality of heating elements.
283. The build receptacle of any preceding clause, wherein two resistance temperature detectors are coupled to individual ones of the plurality of heating elements.
284. The build receptacle of any preceding clause, wherein two resistance temperature detectors are coupled to individual ones of the plurality of heating elements.
285. The build receptacle of any preceding clause, wherein the electrical connectors supply power to the plurality of heating elements and transmit electrical signals from the build receptacle indicative of a temperature of the sidewall of the build receptacle.
286. The build receptacle of any preceding clause, further comprising a lid at least partially enclosing the build chamber.
287. The build receptacle of any preceding clause, wherein a bottom surface of the build platform further comprises connectors for coupling the build platform to a lift system for actuating the build platform from the lower position to one of the plurality of upper positions and from the one of the plurality of upper positions to the lower position.
287. The build receptacle of any preceding clause, further comprising a second plurality of heating elements positioned below a top surface of the build platform.
288. The build receptacle of any preceding clause, wherein the second plurality of heating elements are positioned below a bottom surface of the build platform.
289. An additive manufacturing apparatus comprising a build receptacle and a lift system which may be used in conjunction with the apparatuses, assemblies, and methods of any preceding clause. The build receptacle comprises a housing comprising a sidewall at least partially enclosing a build chamber, and a build platform positioned within the build chamber. A position of the build platform is slidably adjustable within the build chamber in a vertical direction from a lower position to one of a plurality of upper positions and from the one of the plurality of upper positions to the lower position. The lift system is a position of the build platform is slidably adjustable within the build chamber in a vertical direction from a lower position to one of a plurality of upper positions and from the one of the plurality of upper positions to the lower position.
290. The additive manufacturing apparatus of any preceding clause, wherein the build platform actuator comprises a ball screw coupled to a motor.
291. The additive manufacturing apparatus of any preceding clause, wherein the build platform actuator further comprises a drive linkage connecting the ball screw to an armature of the motor such that the ball screw is rotatably coupled to the armature of the motor.
292. The additive manufacturing apparatus of any preceding clause, wherein when the lift system is coupled to the build platform a bottom surface of the build platform is in contact with an upper surface of the heating platen.
293. The additive manufacturing apparatus of any preceding clause, wherein the lift system further comprises a plurality of vertical guides coupled to the heating platen.
294. The additive manufacturing apparatus of any preceding clause, wherein the lift system further comprises a heating platen position sensor for detecting a vertical position of the heating platen.
295. The additive manufacturing apparatus of any preceding clause, wherein the heating platen position sensor is positioned proximate to a lower end of the lift system and comprises a limit switch.
296. The additive manufacturing apparatus of any preceding clause, wherein the lift system further comprises a build platform position sensor for detecting a vertical position of the build platform.
297. The additive manufacturing apparatus of any preceding clause, wherein the lift system further comprises a build platform position sensor for detecting a vertical position of the build platform.
298. The additive manufacturing apparatus of any preceding clause, wherein a bottom surface of the build platform further comprises connectors to couple to the lift system; and an upper surface of the heating platen comprises corresponding connectors to couple to the bottom surface of the build platform.
299. The additive manufacturing apparatus of any preceding clause, wherein the housing comprises a flange extending from the sidewall proximate a top of the sidewall.
300. The additive manufacturing apparatus of any preceding clause, wherein a seal is disposed between the build platform and an interior surface of the sidewall.
301. The additive manufacturing apparatus of any preceding clause, wherein the build platform comprises a seal seat in an edge of the build platform, the seal positioned in the seal seat such that the seal is disposed between the build platform and the interior surface of the sidewall.
302. The additive manufacturing apparatus of any preceding clause, wherein the build platform comprises a seal seat in an edge of the build platform, the seal positioned in the seal seat such that the seal is disposed between the build platform and the interior surface of the sidewall.
303. The additive manufacturing apparatus of any preceding clause, wherein the build platform is seated on the retention tabs when the build platform is in the lower position.
304. The additive manufacturing apparatus of any preceding clause, further comprising a second plurality of heating elements disposed on an exterior surface of the sidewall.
305. The additive manufacturing apparatus of any preceding clause, further comprising a plurality of sensors disposed throughout the plurality of heating elements.
306. The additive manufacturing apparatus of any preceding clause, wherein the plurality of heating elements are communicatively coupled to at least one electrical connector disposed on the exterior surface of the sidewall.
307. The additive manufacturing apparatus of any preceding clause, wherein the electrical connectors supply power to the heating elements and transmit electrical signals from the build receptacle indicative of a temperature of the sidewall of the build receptacle.
308. A method of building an object by additive manufacturing that may be used in conjunction with any of the methods, apparatuses, or assemblies of any preceding clause. The method includes pre-heating a deposition region of a build chamber to a pre-heat temperature, distributing a layer of build material on a build platform positioned within the build chamber, depositing a layer of binder material on the layer of build material, and adjusting a position of the build platform such that a portion of build material and binder is within a curing region of the build chamber. The curing region of the build chamber is below the deposition region of the build chamber. The method further includes heating the curing region of the build chamber to a curing temperature, wherein the curing temperature is greater than the pre-heat temperature. The method further includes curing the portion of binder within the lower portion of the build chamber, and distributing a new layer of build material above the portion of build material and binder on the build platform.
309. The method of any preceding clause, wherein the heating and pre-heating are achieved with a plurality of heating elements positioned around the build chamber.
310. The method of any preceding clause, wherein the heating and pre-heating are achieved with a plurality of heating elements positioned around the build chamber.
311. The method of any preceding clause, wherein the pre-heat temperature is from 25° C. to 130° C.
312. The method of any preceding clause, wherein the pre-heat temperature is less than or equal to 70° C.
313. The method of any preceding clause, the curing temperature is from 100° C. to 250° C.
314. The method of any preceding clause, wherein the curing temperature is from 100° C. to 250° C.
315. The method of any preceding clause, further comprising detecting a temperature of the curing region and adjusting the curing temperature based on the detected temperature of the curing region.
316. An additive manufacturing apparatus that may be used in conjunction with the apparatuses, assemblies and methods of any preceding clause. The additive manufacturing apparatus comprises: a support chassis comprising a print bay, a build bay, and a material supply bay, each bay comprising an upper compartment and a lower compartment; and a working surface separating each of the print bay, the build bay, and the material supply bay into the upper compartment and the lower compartment, wherein: the build bay is disposed between the print bay and the material supply bay; and the lower compartment of the build bay comprises bulkheads sealing the lower compartment of the build bay from the lower compartment of the print bay and the lower compartment of the material supply bay.
317. The additive manufacturing apparatus of any preceding clause, further comprising: a high voltage electrical supply cabinet; and a low voltage electrical supply cabinet, wherein the high voltage electrical supply cabinet is located at a first end of the support chassis and the low voltage supply cabinet is located at a second end of the support chassis opposite the first end.
318. The additive manufacturing apparatus of any preceding clause, wherein: the support chassis comprises a front and back; low voltage supply lines are directed through cable trays at the front or the back of the support chassis; and high voltage supply lines are directed through cable trays at the other of the front and back of the support chassis.
319. The additive manufacturing apparatus of any preceding clause, wherein the cable trays comprising low voltage supply lines further comprise at least on of air lines, vacuum lines, and liquid lines.
320. The additive manufacturing apparatus of any preceding clause, wherein the cable trays are positioned proximate a top of the support chassis, a bottom of the support chassis, or proximate both a top and bottom of the support chassis.
321. The additive manufacturing apparatus of any preceding clause, wherein the cable trays, low voltage supply lines, and high voltage supply lines extend through the lower compartment of the build bay and are sealed to the bulk heads of the build bay with sealing glands.
322. The additive manufacturing apparatus of any preceding clause, wherein: the print bay comprises a cleaning station; a cleaning solution supply tank is positioned in the lower compartment of the print bay and fluidly coupled to the cleaning station; and a binder supply tank positioned in the lower compartment of the print bay, wherein the binder supply tank is fluidly coupled to a print head of the additive manufacturing apparatus.
323. The additive manufacturing apparatus of any preceding clause, further comprising a cleaning solution recovery tank is positioned in the lower compartment of the print bay and fluidly coupled to the cleaning station.
324. The additive manufacturing apparatus of any preceding clause, wherein: the working surface in the build bay comprises an opening for removably receiving a build receptacle; and a lift system is positioned in the lower compartment of the build bay, the lift system for raising and lowering a build platform of the build receptacle when the build receptacle is positioned in the opening of the working surface of the build bay.
325. The additive manufacturing apparatus of any preceding clause, further comprising a build temperature sensor positioned in the build bay and oriented to detect a temperature of a surface of the build platform of the build receptacle when the build receptacle is positioned in the opening of the working surface of the build bay.
326. The additive manufacturing apparatus of any preceding clause, further comprising a build bay temperature sensor positioned in the lower compartment of the build bay, the build receptacle temperature sensor configured to detect a temperature of the lower compartment of the build bay.
327. The additive manufacturing apparatus of any preceding clause, further comprising a camera system oriented to capture images of a surface of the build platform of the build receptacle when the build receptacle is positioned in the opening of the working surface of the build bay.
328. The additive manufacturing apparatus of any preceding clause, further comprising an environmental sensor positioned within the build bay, the material supply bay, or the print bay, the environmental sensor configured to detect at least one of an air temperature within the support chassis and humidity within the support chassis.
329. The additive manufacturing apparatus of any preceding clause, wherein: the working surface in the material supply bay comprises an opening for receiving a supply receptacle; and a lift system is positioned in the lower compartment of the material supply bay, the lift system for raising and lowering a supply platform of the supply receptacle when the supply receptacle is positioned in the opening of the working surface of the material supply bay.
330. The additive manufacturing apparatus of any preceding clause, wherein the print bay, the build bay, and the material supply bay each comprise at least one access panel coupled to the lower compartment and at least one access panel coupled to the upper compartment.
331. The additive manufacturing apparatus of any preceding clause, further comprising: air inlets in the lower compartment of the build bay; and a lower exhaust system coupled to the lower compartment of the build bay, wherein air is drawn into the lower compartment of the build bay through the air inlets and exhausted out of the build bay with the lower exhaust system.
332. The additive manufacturing apparatus of any preceding clause, wherein the air inlets are positioned proximate a top of the lower compartment of the build bay and the lower exhaust system is coupled to the lower compartment of the build bay proximate a bottom of the lower compartment of the build bay.
333. The additive manufacturing apparatus of any preceding clause, wherein the lower exhaust system is coupled to a floor panel of the build bay.
334. The additive manufacturing apparatus of any preceding clause, wherein the lower exhaust system comprises a filter.
335. The additive manufacturing apparatus of any preceding clause, wherein: the support chassis comprises a top panel enclosing a top of the support chassis; and an upper exhaust system is coupled to the top panel.
336. The additive manufacturing apparatus of any preceding clause, wherein the upper exhaust system comprises a filter.
337. The additive manufacturing apparatus of any preceding clause, further comprising: a powder recovery slot extending through the working surface in one of the build bay and the material supply bay; a recovery funnel coupled to the powder recovery slot; and a vacuum system coupled to the recovery funnel, the vacuum system applying a negative pressure to the recovery funnel and the powder recovery slot.
338. The additive manufacturing apparatus of any preceding clause, wherein a sidewall of the powder recovery slot comprises a cone angle of less than or equal to 60 degrees with respect to a vertical axis.
339. The additive manufacturing apparatus of any preceding clause, wherein the vacuum system couples the powder recovery slot and recovery funnel to the sieve system.
340. The additive manufacturing apparatus of any preceding clause, further comprising: an actuator assembly comprising a recoat head, the recoat head comprising a containment housing; and a vacuum system coupled to the containment housing, whereby the vacuum system applies a negative pressure to the containment housing.
341. The additive manufacturing apparatus of any preceding clause, wherein the vacuum system couples the containment housing to the sieve system.
342. The additive manufacturing apparatus of any preceding clause, further comprising: an actuator assembly comprising a print head, the print head comprising a print head housing; and an air pump coupled to the print head housing, the air pump providing an overpressure to the print head housing.
343. An actuator assembly for distributing build material and depositing binder material in an additive manufacturing apparatus of any preceding clause comprises an upper support; a lower support spaced from the upper support in a vertical direction, the upper support and the lower support extending in a horizontal direction; a recoat head for distributing build material; a print head for depositing binder material; a recoat head actuator coupled to the recoat head and one of the upper support and the lower support, the recoat head actuator comprising a recoat motion axis, wherein the recoat head actuator is bi-directionally actuatable along the recoat motion axis thereby effecting bi-directional movement of the recoat head; a print head actuator coupled to the print head and the other of the upper support and the lower support, the print head actuator comprising a print motion axis, wherein the print head actuator is bi-directionally actuatable along the print motion axis thereby effecting bi-directional movement of the print head, wherein the recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in the vertical direction; and a control system communicatively coupled to the recoat head actuator and the print head actuator, the control system comprising a processor and a non-transitory memory storing computer readable and executable instructions that, when executed by the processor, cause: the recoat head actuator and the print head actuator to independently move the recoat head and the print head along a working axis during a build cycle, wherein, during the build cycle, the recoat head and the print head occupy an overlapping position on the working axis; and the processor to abort the build cycle in response to the processor determining that the print head and the recoat head are separated by less than a minimum separation distance.
344. The actuator assembly of any preceding clause, wherein the minimum separation distance is determined based on maximum velocities of the print head and the recoat head during the build cycle.
345. The actuator assembly of any preceding clause, wherein the processor calculates the minimum separation distance during the build cycle based on velocities of the print head and the recoat head during the build cycle.
346. The actuator assembly of any preceding clause, wherein the print head actuator comprises a first linear encoder and the recoat head actuator comprises a second linear encoder, wherein the processor determines that the print head and the recoat head are separated by less than the minimum separation distance based on measurements by the first and second linear encoders.
347. The actuator assembly of any preceding clause, further comprising a proximity sensor disposed on one of the print head and the recoat head, wherein the processor determines that the print head and the recoat head are separated by less than the minimum separation distance based on a signal generated by the proximity sensor.
348. An additive manufacturing apparatus of any preceding clause comprising: a cleaning station comprising a cleaning station cycle time; a build platform; a recoat head for distributing build material, the recoat head coupled to a recoat head actuator comprising a recoat motion axis, the recoat head and recoat head actuator comprising a recoat cycle time; a print head for depositing binder material, the print head coupled to a print head actuator comprising a print motion axis, the print head and the print head actuator comprising a print cycle time; and a control system is communicatively coupled to the recoat head actuator and the print head actuator, the control system configured to cause independent motion of the print head and the recoat head during a build cycle, the build cycle having an overall build cycle time that is less than the sum of cleaning station cycle time, the recoat cycle time, and the print cycle time, wherein, during the build cycle time, the control system is configured to abort the build cycle in response to determining that the print head and the recoat head are separated by less than a minimum separation distance.
349. The additive manufacturing apparatus of any preceding clause, wherein the minimum separation distance is determined based on maximum velocities of the print head and the recoat head during the build cycle.
350. The additive manufacturing apparatus of any preceding clause, wherein the control system calculates the minimum separation distance during the build cycle based on velocities of the print head and the recoat head.
351. A method of building an object by additive manufacturing of any preceding clause, the method comprising: distributing a new layer of build material on a build platform with a recoat head coupled to a recoat head actuator, the recoat head actuator comprising a recoat motion axis whereby actuation of the recoat head actuator along the recoat motion axis in a first recoat direction causes the recoat head to distribute the new layer of build material on the build platform; and depositing a binder material on the new layer of build material with a print head coupled to a print head actuator, the print head actuator comprising a print motion axis whereby the binder material is deposited with the print head by actuating the print head actuator along the print motion axis in a first print direction opposite the first recoat direction, wherein a timing of the actuating the print head actuator along the print motion axis in the first print direction is determined based on a minimum separation between the print coat head and the recoat head.
352. The method of any preceding clause, further comprising determining that the print head and the recoat head are separated by less than the minimum separation distance; and responsive to the determination, returning the print head to a print home position and the recoat head to a recoat home position.
353. The method of any preceding clause, wherein determining that the print head and the recoat head are separated by less than the minimum separation distance comprises determining a position of the print head along the print motion axis and a position of the recoat head along the recoat motion axis using linear encoders of the print head actuator and the recoat head actuator, respectively.
354. The method of any preceding clause, wherein determining that the print head and the recoat head are separated by less than the minimum separation distance comprises measuring a proximity of the print head to the recoat head via a proximity sensor disposed on the print head or the recoat head.
355. The method of any preceding clause, further comprising calculating the minimum separation distance prior to distributing the new layer of build material or depositing the binder material by determining a maximum relative velocity at which the print head and the recoat head are moved towards each other during the distribution of the new layer of build material and the deposition of the binder material.
356. The method of any preceding clause, further comprising calculating the minimum separation distance during the distribution of the new layer of build material and the deposition of the binder material based on rates at which the print head and the recoat head are actuated.
357. A method of building an object by additive manufacturing of any preceding clause, the method comprising: pre-heating a deposition region of a build chamber to a pre-heat temperature; distributing a layer of build material on a build platform positioned within the build chamber with a recoat assembly moving in a coating direction; depositing a layer of binder material on the layer of build material; irradiating the layer of build material with an energy source coupled to the recoat assembly; adjusting a position of the build platform such that a portion of build material and binder is within a curing region of the build chamber, wherein the curing region of the build chamber is below the deposition region of the build chamber; heating the curing region of the build chamber to a curing temperature, wherein the curing temperature is greater than the pre-heat temperature; curing the binder within the curing region of the build chamber; and distributing a new layer of build material above the portion of build material and binder on the build platform.
358. The method of any preceding clause, wherein the layer of build material is irradiated with the energy source coupled to the recoat assembly before depositing the layer of binder material on the layer of build material.
359. The method of any preceding clause, wherein the layer of build material is irradiated with the energy source coupled to the recoat assembly after depositing the layer of binder material on the layer of build material.
360. The method of any preceding clause, wherein the layer of build material is irradiated with the energy source coupled to the recoat assembly both before and after depositing the layer of binder material on the layer of build material.
361. The method of any preceding clause, wherein the heating and pre-heating are achieved with a plurality of heating elements positioned around the build chamber, below the build platform or both around the build chamber and below the build platform.
362. A method of building an object by additive manufacturing of any preceding clause, the method comprising: moving a recoat assembly over a build material with a recoat head actuator, the recoat head actuator comprising a recoat motion axis, whereby actuation of the recoat head actuator along the recoat motion axis in a first recoat direction causes the recoat assembly to move in the first recoat direction, and wherein the recoat assembly comprises a first roller and a second roller that is spaced apart from the first roller; rotating the first roller of the recoat assembly in a counter-rotation direction, such that a bottom of the first roller moves in the first recoat direction; contacting the build material with the first roller of the recoat assembly, thereby fluidizing at least a portion of the build material; irradiating, with a front energy source coupled to a front end of the recoat assembly, an initial layer of build material positioned in a build area; subsequent to irradiating the initial layer of build material, spreading the build material on the build area with the first roller, thereby depositing a second layer of the build material over the initial layer of build material; subsequent to spreading the second layer of the build material, irradiating, with a rear energy source positioned rearward of the front energy source, the second layer of build material within the build area; and depositing a binder material on the second layer of build material with a print head coupled to a print head actuator, the print head actuator comprising a print motion axis whereby the binder material is deposited with the print head by actuating the print head actuator along the print motion axis in a first print direction opposite the first recoat direction, wherein the recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in a vertical direction.
363. The method of any preceding clause, wherein a timing of the actuating the print head actuator along the print motion axis in the first print direction is determined based on a minimum separation between the print coat head and the recoat assembly.
364. The method of any preceding clause, further comprising, subsequent to at least one of irradiating the initial layer of build material with the front energy source and irradiating the second layer of build material with the rear energy source, detecting a temperature of the irradiated build material with a temperature sensor.
365. The method of any preceding clause, further comprising changing at least one parameter of the front energy source or the rear energy source based at least in part on the detected temperature.
366. The method of any preceding clause, further comprising engaging a cleaning member with at least one of the first roller and the second roller.
367. A method for forming an object with an additive manufacturing system of any preceding clause comprising a supply platform, a cleaning station, and a build area horizontally positioned between the cleaning station and the supply platform, wherein the cleaning station comprises a binder purge bin and a cleaning station vessel having cleaning fluid therein and comprising a wet wipe cleaner section, and a dry wipe cleaner section, the method comprising: distributing a new layer of build material on the build area with a recoat assembly coupled to a recoat head actuator, the recoat head actuator comprising a recoat motion axis whereby actuation of the recoat head actuator along the recoat motion axis in a first recoat direction causes the recoat assembly to distribute the new layer of build material on the build area; depositing a binder material on the new layer of build material with a print head coupled to a print head actuator, the print head actuator comprising a print head motion axis whereby the binder material is deposited with the print head by actuating the print head actuator along the print head motion axis in a first print direction opposite the first recoat direction, where the recoat motion axis and the print head motion axis are parallel to one another and spaced apart from one another in a vertical direction; passing the print head over the binder purge bin to facilitate discharge of contaminants from the print head via backpressure; introducing the print head to the wet wipe cleaner section so that cleaning fluid is applied to the print head by a wet wipe member; and introducing the print head to the dry wipe cleaner section so that cleaning fluid is removed by a dry wipe member and the print head is thereby cleaned.
368. The method of any preceding clause, wherein the dry wipe member is vertically raised out of the cleaning fluid before completion of discharge of contaminants from the print head.
369. The method of any preceding clause, wherein the wet wipe member is vertically raised out of the out of the cleaning fluid when discharge of contaminants from the print head is complete.
370. The method of any preceding clause, wherein binder material is discharged into the binder purge bin while a recoat head is operating in a direction supplying build material to a working surface of the build platform.
371. The method of any preceding clause, wherein prior to passing the print head over the binder purge bin, introducing the print head to at least one of the dry wipe cleaner section and the wet wipe cleaner section to pre-clean the print head.
372. A method of building an object by additive manufacturing of any preceding claim, the method comprising: distributing a layer of build material on a build platform with a recoat head that is coupled to a recoat head actuator configured to move the recoat head along a longitudinal axis during distribution of the layer of build material; depositing binder through select ones of a plurality of jet nozzles of a printing head onto the layer of build material as the printing head traverses a first pass trajectory along a longitudinal axis in a first direction; indexing the printing head along a latitudinal axis to a second pass trajectory by an index distance; depositing binder through select ones of the plurality of jet nozzles of the printing head as the printing head traverses the second pass trajectory along a longitudinal axis in a second direction opposite the first direction; and distributing a new layer of build material above the layer of build material and binder on the build platform.
373. The method of any preceding clause, wherein: a distance from a first jet nozzle to a second jet nozzle positioned adjacent the first jet nozzle of the plurality of jet nozzles defines a jet-spacing, and the index distance is greater than zero and less than the jet-spacing.
374. The method of any preceding clause, wherein: a distance from a first jet nozzle to a second jet nozzle positioned adjacent the first jet nozzle of the plurality of jet nozzles defines a jet-spacing, and the index distance is an integer multiple of a fractional value of the jet-spacing.
375. The method of any preceding clause, wherein: a distance from a first jet nozzle to a second jet nozzle positioned adjacent the first jet nozzle of the plurality of jet nozzles defines a jet-spacing, and the index distance is an integer multiple of the jet-spacing.
376. The method of any preceding clause, wherein the printing head comprises a first print head row comprising a plurality of print heads sequentially spaced apart from one another in a direction transverse to a working axis, an actuator is coupled to a first print head of the plurality of print heads, and the actuator is configured to move the first print head along the latitudinal axis.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.
The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/851,919 filed May 23, 2019, and entitled “Additive Manufacturing Apparatuses and Methods,” U.S. Provisional Patent Application Ser. No. 62/852,034 filed May 23, 2019, and entitled “Cleaning Systems for Additive Manufacturing Apparatuses and Methods for Using the Same,” U.S. Provisional Patent Application Ser. No. 62/852,030 filed May 23, 2019, and entitled “Cleaning Fluids for Use in Additive Manufacturing Apparatuses and Methods for Monitoring Status and Performance of the Same,” U.S. Provisional Patent Application Ser. No. 62/851,913 filed May 23, 2019, and entitled “Build Receptacles for Additive Manufacturing Apparatuses and Methods for Using the Same,” U.S. Provisional Patent Application Ser. No. 62/851,907 filed May 23, 2019, and entitled “Actuator Assemblies for Additive Manufacturing Apparatuses and Methods for Using the Same,” U.S. Provisional Patent Application Ser. No. 62/851,953 filed May 23, 2019, and entitled “Additive Manufacturing Recoat Assemblies Including Sensors and Methods for Using the Same,” U.S. Provisional Patent Application Ser. No. 62/851,957 filed May 23, 2019, and entitled “Printing Assemblies and Methods for Using the Same,” and U.S. Provisional Patent Application Ser. No. 62/851,946 filed May 23, 2019, and entitled “Additive Manufacturing Apparatuses and Methods for Using the Same,” the entirety of each of which is incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/034244 | 5/22/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62852034 | May 2019 | US | |
| 62852030 | May 2019 | US | |
| 62851913 | May 2019 | US | |
| 62851907 | May 2019 | US | |
| 62851953 | May 2019 | US | |
| 62851957 | May 2019 | US | |
| 62851919 | May 2019 | US | |
| 62851946 | May 2019 | US |
