Patent Application
20210260819
This application may contain material that is subject to copyright, mask work, and/or other intellectual property protection. The respective owners of such intellectual property have no objection to the facsimile reproduction of the disclosure by anyone as it appears in published Patent Office file/records, but otherwise reserve all rights.
Furthermore, the present disclosure relates to systems, apparatuses, and methods for additive manufacturing or printing of three dimensional (3D) objects, and more specifically, to additive manufacturing or 3D printing (3DP) having an interface fluid.
Some types of manufacturing create physical objects by laying down or building up many thin layers of material in succession, this is sometimes referred to as “3D Printing.” A 3D printer can include a container for holding a liquid polymer that can be cured to produce a 3D object. The printer can include a light source and a controller that selectively controls the light source to expose the liquid polymer to light print the successive layers of the 3D object.
While existing 3D printers are suitable for their intended purposes the need for improvement remains, particularly in providing a 3D printing device having the features described herein.
According to one aspect of the disclosure a method is provided. The method including flowing an interface fluid into a vessel, the interface fluid having a first density. A photopolymer is flowed into the vessel, the photopolymer having a second density, the second density being less than the first density. A build plate is disposed within the photopolymer, the build plate being positioned a predetermined layer thickness from an interface of the photopolymer and interface fluid. At least a portion of the photopolymer is irradiated with a light source to define a first layer of an object being fabricated, the portion of the polymer being disposed between the interface fluid and the build plate. The build plate is moved in a direction away from the interface fluid a predetermined second distance.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include repeating the steps to define a second layer of the object being fabricated. In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include directing the flow of photopolymer upwards as the photopolymer enters the vessel and prior to contact with the interface fluid. In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include the interface fluid being saline.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include forming a meniscus with the interface fluid near the edge of the vessel, wherein the portion of the photopolymer is spaced apart from the meniscus. In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include flowing photopolymer into a space between the first layer and the interface fluid in response to moving the build plate. In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include continuously moving the build plate while the light source continuously and dynamically irradiates the photopolymer. In addition to one or more of the features described herein, or as an alternative, further embodiments of the method may include continuously separating the cured photopolymer from the interface fluid as the build plate is moved.
In accordance with another aspect of the disclosure, a system for forming an object through additive manufacturing is provided. The system including a vessel having a bottom side and an interface fluid disposed within the vessel. A photopolymer is disposed within the vessel and in contact with the interface fluid. A build plate is disposed within the photopolymer and spaced apart from the interface fluid, the build plate being movable from a first position to a second position. A light source is positioned to direct electromagnetic radiation into the build plate.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include the interface fluid being saline. In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include the vessel including at least one first structural feature configured to flow interface fluid into the vessel. In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include the vessel including at least one second structural feature configured to flow photopolymer into the vessel. In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include the second structural feature including a lip configured to direct photopolymer upwards as the photopolymer enters the interior of the vessel.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include one or more processors configured to continuously move the build plate as the light source continuously and dynamically irradiates the photopolymer in a predetermined pattern. In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include the vessel including an optically clear window between the interface fluid and the light source. In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include a linear drive mechanism operably coupled to the build plate, the linear drive mechanism being configured to move the build plate between the first position and the second position.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include a build arm coupled between the linear drive mechanism and the build plate. In addition to one or more of the features described herein, or as an alternative, further embodiments of the system may include a pump operably coupled to flow interface fluid into the vessel.
An understanding of the features of the disclosure herein may be had by reference to the appended drawings, which illustrate the method and system of the disclosure, although it will be understood that such drawings depict preferred embodiments of the disclosure and, therefore, are not to be considered as limiting its scope with regard to other embodiments which the disclosure is capable of contemplating. Furthermore, elements or components that are described with reference to any one figure may be interchanged with those of other figures without departing from the scope of the present teaching.
Processes and devices described herein relate to additive manufacturing, also referred to as 3D printing. Such processes and devices can provide an alternative to standard release mechanisms of the additive process of forming objects by curing a photopolymer one layer after another against a vessel floor. In some embodiments, a process and apparatus for additive manufacturing uses an interface fluid placed against (e.g., in contact with) the photopolymer to allow for destruction free “separation” of cured polymer from the interface fluid in an oxygen free environment. The process incorporates the use of a vessel, which contains the interface fluid and photopolymer together. The process also comprises the use of a build plate and light source contained within a 3D printing device.
The descriptions herein refer to additive manufacturing processes and apparatus as well as to device(s) that utilize said processes and apparatus. Processes described herein can enable commercialization of low cost, fast additive manufacturing equipment. These processes can be different from currently available processes that use a different method of releasing a photopolymer, which usually occurs after curing any given layer. In embodiments described herein, a process referred to as the Solid-Liquid Interface Curing (SLIC) process, uses an interface liquid barrier between a light source and a photopolymer, e.g., to create a vacuum free cure zone. A lack of vacuum force/low pressure (or any other non-negligible force) between the solid cured photopolymer and liquid interface allows the build plate to move continuously (e.g., without turning off the light source and/or moving back-and-forth to separate cured polymer from the interface) during printing and it also achieves continuous non-destructive release, post curing of the photopolymer. With the SLIC process, the curing process does not require stopping to enable release of the photopolymer as when the photopolymer shrinks, rather than a low-pressure region being formed, the high density fluid maintains contact with the cured photopolymer.
Certain methods or processes for additive manufacturing of photopolymer materials may use a separation method (e.g., release mechanism) that requires stopping the curing process during the printing process. Processes and devices described herein do not require the build plate to stop or reverse direction, which can have significant time savings throughout the printing process. For example, such processes and devices do not require the build plate to lift, stop and then drop on each layer of photopolymer. Additionally, these processes do not require a light source to be disabled for a period of time to allow the release mechanism to complete, again having considerable time savings throughout the duration of the printing process.
Systems, apparatus, and methods are described for providing an additive manufacturing process involving continuously curing photopolymers using a vessel containing an interface fluid. In some embodiments, an apparatus includes a vessel designed to contain a photopolymer as well as an optically and UV transmissive fluid that is denser than the photopolymer. The use of the denser fluid can prevent printed part quality issues caused by printing at an open surface (e.g., an exposed surface) of the fluid photopolymer and/or increase print speed by eliminating a separation step that is common in the operation of some 3D printers. Due to the viscosity and surface tension present in many photopolymers, issues such as delamination and warping can occur when printing at the open surface of the photopolymer. Significant time and/or hardware can be required to avoid these problems. It is therefore advantageous to print/cure at and/or along an interface of a fluid, which is greater in density than that of air. Systems, apparatus, and methods described herein can provide a light source placed below the vessel containing a relatively higher density fluid. In some embodiments, the light source can be placed on the underside of the photopolymer. Alternatively, to enable curing of the photopolymer at an interface of an optically clear fluid (e.g., a liquid) having density greater than that of air but less than the photopolymer such that the photopolymer rests below the optically clear fluid, the light source can be provided at other locations (e.g., above the vessel). The process of curing associated with such systems, apparatus, and methods is referred to herein as Solid-Liquid Interface Curing (SLIC).
3D manufacturing or additive manufacturing devices and methods may use computer controlled light engines to dynamically direct light at certain portions of a photopolymer. A vessel containing a photopolymer can form a part of the 3D manufacturing device. Objects manufactured using a 3D manufacturing device are typically cured within a vessel against an optically clear window to avoid the aforementioned issues with printing at an open surface of the photopolymer. Once cured, a force exists that can hold the cured layer against the window. This force can be, for example, primarily comprised of a vacuum force (low pressure zone) created by the photopolymer shrinking and van der Waals forces to lesser extent. This force is overcome in order to move (e.g., raise) the print bed into position for curing the next layer of photopolymer. The mechanism and/or method used to overcome this force can be referred to as a release mechanism herein. The objective of the release mechanism is to be gentle and fast so as to not damage the cured layer but optimise the print speed. Devices and methods described herein do not require an optically clear window to cure against and thus have no requirement for a release mechanism, while also preventing the problems associated with printing at an open surface of a photopolymer.
The additive manufacturing and printing processes described herein provide several advantages over other 3D printing methods, including, for example, higher manufacturing speeds and lower cost, because such systems and methods do not require a release mechanism and/or do not require the printing process to stop to perform the release mechanism.
A device according to the present disclosure can include a 3D printer and a vessel that contains a volume of a photopolymer and a volume of optically clear and UV transmissive interface fluid. In addition to these components, the device can also include one or more of: a build plate that can be held parallel to an opening of the vessel (e.g., a print bed or surface upon which an object can be printed) and a build arm attached to a build plate (e.g., print bed) which attaches to the printer once installed.
In an embodiment, the vessel can contain a photopolymer that can float upon (e.g., be disposed above) a higher density optically clear fluid. An example of a higher density optically clear fluid is saline. The fluid can act as an interface between a light source (e.g., being used to cure the photopolymer) and the cured photopolymer. The higher density optically clear fluid being between the light source and the photopolymer can reduce a low pressure force created due to the photopolymer shrinking when being cured as well as any other forces which would otherwise act to keep the cured photopolymer against a solid substrate. During operation, the electromagnetic radiation from the light source passes through the bottom side of the vessel, which is optically clear and UV transmissive in the desired wavelength. An example of a suitable material for the vessel bottom is acrylic. The light then passes through the higher density fluid and subsequently cures a photopolymer, in a desired pattern, that is one “layer height” thick at a start of the printing process. The photopolymer can be one layer height thick because a print bed can be placed in a position that is one layer height away from the higher density optically clear fluid at the start of the printing process, such that the cured photopolymer (e.g., resin) adheres to the print bed surface, and can be moved, e.g., in a controlled and automated fashion, enabling curing (e.g., continuous curing) without requiring a separation or release mechanism step (e.g., to release or separate cured photopolymer from a print head) to be performed before emitting light from the light source to cure the next layer of photopolymer. Stated differently, systems, apparatus, and methods disclosed herein can provide a device that can cause photo initiators in a photopolymer composition to become photoinitiated and harden the polymer in a controlled way, continuously, e.g., without stopping to perform a release mechanism step.
The vessel design can be such that it can be mounted inside of a 3D printer, and the light source may be placed above or below the vessel, and the print bed can enter the vessel through a top side via an opening. Movement of the print bed is performed in a controlled and automated fashion along a single vertical axis (e.g., z axis) of motion. The vessel utilised with a digital light source (e.g., such as a Digital Light Projection (“DLP”) system) and print bed contained within a 3D printer device, which are each described herein, is capable of curing photopolymer continuously throughout the printing process by controlling the specific point (e.g., portion) in the photopolymer that is exposed to electromagnetic radiation without having to stop to perform “separation” (e.g., release or separation of a cured layer from a printer component).
In some embodiments, the devices described herein can be used with methods such as SLIC, as described herein. The devices, described in relation to SLIC, have particular applications, for example, in the Industrial production of parts or objects as well as rapid prototyping, e.g., in automotive manufacturing, product design or consumer applications, where speed and cost are important. The disclosed devices also have applicability in Science, Technology, Engineering, the Arts and Mathematics (STEAM) applications and other educational applications, including educational programs.
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To manufacture any given object (e.g., 3D model), the build plate 108 is lowered into the vessel 103 such that a bottom surface of the build plate is 1-layer height above the top surface of the interface fluid 105. In some embodiments, the volume of the interface fluid can be adjusted. Such volume adjustments can be accomplished via an on-board (e.g., contained within the system 100) processor 115 that can control a fluid pump 116, e.g., in an automated fashion. The build plate 108 can be attached to a build arm 111, which in turn can be attached to other portions of the system 100.
When in its initial starting position, e.g., as illustrated in
Continuous cycle time=Cure Time+Time to move build plate 108 to a position 1−layer height from its previous position
As opposed to:
Non-continuous cycle time=Cure Time+Time to lift some distance away(Separation time)+Time to move print bed to a position 1−layer height from its previous position
Eliminating the additional separation time has time saving advantages, e.g., when there may be thousands or tens of thousands of layers in a single print, and the separation times being tens of seconds or more depending on the technique and process used.
Devices described herein, such as example systems and devices set forth in
As shown in
The system 100 is capable of moving the build plate 108 along an axis (e.g., along a direction indicated by arrow/axis 109). The system 100 may also contain subcomponents that may or may not be necessary for the operation of the end SLIC—Vessel 103, such as, for example, fluid pumping apparatus 116 and associated electronics 115. It should be noted that the photopolymer 106 has a natural resting thickness. The layer of photopolymer supported by the relatively higher density interface fluid may be thicker than the natural resting thickness. This resting thickness is a result of the materials characteristics such as viscosity which can be affected by variables such as temperature. Therefore, a desired condition of variables exists for a particular photopolymer 106 and it can be understood that these variables are controllable through additional printer components such as heating elements (not shown).
Certain technical advantages associated with the continuous curing of a photopolymer during a printing process, to which the processes and system described herein refer (e.g., the assembly and/or methods of the present embodiments, including SLIC and SLIC—Vessel), include but are not limited to: the reduction of forces between the printed object and the interface material allowing for gentler separation (e.g., less force to be overcome for separation) and thus less risk of damage to the cured photopolymer or printer; the continuous separation of cured photopolymer does not impede or stop the curing/printing process. For example, the light source does not have to turn off in order to complete the separation of cured photopolymer allowing for faster 3D printing; issues associated with printing at the open surface are mitigated by printing in a submerged fashion; and the high density fluid may act like a lens, having a higher refractive index than that of air (by design), allowing relatively finer details to be resolved by the image source.
In operation, a user can plug in (e.g., connect a power source to) a manufacturing device (e.g., the 3D printing system shown in
The user can select various settings relative to the particular print and photopolymer in use. The user can start the print via an interaction of software and hardware (e.g., via a user interface, such as visual and/or audio user interface) which can be, for example, described in an operating manual. Once the print has begun, the printer dynamically moves the print bed as needed in a pre-determined fashion. Once a “layer” of the path (e.g., a layer of the print) has been completed, the build plate is moved upwards (e.g., away from the interface material) at a rate defined previously. While the build plate is moving upward, the light source is emitting the desired pattern for the build plate's current height (e.g., current layer) such that the light cures the photopolymer in the desired pattern. The rate of motion of the build plate is pre-determined such that the light source may have sufficient time to cure a layer pattern. This process continues until the desired object is built up.
While various embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto; embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.
Various methods and/or processes outlined herein can be coded as software that is executable on one or more processors that employ any one of a variety of operating systems or platforms. Additionally, such software can be written using any of a number of suitable programming languages and/or programming or scripting tools, and also can be compiled as executable machine language code or intermediate code that is executed on a framework or virtual machine.
In this respect, various disclosed concepts can be embodied as a non-transitory computer readable storage medium (or multiple computer readable storage media) (e.g., a computer memory, one or more floppy discs, compact discs, optical discs, magnetic tapes, flash memories, circuit configurations in Field Programmable Gate Arrays or other semiconductor devices, or other non-transitory medium or tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods that implement the various embodiments of the disclosure discussed above. The computer readable medium or media can be transportable, such that the program or programs stored thereon can be loaded onto one or more different computers/compute device and/or other processors to implement various aspects of the present disclosure as discussed above.
The terms “program” or “software” are used herein in a general sense to refer to any type of computer code or set of computer-executable instructions that can be employed to program a computer or other processor to implement various aspects of embodiments as discussed above. Additionally, it should be appreciated that according to one aspect, one or more computer programs that when executed perform methods of the present disclosure can be distributed in a modular fashion amongst a number of different compute devices/processors to implement various aspects of the disclosure.
Processor-executable instructions can be in many forms, such as program modules, executed by one or more compute devices, and can include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular data types, and the functionality can be combined and/or distributed as appropriate for various embodiments.
Data structures can be stored in processor-readable media in a number of suitable forms. For simplicity of illustration, data structures may be shown to have fields that are related through location in the data structure. Such relationships can likewise be achieved by assigning storage for the fields with locations in a processor-readable medium that conveys relationship(s) between the fields. However, any suitable mechanism/tool can be used to establish a relationship between information in fields of a data structure, including through the use of pointers, tags or other mechanisms/tools that establish relationship between data elements.
Also, various concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.
| Number | Date | Country | |
|---|---|---|---|
| 62979758 | Feb 2020 | US |
