Patent Application
20160193787
The present invention concerns a manufacturing system and equipment assembly and use thereof for the preparation three-dimensional printing of articles from one or more powders and one or more liquids applied to the powder.
Rapid prototyping describes various techniques for fabricating a three-dimensional prototype of an object from a computer model of the object. One technique is three-dimensional printing, whereby a printer is used to fabricate the 3-D prototype from a plurality of two-dimensional layers. In particular, a digital representation of a 3-D object is stored in a computer memory. Computer software sections the representation of the object into a plurality of distinct 2-D layers. Alternatively, a stream (sequential series) of instructions for each incremental layer maybe entered directly, e.g. a series of images. A 3-D printer then fabricates a thin layer of bound material for each 2-D image layer sectioned by the software. Together, the layers are printed one on top of the other and adhere to each other to form the desired prototype.
Three-dimensional powder-liquid printing technology has been used to prepare articles such as pharmaceutical dosage forms, mechanical prototypes and concept models, molds for casting mechanical parts, bone growth promoting implants, electronic circuit boards, scaffolds for tissue engineering, responsive biomedical composites, tissue growth promoting implants, dental restorations, jewelry, fluid filters and other such articles.
Three-dimensional printing is a solid freeform fabrication technique/rapid-prototyping technique in which thin layers of powder are spread onto a surface and selected regions of the powder are bound together by the controlled deposition (“printing”) of a fluid. This basic operation is repeated layer-by-layer, with each new layer formed on top of and adhered to the previously printed layer, to eventually make three-dimensional objects within a bed of unbound powder. When the printed objects have sufficient cohesion, they may be separated from the unbound powder.
Systems and equipment assemblies for three-dimensional printing of articles are commercially available or in use by others: Massachusetts Institute of Technology Three-Dimensional Printing Laboratory (Cambridge, Mass.), Z Corporation's 3DP and HD3DP™ systems (Burlington, Mass.), The Ex One Company, L.L.C. (Irwin, Pa.), Soligen (Northridge, Calif.), Specific Surface Corporation (Franklin, Mass.), TDK Corporation (Chiba-ken, Japan), Therics L.L.C. (Akron, Ohio, now a part of Integra Lifesciences), Phoenix Analysis & Design Technologies (Tempe, Ariz.), Stratasys, Inc.'s Dimension™ system (Eden Prairie, Minn.), Objet Geometries (Billerica, Mass. or Rehovot, Israel), Xpress3D (Minneapolis, Minn.), and 3D Systems' Invision™ system (Valencia, Calif.).
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Three-dimensional printing systems that employ radial or polar coordinate-based printing systems are disadvantageous because having each jetting position located at a different radial position requires that the surface speed of the substrate underneath the each jetting position will vary. The surface speed will be greatest for the jetting position furthest from the center of rotation. This can be compensated for by normalizing the print density across all jetting positions by either adjusting the input images or possibly the drive frequency. However, these methods of compensation simply cause objects printed radially to emulate each other as opposed to true replicates. The angle of entry of the droplets into the powder bed will also vary with radial position again creating subtle differences in the objects printed at different locations. Alignment and interleaving of multiple print heads is another disadvantage to radially printing. Although feasible it is more complex than for Cartesian systems.
The present invention provides a manufacturing system and equipment assembly useful for the preparation of articles by three-dimensional printing. The system and assembly can be used for high through-put continuous, semi-continuous, or batch manufacture with minimal product loss, high efficiency, and high product reproducibility in the context of flexible article design.
The invention provides a three-dimensional printing equipment assembly comprising:
In some embodiments, the three-dimensional printing equipment assembly further comprises at least one liquid removal system adapted to receive one or more three-dimensionally printed beds and to remove liquid from one or more powder layers onto which the liquid has been applied and/or from the three-dimensionally printed bed.
In some embodiments, a build module comprises an incrementally height adjustable platform adapted to receive and temporarily retain at least one incremental layer or plural stacked incremental layers of powder. In some embodiments, a build module comprises a body comprising an upper surface with a cavity, a height adjustable build platform disposed within the cavity, height adjuster engaged with the body and the platform, and engagement means. In some embodiments, plural build modules are removably engaged with the conveyor system. In some embodiments, the platform is adapted to lower (recess) and/or raise by one or more increments after placement of an incremental layer of powder thereon. The platform displacement can occur prior to or after placement of a subsequent incremental layer of powder thereon, thereby press-rolling or removing a portion of powder from a powder layer that has already been laid down. In some embodiments, the size of an increment is predetermined. In some embodiments, the build module comprises one or more sidewalls surrounding the build plate and being adapted to retain powder on the height adjustable platform. In some embodiments, the build module further comprises a removable build plate disposed below the upper surface of the build module. In some embodiments, the removable build plate is disposed above the height adjustable platform and is adapted to receive and support one or more incremental layers of powder. In some embodiments, the removable build plate is flat, porous, perforated, textured, coated, knurled, smooth or a combination thereof. In some embodiments, engagement means are adapted to removably engage a build module with the conveyor system.
In some embodiments, the conveyor system conducts the plural build modules along a planar circuitous path, a horizontal circuitous path, a vertical circuitous path, or a combination thereof. In some embodiments, the conveyor system is adapted to transport plural build modules along a path in a counterclockwise direction or clockwise direction. In some embodiments, the path of the modular conveyor system is circular, ellipsoidal, rectangular, semicircular, square, triangular, pentagonal, hexagonal, octagon, oval, polygonal, parallelogram, quadrilateral, geometric, symmetrical, asymmetrical, or equivalents thereof with rounded corners and/or edges. In some embodiments, the modular conveyor system comprises plural conveyor modules, at least one drive motor, at least one positioning controller, and a path along which plural build modules are conducted. In some embodiments, a conveyor module comprises a body, one or more build module engagement means, and conveyor module engagement means by way of which plural conveyor modules are adapted to engage to form a modular conveyor. In some embodiments, the conveyor system comprises plural attachments adapted to removably retain the plural build modules. In some embodiments, the attachment comprises plural one or more metal links with cam followers or comprises wheels, plates and/or bearings attached to a build module and mounted on a rail system upon which the build module is conducted. In some embodiments, the conveyor system further comprises one or more positioning-controllers. In some embodiments, the conveyor system is a continuous or discontinuous loop system.
In some embodiments, the at least one build station is incrementally height adjustable with respect to the build modules, whereby the vertical space between the build module and the build station can be adjusted by one or more increments. In some embodiments, an incrementally height adjustable build station is adapted to raise by one or more increments after placement of a layer of powder on a build module and prior to placement of a subsequent layer of powder the build module. In some embodiments, a change in height is achieved by changing vertical position with respect to a prior position of the platform or with respect to an absolute position of the platform relative to the build module. In some embodiments, the build station is vertically fixed with respect to the build modules and a build platform within a build module is vertically height adjustable with respect to the build module so that the vertical distance between the build station and the build module remains the same during a print lap or print cycle.
In some embodiments, the size of the increment is the same for each incremental layer of a build cycle, is different for one or more incremental layers of a build cycle or a combination thereof. A build cycle comprises one or more build laps or plural build laps and is defined as the sum total of build laps required to form a 3DP article. A build lap is defined as the process of forming a printed incremental layer, i.e. placing an incremental layer of powdered build material and depositing (printing) liquid upon it. Accordingly, a build cycle results in the formation of plural stacked printed incremental layers that adhere to one another to together form a three-dimensionally printed article.
In some embodiments, the at least one powder layering system comprises at least one powder fill head. In some the embodiments, the powder fill head is stationary, meaning it does not move, either longitudinally or transversely with respect to the plane of the upper surface of a build module, when applying an incremental layer of powder onto the build module. In some embodiments, a powder fill head comprises at least one powder fill head body, at least one powder spreader, and at least one powder-height controller. In some embodiments, a powder layering system comprises a powder fill head, at least one powder reservoir and a powder feeder tube adapted to transfer powder from the powder reservoir to the powder fill head. In some embodiments, the powder spreader is a cylindrical roller the axis of which has or defines a radial direction of motion opposite the linear direction of motion of a build module through the powder layering system. In some embodiments, the powder spreader is a cylindrical roller, bar, rod, plate or straight smooth edge. In some embodiments, the powder fill head comprises a hopper or chute.
In some embodiments, the at least one printing system is adapted to apply (deposit) liquid to the powder according to a Cartesian coordinate algorithm instead of a polar (radial) coordinate algorithm (cylindrical coordinate system, circular coordinate system, or spherical coordinate system). In some embodiments, the printing system comprises at least one print head adapted to deposit liquid onto an incremental layer of powder in a build station and at least one liquid feed system. A print head can comprise one or more print modules or plural print modules. In some embodiments, the invention excludes a printing system adapted to apply liquid to the powder solely according to a polar (radial) coordinate system. In some embodiments, the invention excludes an equipment assembly or a method wherein the powder fill head moves laterally or transversely or is not stationary, with respect to a build module, while depositing an incremental powder layer. In some embodiments, the invention excludes an equipment assembly or a method wherein the print head moves laterally or transversely or is not stationary, with respect to a build module, while applying liquid to an incremental powder layer.
In some embodiments, the at least one printing system is adapted to apply (deposit) liquid as a three-dimensional pattern of droplets or as plural two-dimensional patterns of droplets defining one or more articles. In some embodiments, the pattern comprises droplets placed at equal spacing within one or more articles. In some embodiments, this pattern comprises droplets placed at unequal spacing within one or more articles. In some embodiments, this pattern comprises droplets with different spacing within different regions of an article. In some embodiments, this pattern comprises droplets with tighter spacing (i.e., higher print density) in a region defining the exterior of an article. In some embodiments, this pattern comprises droplets with looser spacing (i.e., lower print density) in a region interior to an article.
In some embodiments, more than one pattern is used. In some embodiments, more than one liquid is used. In some embodiments, the liquid comprises a pure solvent, blend of solvents, solution, suspension, colloid, emulsion, melt or a combination thereof.
In some embodiments, both the print head and the powder fill head are stationary during formation of a printed incremental layer or are stationary as otherwise described herein.
In some embodiments, the equipment assembly further comprises a bed transfer system adapted to transfer three-dimensionally printed beds, one or more at a time, away from the three-dimensional printing build system. In some embodiments, the bed transfer system is adapted to transfer three-dimensionally printed beds to one or more liquid removal systems and/or one or more harvesting systems. In some embodiments, the transfer system is integrated with the conveyor system, the liquid removal system or both.
In some embodiments, the liquid removal system comprises at least one dryer. In some embodiments, the liquid removal system is adapted to process two or more build plates and their contents at a time. In some embodiments, the liquid removal system is adapted to process two or more printed beds at a time. In some embodiments, the liquid removal system is adapted to process two or more printed articles at a time.
In some embodiments, the three-dimensionally printed powder bed comprises loose (unbound) powder and one or more three-dimensionally printed articles prior to harvesting of the printed article(s) from the loose powder. In some embodiments, the equipment assembly comprises one or more harvesting systems adapted to separate loose powder from the one or more three-dimensionally printed articles. In some embodiments, the harvesting system processes printed beds already processed by the liquid removal system. In some embodiments, the harvesting system comprises loose powder collector and three-dimensionally printed article collector. In some embodiments, the harvesting system comprises a vibrating or orbiting surface adapted to receive the three-dimensionally printed powder bed or the three-dimensionally printed articles. In some embodiments, the harvesting system comprises a vacuum conveyor with a screen to separate articles from loose powder. The vibrating surface can be perforated, non-perforated, corrugated, smooth or non-smooth to permit separation of loose powder from the printed articles.
In some embodiments, the equipment assembly further comprises a dedusting system adapted to remove loose particles from printed articles that have been harvested from a printed powder bed. A dedusting system can comprise a housing defining a dedusting region, one or more air jets, e.g. one or more air knives, that direct pressurized air into the dedusting region, one or more surfaces or retainers in the dedusting region for temporarily retaining one or more printed articles being dedusted, and one or more outlets through which air and removed particles exit the housing or dedusting region.
In some embodiments, the equipment assembly further comprises a build plate loading system adapted to place one or more build plates on the height adjustable platform(s) of the one or more build modules.
In some embodiments, the equipment assembly further comprises one or more powder recovery systems adapted to collect powder from the one or more systems of the equipment assembly and return it to a powder reservoir. The recovery system can comprise one or more loose powder collectors and one or more conduits for conducting loose powder from the one or more collectors to a powder reservoir. The recovery system can further comprise: a) one or more powder mixers for mixing recovered loose powder with virgin loose powder; b) one or more pressurized air powder handling systems that facilitate transfer of loose powder from one location to another; c) one or more vacuum powder handling systems that facilitate transfer of loose powder from one location to another; d) one or more mechanical powder handling systems that transfer loose powder from one location to another; e) one or more manual powder handling systems that transfer loose powder from one location to another; or a combination thereof.
In some embodiments, the equipment assembly further comprises a control system comprising one or more computerized controllers, one or more computers, and one or more user interfaces for one or more computers. In some embodiments, one or more components of the equipment assembly are computer controlled. In some embodiments, one or more components of the three-dimensional printing build system are computer controlled. In some embodiments, the conveyor system, the height adjustable platforms of the build modules, the at least one powder layering system and the at least one printing system are computer controlled. In some embodiments, the equipment assembly is adapted to spread layers of powder and deposit (print) droplets of liquid in a predetermined pattern on to the layers according to instructions provided by a computerized controller. In some embodiments, the predetermined pattern is based on one or more two-dimensional image files comprising pixels. In some embodiments, the two-dimensional image files are structured such that certain pixels indicate dispensing of droplets, and other pixels represent no dispensing of droplets. In some embodiments, the two-dimensional image files include different colors of pixels to indicate dispensing of different liquids, or no dispensing of liquid.
In some embodiments, the predetermined pattern for applying the liquid is the same in each incremental layer, is the same in two or more incremental layers, is different in one or more incremental layers, is different in all incremental layers, or is the same for a first group of incremental layer and the same for a second group of incremental layers but the pattern for the first group is different than the pattern for the second group.
In some embodiments, the equipment assembly further comprises one or more working surfaces, tables, gantries, enclosures, and/or platforms.
The invention also provides a three-dimensional printing equipment assembly comprising:
Some embodiments of the invention include those wherein: 1) at least one liquid removal system is present; 2) the equipment assembly further comprises at least one packaging system adapted to package one or more three-dimensionally printed articles; 3) the conveyor system is adapted to repeatedly transport the plural build modules, from the at least one powder layering system to the at least one printing system, in a linear manner, and not a radial manner, thereby facilitating Cartesian coordinate printing and not radial (polar coordinate) printing; 4) the equipment assembly further comprises a powder recovery system for recovering, and optionally recycling, unprinted powder; 5) the equipment assembly further comprises a liquid detector; 6) a liquid detector detects the presence of liquid in one or more printed incremental layers and/or in one or more printed articles; 7) the equipment assembly further comprises an inspection system; 8) an inspection system is a printed powder inspection system that determines the integrity of printing in one or more printed incremental layers and/or one or more printed articles and/or determines whether or not powder was properly applied in one or more incremental layers; 9) determining the integrity of printing comprises at least one of determining whether or not liquid has been correctly applied to one or more incremental layers according to one or more predetermined patterns and/or determining whether or not liquid has been correctly applied to one or more incremental layers according to a predetermined amount; 10) the inspection system is a printed article inspection system that determines whether or not one or more printed articles have the correct size, shape, weight, appearance, density, content and/or color; 11) the inspection system is a liquid application inspection system that monitors droplets of liquid applied by the print head to powder; 12) the inspection system comprises one or more cameras; and/or 13) a camera is independently selected at each occurrence from the group consisting of a visible wavelength camera, an UV wavelength camera, a near infrared wavelength camera, an x-ray camera and an infrared wavelength camera.
The invention includes all combinations of the embodiments, subembodiments and aspects disclosed herein. Accordingly, the invention includes the embodiments and aspects specifically disclosed, broadly disclosed, or narrowly disclosed herein, as well as combinations thereof and subcombinations of the individual elements of said embodiments and aspects.
Other features, advantages and embodiments of the invention will become apparent to those skilled in the art by the following description, accompanying examples.
The following figures form part of the present description and describe exemplary embodiments of the claimed invention. These drawings are not necessarily drawn to scale, and are instead intended to illustrate the general principles of the invention as further described herein. Although specific embodiments are described below with specific reference to the drawings provided, other embodiments are possible without deviating from the spirit and scope of the present invention. The skilled artisan will, in light of these figures and the description herein, be able to practice the invention without undue experimentation.
The invention provides an equipment assembly and system useful for the manufacture of articles via a three-dimensional printing process. The assembly and system are suitable for small scale/volume, medium scale/volume and large scale/volume preparation of articles. The three-dimensional printing process comprises forming an incremental layer of powder on a surface and subsequently printing/applying a liquid onto the layer, then repeating the steps of forming and printing a sufficient number of times to form a printed powder bed comprising one or more intended three-dimensionally printed articles and loose powder. Any excess/undesired liquid remaining in the article(s) is removed and the loose powder is separated from the article, which is then collected.
Generally, a three-dimensional printing equipment assembly or system comprises various subsystems including one or more three-dimensional printing build systems, one or more harvesting systems, and optionally one or more liquid removal systems. The equipment assembly can comprise one or more three-dimensional printing build systems, one or more harvesting systems, one or more liquid removal systems and optionally one or more other systems. In some embodiments, the equipment assembly further comprises one or more (sub)systems selected from one or more build plate loading systems, one or more powder recovery systems, one or more control systems, one or more build module or conveyor positioning systems, one or more conveyor drive motors, one or more bed transfer systems, or a combination of systems thereof.
As used herein, a “three-dimensional printing build system” generally comprises a conveyor system, plural build modules, at least one build station, and optionally one or more other components. The function of the three-dimensional printing build system is to form one or more three-dimensionally printed articles from a multilayered bed of powder in a build module. Plural build modules are engaged with a conveyor system that is adapted to conduct the build modules along a predetermined path which passes through one or more build stations. A build module is conducted to a powder layering system, and an incremental layer of powder is formed on the upper surface of a cavity of a build module. The build module is then conducted to a printing system, and a liquid is applied to the incremental layer of powder according to a predetermined pattern thereby forming a partially or fully bound powder layer (a printed incremental layer). The steps of conducting the build module, forming an incremental layer of powder and applying a liquid to the layer are considered to be a single build lap of the process. Build laps are repeated in build modules such that a printed incremental layer from one lap adheres to a printed incremental layer from a prior or subsequent lap. Build laps are repeated in build modules a sufficient number of times to form a three-dimensionally printed bed comprising one or more three-dimensionally printed articles and loose powder, wherein the three-dimensionally printed article comprises at least two printed incremental layers. The liquid applied to the pattern may or may not dry sufficiently under ambient conditions between build laps; therefore, a liquid removal step can be included between build laps. If, however, the liquid does not dry sufficiently between build laps, then an optional liquid removal step can be conducted following completion of all the build laps, i.e. following completion of a build cycle, for an intended three-dimensionally printed article.
The conveyor system is adapted to conduct build modules through a predetermined course/path during and between build laps. Substantially any system useful for conveying solid materials from a first location to a second location and back to the first location can be used. In some embodiments, the conveyor system is a cyclic, linear or oscillating conveyor system. In some embodiments, the cyclic conveyor system conducts build modules from the first location to a second location and then back to the first location. In some embodiments, the conveyor system is a cyclic or iterative conveyor system that conducts build modules two or more times through the same build station(s). In some embodiments, the linear conveyor system conducts build modules from a first build station to a second build station and optionally one or more other build stations. In some embodiments, the oscillating system conducts one or more build modules through at least one build station in a first direction and then conducts the one or more build modules through the at least one build station in an opposite direction.
The equipment assembly in
The build module (6j) is depicted passing through the powder dispensing region of a powder layering system (3). The build module (6k) is depicted between the powder layering system (3) and the printing system (4) and in the recovery region of an optional powder recovery system (11), which pick ups loose powder from the upper surface of build modules. The build module (6L), which is the first build module of the next build lap, is depicted passing through the printing region of the printing system (4). A control system, comprising at least one or more computers and one or more use interfaces (5), can be used to control and integrate (coordinate) operation of the various components and systems of the equipment assembly (1). In some embodiments, operation of each of the conveyor system, the height adjustable platforms of the build modules, the at least one powder layering system, and the at least one printing system are controlled by the control system. In some embodiments, operation of one or more of the build plate loading system (9), optional powder recovery system (11) and bed transfer system is controlled by the control system.
An equipment assembly can further comprise a bed transfer system (8) adapted to transfer three-dimensionally printed beds, one or more at a time, away from the three-dimensional printing build system. The exemplary bed transfer system (8) depicted is adapted to simultaneously remove two or more printed beds from respective build modules in a bed transfer region. In some embodiments, the bed transfer system is adapted to transfer three-dimensionally printed beds and corresponding build plates (and/or build modules), one or more at a time, away from the three-dimensional printing build system.
In some embodiments, a three-dimensional printing equipment assembly comprises:
A build module receives and retains powder deposited thereon by a powder layering system. In some embodiments, the build module comprises a height adjustable platform disposed within a cavity in the upper surface of the build module, wherein the cavity is defined by sidewalls. The height adjustable platform in combination with the sidewalls forms a cavity for the powder. The platform can be adapted to raise or lower incrementally. Powder is placed within the cavity and either directly or indirectly (such as by way of a build plate) onto the platform.
The height of an increment (thus the thickness of an incremental layer) can be controlled in different ways. In some embodiments, the height adjuster is computer controlled, whereby the computer controls raising or lowering of the height adjusting means by the size of an increment and/or by the number of increments. The size (vertical displacement) of an increment can vary from incremental layer to incremental layer, be the same from incremental layer to incremental layer or a combination thereof. In some embodiments, the size of the increment is the same for each incremental layer (build lap) of a build cycle, is different for one or more incremental layers of a build cycle, or a combination thereof.
The size of a vertical increment can be relative to a prior initial position of the build platform or the height adjuster of the powder fill head or both. For example, the platform is lowered within the cavity by a first increment to a first position relative to upper surface of the build module. A printed incremental layer is formed on the platform at the first position during a first build lap. The platform is then lowered by a second increment to a second position but relative to where it was at the first position. Another printed incremental layer is formed on the platform while at the second position during a second build lap. This process is repeated until completion of a build cycle.
The size of a vertical increment can be relative to one or more absolute positions of the platform in the cavity of a build module. For example, the build module can comprise plural encoders distributed vertically within or adjacent the cavity. The size of a first vertical increment, then, is defined by the absolute position (absolute vertical distance) of the platform with respect to a first encoder. When the platform is lowered by a second increment to a target second vertical position, which is determined according to or defined by the absolute vertical distance of the platform with respect to a second decoder. This type of absolute positioning can be exemplified as follows. If the target increment is 0.50 mm below the upper surface of a build module, the platform is commanded to drop 0.50 mm. If the next target increment is to be an additional 0.25 mm, then the platform is commanded to drop to a depth of 0.75 mm below the upper surface of the build module rather than to command it to drop by 0.25 mm relative to the initial 0.5 mm increment. This approach is generally superior to using relative moves (0.500, then 0.250) as any minor positioning errors will be resolved or at least not accumulate.
The build plate is adapted to fit within the upper cavity of a build module and to superpose a height adjustable platform within the cavity. The build plate receives and supports a powder bed and/or incremental powder layer(s). In some embodiments, the removable build plate is flat, porous, perforated, textured, coated, knurled, smooth or a combination thereof. Any regular and/or irregular geometric pattern for the arrangement of perforations can be used. The shape of the build plate can be varied as needed.
The optional build plate loading system is adapted to reload build plates onto the build modules engaged with the conveyor. In some embodiments, the build plate loading system is adapted to place one or more build plates on the height adjustable platform(s) of the one or more build modules. The build plate loading system (9) depicted in
The powder-layering system (3) depicted in
In some embodiments, a powder fill head (51) depicted in
The powder-height controller can raise or lower the powder spreader so as increase or decrease the thickness of a layer of powder placed onto the platform or a prior layer of powder on the platform. For example, if the platform is lowered by a first increment and the powder-height controller is raised by the same or another second increment, then the thickness of powder laid down will approximate the sum of the first and second increments. If the platform is lowered by a first increment and the powder-height controller is lower by a second increment, then the thickness of powder laid down will approximate the difference of the first increment minus the second increment. Alternatively, the powder spreader in combination with the powder-height controller can cooperate to compress a layer of powder that has been previously laid down. This can be accomplished by first laying down a layer of powder having a first thickness during a first build lap, lowering the powder-height controller and powder spreader and then passing the layer of powder under the lowered powder spreader thereby compressing the layer of powder.
In some embodiments, the powder spreader is a cylindrical roller the axis of which has a radial direction of motion opposite the linear direction of motion of a build module through the powder layering system. For example, the surface of the cylinder (64) has a linear direction (Arrow M) opposite the direction (Arrow J) of which an underlying build module (10) passes under the cylinder. In some embodiments, the powder spreader is a cylindrical roller, bar, rod, plate or straight smooth edge. Powder fill heads of other construction can be used.
The amount or rate of powder discharged from the powder fill head can be regulated with one or more controls. A powder discharge feedback controller can monitor the accumulation of powder at the powder spreader as the powder is being discharged from the powder fill head and spread to form an incremental powder layer. If the rate at which powder is released is too fast, an excessive amount of powder will accumulate at the powder spreader possibly causing it to spread the powder improperly. The feedback controller then sends a signal thereby causing the rate of powder discharge from the powder fill head to decrease. Conversely, if the feedback controller senses that the rate of powder discharge is too slow, it sends a signal thereby causing the rate of powder discharge to increase. The feedback controller can employ one or more visual, laser, acoustic or mechanical sensors or a combination thereof.
The equipment assembly (1) optionally comprises one or more powder recovery systems. The powder recovery system (11) depicted in
The print head of
A print head can comprise one or more print modules that deposit the liquid onto a layer of powder. The print head (28) of
Other suitable arrangements for the print modules are depicted in
By offsetting the print modules as depicted for module (33), the apparent overall print resolution of the print head can be increased. The print modules can be offset in staggered, interlaced, sobered, or angled arrangements relative to the print head in order to increase overall print density/resolution. For example, if the print resolution of each print module is 75 dpi (drops per inch), then the apparent overall print resolution of the print head (33) can be 75 dpi, 150 dpi, 225 dpi, 300 dpi, 375 dpi, 450 dpi or even higher. If the print resolution of each print modules is 100 dpi, then the apparent overall print resolution of the print head (33) can be 100 dpi, 200 dpi, 300 dpi, 400 dpi or even higher. In some embodiments, the print resolution of the print head is the same as or greater than the print resolution of a print module comprised within the print head. In some embodiments, the print resolution of the print head is a multiple of the print resolution of one or more print modules comprised within the print head. In some embodiments, the print resolution of the print head is the less than the print resolution of a print module comprised within the print head.
The arrangement of one or more print modules in the print head can be modified as needed to provide the desired printing result.
The print head (185) depicted in
In some embodiments, the one or more print heads is/are stationary when applying liquid onto an incremental layer, i.e. when printing. The one or more print heads can, in particular, be transversely and longitudinally stationary, with respect to the linear direction of motion of a build module (and thus an incremental layer of powder), when printing. Particular embodiments include those wherein: a) the printing is performed according to a Cartesian coordinate algorithm; b) the build module moves during printing in a linear direction that is perpendicular to the disposition of the print module (and one or more print heads); c) the print head and one or more print modules are stationary when printing (when applying liquid to an incremental layer of powder) and do not move in a direction that is transverse or longitudinal with respect to the direction of motion of the build module; and/or d) printing is not performed solely according to a polar coordinate algorithm
The three-dimensional printing system/assembly of the invention employs Cartesian coordinate based printing system and algorithms. Unlike other systems that move the print heads transversely and/or longitudinally when printing, the print heads of the invention are substantially stationary during printing. The term “transversely” is determined in relation to the direction of motion of a build module beneath a print head and means substantially perpendicular to the direction in which a build module is conducted through a printing area. The term “longitudinally” is determined in relation to the direction of motion of a build module beneath a print head and means substantially parallel to the direction in which a build module is conducted through a printing area. Application of liquid across the width of powder layer beneath a print head is accomplished by employing one or more print modules that individually or together traverse at least 75%, 80%, at least 85%, at least 90%, at least 95%, at least 97.5% or at least 99% the width of the powder layer. In the present case, the “width” of the powder layer is determined along a direction transverse to the direction of motion of a build module beneath a print head, and the term “length” is determined along a direction parallel to the direction of motion of a build module beneath a print head. In other words, a single print head can traverse the width or plural print heads transversely adjacent to each other can traverse the width of the powder layer.
In particular embodiments, the print head comprises plural print modules that individually do not but together do span the width of an incremental powder layer and/or of the cavity of a build module. In some embodiments, one or more print modules together modules span at least 50%, at least 55%, at least 75%, at least 90%, at least 95%, at least 99% or all of the width of the cavity of the build module. In particular embodiments, the build module moves in a first direction, and the print head is stationary when liquid is being applied to the incremental powder layer. In particular embodiments, printing is performed primarily or solely according to a Cartesian coordinate algorithm For example, the algorithm controls application of the droplets of the printing fluid relative to the linear (non-radial, straight) direction of the conveyor such that the print head applies droplets in a direction that is parallel (longitudinal) or is perpendicular (transverse) with respect to the linear direction of motion of the conveyor. The conveyor and corresponding build modules only move in a straight linear direction beneath the print head and build head.
An alternate embodiment of the invention is depicted in
In some embodiments, clusters of print modules, such as depicted in 17D, are arranged so their overall span covers only part of the width of a powder layer, such that plural print heads (each containing a cluster of print modules with interleaved jets) are required to cover the full width of the powder layer. For example, three print heads (189b), each having a cluster of print modules which together spans only 2.5″, would need to be arranged in a horizontally offset manner in order to cover the width of a powder bed or layer that is between 5 to 7.5 inches wide.
The at least one printing system can apply liquid according to any predetermined print pattern or randomly onto an incremental layer of powder. The pattern can be the same from incremental layer to incremental layer or can be different for one or more incremental layers of a printed article. Generally, two adjacent print patterns will comprise at least two overlapping printed portions such that at least a portion of the printed/bound powder in one printed incremental layer will adhere (be bound) to at least a portion of the printed/bound powder of an adjacent printed incremental layer. In this manner, plural stacked adjacent printed incremental layers adhere to each other thereby forming a three-dimensionally printed article comprising plural adjacent printed incremental layers of completely or partially bound powder. Even though a three-dimensionally printed article can include undercuts, overhangs, cavities, holes and other such features, at least part of the printed portions of adjacent printed incremental layers must adhere to one another in order to form and fill the composite volume of the article.
The printing system employs a Cartesian coordinate-based printing algorithm when applying liquid to an incremental powder layer. The system includes a computer and associated software that comprises one or more print jobs. A print job includes, among other things, information on the thickness of incremental layers and the predetermined pattern to be printed on the incremental layers of a printed article. The print job provides layer-by-layer instructions to the print head (print module(s)) about the creation and placement of droplets of liquid onto the incremental powder layer. The print job is based upon the series of two-dimensional images (slices) that, when stacked, together form a predetermined three-dimensional image (object).
Without being held bound to a particular mechanism, a target three-dimensional article is designed, such as with a CAD program. A virtual image of the target article is sliced virtually into plural stacked thinly-sliced images (which are referred to herein as “two-dimensional” images), wherein each two-dimensional image is actually the thickness of an incremental powder layer. The sum total of thicknesses of the image slices equals the total “height” of a target article. Each two-dimensional “image” is then converted into a subset of printing instructions, which together define a predetermined printing pattern for that image. All of the subsets of printing instructions are joined together to form a final set of printing instructions that are used by the computer to control printing. Aside from incremental layer thickness, two-dimensional shape of predetermined patterns, and shape of target article, the final set of print instructions also includes specification of or consideration of linear speed of the build module beneath the print head, rate of application of liquid to incremental powder layers, length and width of the incremental powder layer, dimensions of the cavity of a build module, incremental height adjustment of the height adjustable platform of the build module, rate of loading of powder into the powder fill head, rate of loading of powder into a build module to form an incremental layer, rate of transfer of powder from a feed reservoir to the fill head, resolution of the two dimensional image to be printed on each incremental layer, the number of applications of liquid to each incremental layer, application of one or more specific liquids to one or more specific locations of the incremental layer, starting and stopping of liquid application with respect to each build module, the number of articles to be printed, the number of build modules in the equipment assembly, the number of build modules to be printed upon, rate at which the platform of the build module moves down, timing for starting and stopping powder delivery relative to the entire build cycle, rotational speed of leveling device (roller) and other such parameters.
An equipment assembly comprises a control system comprising one or more controllers. Without being held bound to a particular mechanism, a homing switch located at a fixed point of the conveyor (
As described herein, the powder system can comprise one or more feedback controllers that determine the proper powder feed rate into a powder feeder and into the build modules. Likewise, the printing system can comprise one or more feedback controllers that determine the rate at which printing fluid (liquid) is being applied and/or consumed and can therefore control the liquid application rate and can also the reloading of liquid reservoir(s).
A liquid removal system, such as a dryer, can comprise one or more relative humidity controllers, temperature controllers and conveyor speed controllers. The system is therefore capable of adjusting drying time and conditions to provide printed articles containing the desired level of moisture.
In some embodiments, one or more components of the equipment assembly are computer controlled. A controller is independently selected at each occurrence from a computerized controller, electronic controller, mechanical controller or a combination thereof. In some embodiments, the control system comprises one or more computerized controllers, one or more computers, one or more user interfaces for one or more computers. In some embodiments, one or more components of the three-dimensional printing build system are computer controlled. In some embodiments, the conveyor system, the height adjustable platforms of the build modules, the at least one powder layering system and the at least one printing system are computer controlled. In some embodiments, the equipment assembly is adapted to spread layers of powder and print droplets of liquid in a predetermined pattern according to instructions provided by a computerized controller. In some embodiments, the predetermined pattern is based on one or more two-dimensional image files comprising pixels. In some embodiments, the two-dimensional image files are structured such that certain pixels indicate dispensing of droplets, and other pixels represent no dispensing of droplets. In some embodiments, the two-dimensional image files include different colors of pixels to indicate dispensing of different liquids, or no dispensing of liquid.
The equipment assembly of the invention can comprise one or more bed transfer systems adapted to transfer three-dimensionally printed beds, one or more at a time, away from the three-dimensional printing build system.
In some embodiments, the bed transfer system is adapted to transfer three-dimensionally printed beds to one or more liquid removal systems, one or more harvesting systems and/or one or more packaging systems. In some embodiments, the transfer system is integrated with the conveyor system, the liquid removal system or both.
A liquid removal system is adapted to receive one or more build plates (containing a printed bed) and to remove liquid from one or more printed powder layers onto which the liquid has been applied and/or from the three-dimensionally printed bed. A liquid removal system can be a process area through which one or more of the build modules are conducted. For example, the liquid removal system in
In some embodiments, the three-dimensionally printed bed comprises loose powder and one or more three-dimensionally printed articles. An equipment assembly of the invention can further comprise one or more harvesting systems adapted to separate loose powder from the one or more three-dimensionally printed articles. In some embodiments, the harvester processes build plates already processed by the liquid removal system. In some embodiments, the harvester comprises loose powder collection means and three-dimensionally printed article collection means. In some embodiments, the harvester comprises a vibrating and/or orbiting surface adapted to receive the three-dimensionally printed bed. In some embodiments, the harvester comprises one or more deagglomerators.
In some embodiments, the equipment assembly further comprises one or more dedusters adapted to remove loose powder from articles that have been harvested. In some embodiments, a deduster comprises one or more air brushes.
The exemplary combination harvester and deduster system (150) depicted in side elevation view in
The process tray of the deagglomerator vibrates (and/or orbits) and conducts the printed articles in the direction of Arrow B toward the deduster (157) while degglomerating the printed particles. The deduster also comprises a vibrating process tray adapted to remove and collect dust from the deagglomerated printed articles to provide dedusted printed articles (163). The finished printed articles (164) are conducted to a printed article collector (158). The deduster and/or deagglomerator can further comprise solids collector for collecting loose powder and/or agglomerates.
The deduster system (200) of
Loose powder, agglomerates or particulates collected during the build cycle, drying, harvesting, deagglomerating and/or dedusting can be disposed or can be blended to form recovered bulk material that can be milled (optionally) and recycled back into a feed supply of virgin unprinted bulk material. Such a bulk material recovery system can comprise one or more vacuum systems, one or more pressurized air systems, one or more non-vacuum mechanical systems, one or more manual systems or a combination thereof for transferring bulk material from one location to another.
As noted above, it takes plural build laps to construct a three-dimensionally printed article from a powder bed.
The print pattern used for individual print cycles can vary as needed and need not be the same for each build lap.
Upon completion of the exemplary print cycle, the three-dimensionally printed bed can be further processed as described herein.
Conveyor systems useful for conducting solid articles from one location to another during manufacture include, by way of example, a modular conveyor, non-modular conveyor, continuous conveyor, contiguous conveyor, conveyor belt, cam, pallet conveyor or link conveyor. Combinations thereof can be used.
The various components and systems of the equipment assembly will comprise parts made of durable materials such as metal, plastic, rubber or a combination thereof. In some embodiments, components of the equipment assembly comprise 304 or 316 stainless steel where possible.
The powder can comprise one or more materials suitable for pharmaceutical or non-pharmaceutical use. In some embodiments, the powder comprises one or more pharmaceutical excipients, one or more pharmaceutically active agents, or a combination thereof. In some embodiments, the three-dimensionally printed article is a pharmaceutical dosage form, medical device, medical implant, or other such article as described.
Exemplary types of pharmaceutical excipients that can be included in a three-dimensionally printed article include, by way of example and without limitation, chelating agent, preservative, adsorbent, acidifying agent, alkalizing agent, antifoaming agent, buffering agent, colorant, electrolyte, flavorant, polishing agent, salt, stabilizer, sweetening agent, tonicity modifier, antiadherent, binder, diluent, direct compression excipient, disintegrant, glidant, lubricant, opaquant, polishing agent, plasticizer, other pharmaceutical excipient, or a combination thereof.
Exemplary types of non-pharmaceutical excipients that can be included in a three-dimensionally printed article include, by way of example and without limitation, ash, clay, ceramic, metal, polymer, biological material, plastic, inorganic material, salt, other such materials or a combination thereof.
In some embodiments, the powder comprises one or more, two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more or plural components, each component being independently selected at each occurrence. In some embodiments, the equipment assembly comprises one or more, two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more or plural powder (or solid component) reservoirs.
Pharmaceutically active agents generally include physiologically or pharmacologically active substances that produce a systemic or localized effect or effects in animals, cells, non-humans and humans. When an active agent is present, any such agent can be used. Exemplary classes of active agents include, by way of example and without limitation, pesticides, herbicides, insecticides, antioxidants, plant growth instigators, sterilization agents, catalysts, chemical reagents, food products, nutrients, cosmetics, vitamins, sterility inhibitors, fertility instigators, microorganisms, flavoring agents, sweeteners, cleansing agents and other such compounds for pharmaceutical, veterinary, horticultural, household, food, culinary, agricultural, cosmetic, industrial, cleaning, confectionery and flavoring applications.
Whenever mentioned and unless otherwise specified, the term “active agent” includes all forms of the active agent including neutral, ionic, salt, basic, acidic, natural, synthetic, diastereomeric, isomeric, enantiomerically pure, racemic, hydrate, chelate, derivative, analog, optically active, optically enriched, free base, free acid, regioisomeric, amorphous, anhydrous and/or crystalline forms.
A three-dimensionally printed dosage form can comprise one, two or more different active agents. Particular combinations of active agents can be provided. Some combinations of active agents include: 1) a first drug from a first therapeutic class and a different second drug from the same therapeutic class; 2) a first drug from a first therapeutic class and a different second drug from a different therapeutic class; 3) a first drug having a first type of biological activity and a different second drug having about the same biological activity; 4) a first drug having a first type of biological activity and a different second drug having a different second type of biological activity. Exemplary combinations of active agents are described herein.
The active agent can be independently selected at each occurrence from active agents such as an antibiotic agent, antihistamine agent, decongestant, anti-inflammatory agent, antiparasitic agent, antiviral agent, local anesthetic, antifungal agent, amoebicidal agent, trichomonocidal agent, analgesic agent, anti-arthritic agent, anti-asthmatic agent, anticoagulant agent, anticonvulsant agent, antidepressant agent, antidiabetic agent, antineoplastic agent, anti-psychotic agent, neuroleptic agent, antihypertensive agent, hypnotic agent, sedative agent, anxiolytic energizer agent, antiparkinson agent, muscle relaxant agent, antimalarial agent, hormonal agent, contraceptive agent, sympathomimetic agent, hypoglycemic agent, antilipemic agent, ophthalmic agent, electrolytic agent, diagnostic agent, prokinetic agent, gastric acid secretion inhibitor agent, anti-ulcerant agent, anti-flatulent agent, anti-incontinence agent, cardiovascular agent or a combination thereof. A description of these and other classes of useful drugs and a listing of species within each class can be found in Martindale, The Extra Pharmacopoeia, 31ST Ed. (The Pharmaceutical Press, London 1996), the disclosure of which is incorporated herein by reference in its entirety.
The above-mentioned lists should not be considered exhaustive and are merely exemplary of the many embodiments considered within the scope of the invention. Many other active agents can be included in the powder of the invention.
The liquid applied to the powder can be a solution or suspension. The liquid can comprise an aqueous carrier, nonaqueous carrier, organic carrier or a combination thereof. The aqueous carrier can be water or an aqueous buffer. The nonaqueous carrier can be an organic solvent, low molecular weight polymer, oil, silicone, other suitable material, alcohol, ethanol, methanol, propanol, isopropanol, poly(ethylene glycol), glycol, other such materials or a combination thereof.
In some embodiments, the equipment assembly comprises one or more, two or more, three or more, four or more or plural liquid reservoirs. The liquid can be colored or non-colored. The liquid can comprise pigment, paint, dye, tint, ink or a combination thereof.
The liquid can comprise one or more solutes dissolved therein. The powder and/or liquid can comprise one or more binders.
The exemplary embodiments herein should not be considered exhaustive, but merely illustrative of only a few of the many embodiments contemplated by the present invention.
As used herein, the term “about” is taken to mean a value that is within ±10%, ±5% or ±1% of the indicated value.
The entire disclosures of all documents cited herein are hereby incorporated by reference in their entirety.
The following materials and procedure are used to prepare three-dimensionally printed dosage forms that dissolve rapidly in saliva.
A powder comprising at least one pharmaceutical carrier is loaded into the powder reservoir. A fluid comprising a liquid and at least one active ingredient is loaded into the fluid reservoir. The equipment assembly is operated, whereby plural stacked incremental layers of printed powder are sequentially formed in build modules by repeatedly passing the build modules through one or more build stations. Typically four to fifty incremental printed powder layers are formed and adhere to each other thereby forming a printed bed having one or more articles surrounded by or embedded in loose powder. The printed beds are dried in a dryer. The printed articles are separated from the loose powder with a harvester. The printed articles are then optionally dedusted with a deduster. The printed articles are then optionally packaged.
The above is a detailed description of particular embodiments of the invention. It will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. All of the embodiments disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure.
This application is a continuation of and claims the benefit U.S. Ser. No. 14/501,716 filed Sep. 30, 2014, which is a continuation and claims the benefit of U.S. Ser. No. 14/016,697, filed Sep. 3, 2013, now U.S. Pat. No. 8,888,480, issued Nov. 18, 2014, which is a continuation of and claims the benefit of PCT/US2013/057466 filed Aug. 30, 2013, which claims the benefit of provisional application 61/696,839 filed Sep. 5, 2012, the entire disclosures of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61696839 | Sep 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14501716 | Sep 2014 | US |
| Child | 15046714 | US | |
| Parent | 14016697 | Sep 2013 | US |
| Child | 14501716 | US | |
| Parent | PCT/US2013/057466 | Aug 2013 | US |
| Child | 14016697 | US |
