US20230321898A1 - Layer orientation control for pixel-based additive manufacturing - Google Patents
Layer orientation control for pixel-based additive manufacturing Download PDFInfo
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- US20230321898A1 US20230321898A1 US18/333,787 US202318333787A US2023321898A1 US 20230321898 A1 US20230321898 A1 US 20230321898A1 US 202318333787 A US202318333787 A US 202318333787A US 2023321898 A1 US2023321898 A1 US 2023321898A1
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- 238000004519 manufacturing process Methods 0.000 title abstract description 16
- 239000000654 additive Substances 0.000 title abstract description 13
- 230000000996 additive effect Effects 0.000 title abstract description 13
- 239000011347 resin Substances 0.000 claims abstract description 24
- 229920005989 resin Polymers 0.000 claims abstract description 24
- 238000005457 optimization Methods 0.000 claims 2
- 238000000034 method Methods 0.000 abstract description 25
- 230000000694 effects Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000007619 statistical method Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/10—Processes of additive manufacturing
- B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C64/124—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified
- B29C64/129—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using layers of liquid which are selectively solidified characterised by the energy source therefor, e.g. by global irradiation combined with a mask
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
- B29C64/227—Driving means
- B29C64/241—Driving means for rotary motion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
- B29C64/264—Arrangements for irradiation
- B29C64/268—Arrangements for irradiation using laser beams; using electron beams [EB]
- B29C64/273—Arrangements for irradiation using laser beams; using electron beams [EB] pulsed; frequency modulated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
- B29C64/264—Arrangements for irradiation
- B29C64/277—Arrangements for irradiation using multiple radiation means, e.g. micromirrors or multiple light-emitting diodes [LED]
- B29C64/282—Arrangements for irradiation using multiple radiation means, e.g. micromirrors or multiple light-emitting diodes [LED] of the same type, e.g. using different energy levels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/30—Auxiliary operations or equipment
- B29C64/386—Data acquisition or data processing for additive manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/40—Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
- B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y80/00—Products made by additive manufacturing
Definitions
- This invention relates generally to additive manufacturing, and more particularly to apparatus and methods for process control in pixel-based additive manufacturing.
- Additive manufacturing is a process in which material is built up layer-by-layer to form a component.
- Stereolithography is a type of additive manufacturing process which employs a vat of liquid ultraviolet (“UV”) curable photopolymer “resin” and an image projector to build components one layer at a time. For each layer, the projector flashes a light image of the cross-section of the component on the surface of the liquid, or just above a transparent lens at the bottom of the resin. The image is formatted as a grid array of pixels. Exposure to the ultraviolet light cures and solidifies the pattern in the resin and joins it to the layer below or above, depending on the specific build methodology.
- UV liquid ultraviolet
- the pixels are inherently square or rectangular.
- the dimensions of the pixels are can be in the range of 20-100 ⁇ m, with 40-80 ⁇ m being more common.
- a method of making a workpiece in an additive manufacturing process includes determining a preferred angular orientation of a grid array of one or more pixels about a build axis extending perpendicular to a layer to be built for a first layer of the workpiece.
- the preferred angular orientation is selected to align an edge of the one or more pixels with an edge of the layer of the workpiece being built.
- the method also includes orienting a patterned image of radiant energy to the preferred angular orientation by rotating a projector before solidifying a portion of a resin that forms the first layer of the workpiece.
- a method of making a workpiece includes positioning a resin below a build platform at a selected location along a build axis in a Z-axis direction that is perpendicular to the build platform.
- the build platform defines a plane in a X-Y direction.
- the method also includes rotating a projector about the build axis so as to orient the projector at a predetermined angular orientation about the build axis.
- the method further includes selectively curing the layer of the resin by projecting a patterned image of radiant energy onto the layer of the resin from the projector.
- the patterned image is configured as a grid pattern comprising rows and columns of pixels arrayed along the plane in the X-Y direction.
- the predetermined angular orientation is selected to align an edge of one or more of the pixels with an edge of the layer of the workpiece being built.
- an apparatus for making a workpiece is provided herein that may be used to perform any of the methods provided herein.
- the apparatus can include a platform movable along a build axis and positioned below a surface of a resin.
- a projector can be operable to project a patterned image of radiant energy comprising rows and columns of pixels along the surface of the resin.
- An actuator can be configured to change a relative angular orientation of the platform and the projector about the build axis from a nominal orientation for a first layer of the workpiece to an off-nominal orientation for a second layer of the workpiece.
- FIG. 1 is a schematic diagram illustrating a stereolithography apparatus
- FIG. 2 is a schematic perspective view of an exemplary workpiece that can be constructed using the apparatus of FIG. 1 ;
- FIG. 3 is a view taken along lines 3 - 3 of FIG. 2 ;
- FIG. 4 is a view taken along lines 4 - 4 of FIG. 2 ;
- FIG. 5 is a view of a layer of the workpiece shown in FIG. 2 with a grid pattern overlaid thereon;
- FIG. 6 is a view of a layer of the workpiece shown in FIG. 2 with a grid pattern overlaid thereon in a nominal orientation;
- FIG. 7 is a view of a layer of the workpiece shown in FIG. 2 with a grid pattern overlaid thereon in an optimized orientation.
- FIG. 1 illustrates schematically an stereolithography apparatus 10 suitable for carrying out an additive manufacturing method as described herein.
- Basic components of the apparatus 10 include a vat 12 containing a photopolymer resin 14 , a platform 16 connected to an actuator 18 , a projector 20 , and a controller 22 . Each of these components will be described in more detail below.
- the platform 16 is a rigid structure defining a planar worksurface 24 .
- the plane of the worksurface 24 is oriented parallel to an X-Y plane of the apparatus 10 , and a direction perpendicular to the X-Y plane is denoted as a Z-direction (X, Y, and Z being three mutually perpendicular directions).
- the Z-direction or Z-axis may also be referred to herein as a “build axis”.
- the actuator 18 is operable to move the platform 16 parallel to the Z-direction. It is depicted schematically in FIG. 1 , with the understanding devices such as pneumatic or hydraulic cylinders, ballscrew or linear electric actuators, and so forth, may be used for this purpose.
- the projector 20 may comprise any device operable to generate a radiant energy patterned image of suitable energy level and other operating characteristics to cure the resin 14 during the build process, described in more detail below.
- the projector 20 comprises a radiant energy source 26 such as a UV lamp, an image forming apparatus 28 operable to receive a source beam B from the radiant energy source 26 and generate a patterned image P comprising an array of individual pixels to be projected onto the surface of the resin 14 , and optionally focusing optics 30 , such as one or more lenses.
- the radiant energy source 26 may comprise any device operable to generate a beam of suitable energy level to cure the resin 14 .
- the radiant energy source 26 comprises a UV flash lamp.
- the image forming apparatus 28 may include one or more mirrors, prisms, and/or lenses and provided with suitable actuators, and arranged so that the source beam “B” from the radiant energy source 26 can be transformed into a pixelated image in an X-Y plane coincident with the worksurface 24 .
- the image forming apparatus 28 may be a digital micromirror device.
- the controller 22 is a generalized representation of the hardware and software required to control the operation of the apparatus 10 , including the projector 20 and actuator 18 .
- the controller 22 may be embodied, for example, by software running on one or more processors embodied in one or more devices such as a programmable logic controller (“PLC”) or a microcomputer.
- PLC programmable logic controller
- Such processors may be coupled to sensors and operating components, for example, through wired or wireless connections.
- the same processor or processors may be used to retrieve and analyze sensor data, for statistical analysis, and for feedback control.
- a build process begins by positioning the platform 16 just below the surface of the resin 14 , thus defining a selected layer increment.
- the projector 20 projects a patterned image P representative of the cross-section of the workpiece on the surface of the resin 14 . Exposure to the radiant energy cures and solidifies the pattern in the resin 14 .
- the platform 16 is then moved vertically downward by the layer increment.
- the projector 20 again projects a patterned image P. Exposure to the radiant energy cures and solidifies the pattern in the resin 14 and yet joins it to the previously-cured layer below. This cycle of moving the 16 and then curing the resin 14 is repeated until the entire workpiece is complete.
- means are provided for rotating the projector 20 and the platform 16 relative to each other about the Z-axis. Rotation of either the projector 20 , or the platform 16 , or both are suitable to carry out the method described herein.
- an actuator 32 is provided which is operable to controllably rotate the projector 20 .
- FIG. 2 shows an exemplary workpiece 34 which takes the form of an elongated hollow structure having opposed side walls 36 and opposed end walls 38 , extending between a lower end 40 and an upper end 42 .
- FIG. 3 illustrates a representative plan view of the workpiece 34 at the lower end 40 .
- the workpiece 34 is oriented such that the side walls 36 are parallel to a nominal X-axis direction (corresponding to the X-axis of the stereolithography apparatus 10 described above).
- the end walls 38 are perpendicular to the side walls 36 , and are therefore parallel to a nominal Y-axis direction (corresponding to the Y-axis of the stereolithography apparatus 10 ).
- FIG. 1 shows an exemplary workpiece 34 which takes the form of an elongated hollow structure having opposed side walls 36 and opposed end walls 38 , extending between a lower end 40 and an upper end 42 .
- FIG. 3 illustrates a representative plan view of the workpiece 34 at the lower end 40 .
- the workpiece 34 is oriented such
- FIG. 4 illustrates a representative plan view of the workpiece 34 at the upper end 42 , with the workpiece in the same orientation as FIG. 3 .
- the side walls 36 are not parallel to the nominal X-axis direction, and the end walls 38 are not parallel to the Y-axis.
- the cross-sections of the workpiece at the lower and upper ends 40 , 42 are rotated relative to each other about a nominal Z-axis direction. This type of structure may be described as “twisted”.
- the workpiece 34 is modeled as a stack of planar layers arrayed along the Z-axis. It will be understood that the actual workpiece 34 may be modeled and/or manufactured as a stack of dozens or hundreds of layers.
- FIG. 5 illustrates a single representative layer at the lower end 40 of the workpiece 34 .
- the cross-sectional shape of the workpiece 34 overlaid with a grid array of pixels 44 comprising mutually perpendicular rows (X-direction) and columns (Y-direction).
- the pixels 44 may be quadrilateral shapes such as rectangles or more particularly squares.
- each edge of the workpiece 34 is parallel to either the X-axis or the Y-axis.
- the edge of a rectangular pixel parallel to the X-axis or Y-axis could always be aligned with the workpiece edge, given a suitably small pixel dimension.
- FIG. 6 illustrates a single representative layer taken at the upper end 42 of the workpiece 34 , again overlaid with a grid of pixels 44 . Because no edge of the workpiece 34 is parallel to either the X-axis or the Y-axis, it is not always possible to align the edge of a rectangular pixel parallel to a workpiece edge. Accordingly, no matter how small the pixel dimension, some degree of stair-stepping will occur, as described above.
- the angular orientation of the projector 20 (and thus the X-Y grid orientation) relative to the workpiece 34 may be individually selected for each layer.
- the layer orientation may be set at a nominal angular orientation, which is herein identified as being at 0° rotation.
- flashing of the patterned image P may occur at the nominal angular orientation, with the expectation that the edges of pixels will be substantially aligned with the edges of the workpiece 34 .
- the layer orientation may be set at a different angular orientation in order to achieve the best correspondence between the X-Y grid orientation and the workpiece edges.
- the workpiece cross-section at the upper end 42 is rotated approximately 30° counterclockwise relative to the workpiece cross-section at the lower end 40 .
- the X-Y grid orientation may be rotated approximately 30° counterclockwise.
- the projector 20 would be rotated approximately 30° counterclockwise and the flashing of the patterned image P may occur at this new angular orientation, with the expectation that the edges of pixels 44 will again be substantially aligned with the edges of the workpiece 34 .
- This new off-nominal orientation may be referred to as a “preferred orientation” or an “optimized orientation”.
- a software optimization algorithm determines an optimized fit or best fit for each layer. For example, it is possible to compute for a given angular orientation how many pixels 44 in the layer would cross a part edge, or to compute for a given angular orientation the total surface area of pixels 44 crossing a part edge. The orientation may then be varied and the computations repeated until one or more of these values are minimized, resulting in an optimized angular orientation.
- the optimum angular orientation for each layer may be achieved with only a 90° range of rotation.
- angular orientation of a layer it is also possible when determining angular orientation of a layer to consider the fidelity and surface quality of the workpiece along the Z-axis. For example, considering the twisted prismatic workpiece 34 described above, it is apparent that if the optimum angular orientation is used for each layer individually, the exterior surface of the finished workpiece 34 may exhibit a “terraced” effect. In order to reduce or minimize this effect, the angular orientation of each layer may be alternated between a nominal (0°) orientation and an optimized orientation, or the orientation may be randomized for each layer. This would produce improved surface quality along the Z-axis, at the expense of incurring some amount of stair stepping in the individual layers.
- the method described herein has several advantages over the prior art. It method enhances fidelity for pixel-based layer manufactured components. This process ensures that various pixels are utilized with respect to the various geometries and their relative locations in the build to optimize the features at those respective locations in the component. It will provide increased ability to produce critical part geometry, reduce variability and increase yield, resulting in lower part cost.
- stereolithography apparatus 10 described above is merely an example used for the purposes of explanation.
- the method described herein is effective with any method of additive manufacturing in which a starting material is solidified, where the solidifying force is applied using a grid of pixels.
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Abstract
A method of making a workpiece in an additive manufacturing process includes determining a preferred angular orientation of the grid array about a build axis extending perpendicular to a layer to be built for a first layer of a workpiece. The preferred angular orientation is selected to align an edge of one or more pixels with an edge of the layer of the workpiece being built. The method further includes orienting a patterned image of radiant energy to the preferred angular orientation by rotating a projector before solidifying a portion of a resin that forms the first layer of the workpiece.
Description
- This application claims priority to U.S. Non-Provisional application Ser. No. 17/072,119, entitled “LAYER ORIENTATION CONTROL FOR PIXEL-BASED ADDITIVE MANUFACTURING,” filed on Oct. 16, 2020, which is a continuation application of U.S. Non-Provisional application Ser. No. 15/217,548, entitled “LAYER ORIENTATION CONTROL FOR PIXEL-BASED ADDITIVE MANUFACTURING,” filed on Jul. 22, 2016. The entire contents of the above-referenced applications are hereby incorporated by reference in its entirety for all purposes.
- This invention relates generally to additive manufacturing, and more particularly to apparatus and methods for process control in pixel-based additive manufacturing.
- Additive manufacturing is a process in which material is built up layer-by-layer to form a component. Stereolithography is a type of additive manufacturing process which employs a vat of liquid ultraviolet (“UV”) curable photopolymer “resin” and an image projector to build components one layer at a time. For each layer, the projector flashes a light image of the cross-section of the component on the surface of the liquid, or just above a transparent lens at the bottom of the resin. The image is formatted as a grid array of pixels. Exposure to the ultraviolet light cures and solidifies the pattern in the resin and joins it to the layer below or above, depending on the specific build methodology.
- The pixels are inherently square or rectangular. The dimensions of the pixels are can be in the range of 20-100 μm, with 40-80 μm being more common.
- One problem with this method is that, no matter how small the pixels are, there will still be situations in which the edge of the area to be cured is not in alignment with a pixel, and the pixel protrudes past the intended border. This type of error is referred to as “stair stepping”.
- This problem is addressed by a method of pixel-based additive manufacturing in which an angular orientation of each build layer is set independently.
- In some embodiments of the present disclosure, a method of making a workpiece in an additive manufacturing process is provided that includes determining a preferred angular orientation of a grid array of one or more pixels about a build axis extending perpendicular to a layer to be built for a first layer of the workpiece. The preferred angular orientation is selected to align an edge of the one or more pixels with an edge of the layer of the workpiece being built. The method also includes orienting a patterned image of radiant energy to the preferred angular orientation by rotating a projector before solidifying a portion of a resin that forms the first layer of the workpiece.
- In some embodiments of the present disclosure, a method of making a workpiece is provided that includes positioning a resin below a build platform at a selected location along a build axis in a Z-axis direction that is perpendicular to the build platform. The build platform defines a plane in a X-Y direction. The method also includes rotating a projector about the build axis so as to orient the projector at a predetermined angular orientation about the build axis. The method further includes selectively curing the layer of the resin by projecting a patterned image of radiant energy onto the layer of the resin from the projector. The patterned image is configured as a grid pattern comprising rows and columns of pixels arrayed along the plane in the X-Y direction. The predetermined angular orientation is selected to align an edge of one or more of the pixels with an edge of the layer of the workpiece being built.
- In some embodiments of the present disclosure, an apparatus for making a workpiece is provided herein that may be used to perform any of the methods provided herein. The apparatus can include a platform movable along a build axis and positioned below a surface of a resin. A projector can be operable to project a patterned image of radiant energy comprising rows and columns of pixels along the surface of the resin. An actuator can be configured to change a relative angular orientation of the platform and the projector about the build axis from a nominal orientation for a first layer of the workpiece to an off-nominal orientation for a second layer of the workpiece.
- These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
- The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:
-
FIG. 1 is a schematic diagram illustrating a stereolithography apparatus; -
FIG. 2 is a schematic perspective view of an exemplary workpiece that can be constructed using the apparatus ofFIG. 1 ; -
FIG. 3 is a view taken along lines 3-3 ofFIG. 2 ; -
FIG. 4 is a view taken along lines 4-4 ofFIG. 2 ; -
FIG. 5 is a view of a layer of the workpiece shown inFIG. 2 with a grid pattern overlaid thereon; -
FIG. 6 is a view of a layer of the workpiece shown inFIG. 2 with a grid pattern overlaid thereon in a nominal orientation; and -
FIG. 7 is a view of a layer of the workpiece shown inFIG. 2 with a grid pattern overlaid thereon in an optimized orientation. - Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,
FIG. 1 illustrates schematically anstereolithography apparatus 10 suitable for carrying out an additive manufacturing method as described herein. Basic components of theapparatus 10 include avat 12 containing aphotopolymer resin 14, aplatform 16 connected to anactuator 18, aprojector 20, and acontroller 22. Each of these components will be described in more detail below. - The
platform 16 is a rigid structure defining aplanar worksurface 24. For purposes of convenient description, the plane of theworksurface 24 is oriented parallel to an X-Y plane of theapparatus 10, and a direction perpendicular to the X-Y plane is denoted as a Z-direction (X, Y, and Z being three mutually perpendicular directions). The Z-direction or Z-axis may also be referred to herein as a “build axis”. - The
actuator 18 is operable to move theplatform 16 parallel to the Z-direction. It is depicted schematically inFIG. 1 , with the understanding devices such as pneumatic or hydraulic cylinders, ballscrew or linear electric actuators, and so forth, may be used for this purpose. - The
projector 20 may comprise any device operable to generate a radiant energy patterned image of suitable energy level and other operating characteristics to cure theresin 14 during the build process, described in more detail below. In the illustrated example, theprojector 20 comprises aradiant energy source 26 such as a UV lamp, animage forming apparatus 28 operable to receive a source beam B from theradiant energy source 26 and generate a patterned image P comprising an array of individual pixels to be projected onto the surface of theresin 14, and optionally focusingoptics 30, such as one or more lenses. - The
radiant energy source 26 may comprise any device operable to generate a beam of suitable energy level to cure theresin 14. In the illustrated example, theradiant energy source 26 comprises a UV flash lamp. - The
image forming apparatus 28 may include one or more mirrors, prisms, and/or lenses and provided with suitable actuators, and arranged so that the source beam “B” from theradiant energy source 26 can be transformed into a pixelated image in an X-Y plane coincident with theworksurface 24. In the illustrated example theimage forming apparatus 28 may be a digital micromirror device. - The
controller 22 is a generalized representation of the hardware and software required to control the operation of theapparatus 10, including theprojector 20 andactuator 18. Thecontroller 22 may be embodied, for example, by software running on one or more processors embodied in one or more devices such as a programmable logic controller (“PLC”) or a microcomputer. Such processors may be coupled to sensors and operating components, for example, through wired or wireless connections. The same processor or processors may be used to retrieve and analyze sensor data, for statistical analysis, and for feedback control. - Generically, a build process begins by positioning the
platform 16 just below the surface of theresin 14, thus defining a selected layer increment. Theprojector 20 projects a patterned image P representative of the cross-section of the workpiece on the surface of theresin 14. Exposure to the radiant energy cures and solidifies the pattern in theresin 14. Theplatform 16 is then moved vertically downward by the layer increment. Theprojector 20 again projects a patterned image P. Exposure to the radiant energy cures and solidifies the pattern in theresin 14 and yet joins it to the previously-cured layer below. This cycle of moving the 16 and then curing theresin 14 is repeated until the entire workpiece is complete. - Additionally, means are provided for rotating the
projector 20 and theplatform 16 relative to each other about the Z-axis. Rotation of either theprojector 20, or theplatform 16, or both are suitable to carry out the method described herein. In the illustrated example, anactuator 32 is provided which is operable to controllably rotate theprojector 20. -
FIG. 2 shows anexemplary workpiece 34 which takes the form of an elongated hollow structure having opposedside walls 36 andopposed end walls 38, extending between alower end 40 and anupper end 42.FIG. 3 illustrates a representative plan view of theworkpiece 34 at thelower end 40. Theworkpiece 34 is oriented such that theside walls 36 are parallel to a nominal X-axis direction (corresponding to the X-axis of thestereolithography apparatus 10 described above). Theend walls 38 are perpendicular to theside walls 36, and are therefore parallel to a nominal Y-axis direction (corresponding to the Y-axis of the stereolithography apparatus 10).FIG. 4 illustrates a representative plan view of theworkpiece 34 at theupper end 42, with the workpiece in the same orientation asFIG. 3 . At this location it can be seen that theside walls 36 are not parallel to the nominal X-axis direction, and theend walls 38 are not parallel to the Y-axis. Stated another way, the cross-sections of the workpiece at the lower and upper ends 40, 42 are rotated relative to each other about a nominal Z-axis direction. This type of structure may be described as “twisted”. - In order to produce the
workpiece 34 using theapparatus 10, theworkpiece 34 is modeled as a stack of planar layers arrayed along the Z-axis. It will be understood that theactual workpiece 34 may be modeled and/or manufactured as a stack of dozens or hundreds of layers. -
FIG. 5 illustrates a single representative layer at thelower end 40 of theworkpiece 34. The cross-sectional shape of theworkpiece 34 overlaid with a grid array ofpixels 44 comprising mutually perpendicular rows (X-direction) and columns (Y-direction). Thepixels 44 may be quadrilateral shapes such as rectangles or more particularly squares. With theworkpiece 34 in this particular orientation, each edge of theworkpiece 34 is parallel to either the X-axis or the Y-axis. Thus it is apparent that the edge of a rectangular pixel parallel to the X-axis or Y-axis could always be aligned with the workpiece edge, given a suitably small pixel dimension. - In contrast,
FIG. 6 illustrates a single representative layer taken at theupper end 42 of theworkpiece 34, again overlaid with a grid ofpixels 44. Because no edge of theworkpiece 34 is parallel to either the X-axis or the Y-axis, it is not always possible to align the edge of a rectangular pixel parallel to a workpiece edge. Accordingly, no matter how small the pixel dimension, some degree of stair-stepping will occur, as described above. - To counter this effect and improve part fidelity, the angular orientation of the projector 20 (and thus the X-Y grid orientation) relative to the
workpiece 34 may be individually selected for each layer. - For example, in the process of modeling and building the layer shown in
FIG. 4 , the layer orientation may be set at a nominal angular orientation, which is herein identified as being at 0° rotation. As noted above, flashing of the patterned image P may occur at the nominal angular orientation, with the expectation that the edges of pixels will be substantially aligned with the edges of theworkpiece 34. - In order to model and build a layer shown in
FIG. 6 , the layer orientation may be set at a different angular orientation in order to achieve the best correspondence between the X-Y grid orientation and the workpiece edges. In the illustrated example, the workpiece cross-section at theupper end 42 is rotated approximately 30° counterclockwise relative to the workpiece cross-section at thelower end 40. Accordingly, as shown inFIG. 7 , the X-Y grid orientation may be rotated approximately 30° counterclockwise. During the build process, theprojector 20 would be rotated approximately 30° counterclockwise and the flashing of the patterned image P may occur at this new angular orientation, with the expectation that the edges ofpixels 44 will again be substantially aligned with the edges of theworkpiece 34. This new off-nominal orientation may be referred to as a “preferred orientation” or an “optimized orientation”. - For a simple workpiece involving a twisted prismatic shape as described above, or other type of component having edges which are orthogonal to each other but rotated relative to the nominal X-Y axes, there is likely a specific angular orientation for each layer which provides exact correspondence between the pixel edges and the workpiece edges.
- For other types of workpiece sectional shapes, it is possible to use a software optimization algorithm to determine an optimized fit or best fit for each layer. For example, it is possible to compute for a given angular orientation how
many pixels 44 in the layer would cross a part edge, or to compute for a given angular orientation the total surface area ofpixels 44 crossing a part edge. The orientation may then be varied and the computations repeated until one or more of these values are minimized, resulting in an optimized angular orientation. - In any case, because the
pixels 44 are individually addressable along two mutually perpendicular axes, the optimum angular orientation for each layer may be achieved with only a 90° range of rotation. - It is also possible when determining angular orientation of a layer to consider the fidelity and surface quality of the workpiece along the Z-axis. For example, considering the twisted
prismatic workpiece 34 described above, it is apparent that if the optimum angular orientation is used for each layer individually, the exterior surface of thefinished workpiece 34 may exhibit a “terraced” effect. In order to reduce or minimize this effect, the angular orientation of each layer may be alternated between a nominal (0°) orientation and an optimized orientation, or the orientation may be randomized for each layer. This would produce improved surface quality along the Z-axis, at the expense of incurring some amount of stair stepping in the individual layers. - The method described herein has several advantages over the prior art. It method enhances fidelity for pixel-based layer manufactured components. This process ensures that various pixels are utilized with respect to the various geometries and their relative locations in the build to optimize the features at those respective locations in the component. It will provide increased ability to produce critical part geometry, reduce variability and increase yield, resulting in lower part cost.
- It is noted that the
stereolithography apparatus 10 described above is merely an example used for the purposes of explanation. The method described herein is effective with any method of additive manufacturing in which a starting material is solidified, where the solidifying force is applied using a grid of pixels. - The foregoing has described an apparatus and method for layer orientation control in a pixel-based additive manufacturing process. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
- Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
- The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying potential points of novelty, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
Claims (21)
1-20. (canceled)
21. An apparatus for making a workpiece, comprising:
a platform movable along a build axis;
a projector operable to project a patterned image of radiant energy comprising rows and columns of pixels along a surface of a resin; and
an actuator configured to change a relative angular orientation of the platform and the projector about the build axis from a nominal orientation for a first layer of the workpiece to an off-nominal orientation for a second layer of the workpiece.
22. The apparatus of claim 21 , wherein the platform is moved downward along the build axis between the first layer and the second layer.
23. The apparatus of claim 21 , wherein the projector comprises:
a radiant energy source; and
an image forming apparatus.
24. The apparatus of claim 23 , wherein the radiant energy source comprises an ultraviolet flash lamp.
25. The apparatus of claim 21 , wherein the actuator is positioned above the projector along the build axis.
26. The apparatus of claim 21 , wherein the relative angular orientation of the first layer and the second layer are selected based on a surface quality of the workpiece along the build axis.
27. The apparatus of claim 21 , further comprising:
a controller operably coupled with the projector and the actuator, the controller configured to determine the relative angular orientation of the platform and the projector about the build axis from the nominal orientation.
28. The apparatus of claim 21 , wherein the rows and the columns of the pixels projected from the projector are rotated as the relative angular orientation of the platform and the projector about the build axis is moved from the nominal orientation to the off-nominal orientation.
29. An apparatus for making a workpiece, comprising:
a platform movable along a build axis;
a projector operable to project a patterned image of radiant energy comprising rows and columns of pixels along a surface of a resin; and
an actuator configured to change a relative angular orientation of the platform and the projector about the build axis from a nominal orientation for a first layer of the workpiece to an off-nominal orientation for a second layer of the workpiece; and
a controller operably coupled with the projector and the actuator, the controller configured to implement an optimization algorithm to minimize a number or area of the pixels crossing a periphery of an edge of the first layer of the workpiece.
30. The apparatus of claim 29 , wherein the patterned image of radiant energy is configured as a two-dimensional grid array of the pixels.
31. The apparatus of claim 29 , wherein the resin is a photopolymer and the patterned image is projected using ultraviolet light.
32. The apparatus of claim 29 , wherein the controller is configured to determine a preferred angular orientation of a grid array of one or more pixels about the build axis extending perpendicular to the second layer from the first layer of the workpiece, wherein the preferred angular orientation is selected to align an edge of the one or more pixels with an edge of the second layer of the workpiece being built.
33. The apparatus of claim 32 , wherein the controller is configured to orient the patterned image of radiant energy to the preferred angular orientation by rotating the projector before solidifying a portion of the resin that forms the first layer of the workpiece.
34. The apparatus of claim 32 , wherein the projector comprises:
a radiant energy source; and
an image forming apparatus.
35. The apparatus of claim 32 , wherein at least the second layer is stacked on the first layer along the build axis, and the preferred angular orientation of the first layer and the second layer are selected based at least partially on a surface quality of the workpiece along the build axis.
36. An apparatus for making a workpiece, comprising:
a platform movable along a build axis;
a projector operable to project a patterned image of radiant energy comprising rows and columns of pixels along a surface of a resin; and
an actuator configured to change a relative angular orientation of the platform and the projector about the build axis from a nominal orientation for a first layer of the workpiece to an off-nominal orientation for a second layer of the workpiece, wherein the rows and the columns of the pixels projected from the projector are rotated as the relative angular orientation of the platform and the projector about the build axis is moved from the nominal orientation to the off-nominal orientation.
37. The apparatus of claim 36 , further comprising:
a controller operably coupled with the projector and the actuator, the controller configured to implement an optimization algorithm to minimize a number or area of the pixels crossing a periphery of an edge of the first layer of the workpiece.
38. The apparatus of claim 36 , wherein the platform is moved downward along the build axis between the first layer and the second layer.
39. The apparatus of claim 36 , wherein the projector comprises:
a radiant energy source; and
an image forming apparatus.
40. The apparatus of claim 39 , wherein the radiant energy source comprises an ultraviolet flash lamp.
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US18/333,787 US20230321898A1 (en) | 2016-07-22 | 2023-06-13 | Layer orientation control for pixel-based additive manufacturing |
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---|---|---|---|---|
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EP1894705B1 (en) | 2004-05-10 | 2010-08-25 | Envisiontec GmbH | Method and device for creating a three dimensional object with resolution enhancement by means of pixel shift |
US7617192B2 (en) | 2005-03-09 | 2009-11-10 | Medio Systems, Inc. | Method and system for capability content search with mobile computing devices |
US7758799B2 (en) | 2005-04-01 | 2010-07-20 | 3D Systems, Inc. | Edge smoothness with low resolution projected images for use in solid imaging |
CN101960577A (en) | 2008-01-02 | 2011-01-26 | 得克萨斯州大学***董事会 | Micro element is made |
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US9751262B2 (en) | 2013-06-28 | 2017-09-05 | General Electric Company | Systems and methods for creating compensated digital representations for use in additive manufacturing processes |
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US10207363B2 (en) | 2014-03-24 | 2019-02-19 | James Eldon Craig | Additive manufacturing temperature controller/sensor apparatus and method of use thereof |
CN105773962B (en) | 2014-12-25 | 2018-07-13 | 信泰光学(深圳)有限公司 | 3D projects print system and its method |
US10252468B2 (en) * | 2016-05-13 | 2019-04-09 | Holo, Inc. | Stereolithography printer |
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