WO2019195708A1

WO2019195708A1 - Systems and methods for increasing an additive manufacturing build area size

Info

Publication number: WO2019195708A1
Application number: PCT/US2019/026033
Authority: WO
Inventors: Scott Goodrich; Andrew CAUNTER
Original assignee: 3D Fortify
Priority date: 2018-04-06
Filing date: 2019-04-05
Publication date: 2019-10-10

Abstract

Systems for increasing an additive manufacturing build area are provided. A projector can include a stationary light source producing an image within a projection area. The projector can include a first mirror moveable to a plurality of positions in the projection area and, for each of the plurality of positions, producing a respective reflected image from the image. The projector can include a second mirror producing a respective second reflected image from each of the reflected images. Each second reflected image can correspond to a respective portion of a planar build area of the three-dimensional printing system. The plurality of second reflected images can encompass an entirety of the planar build area.

Description

SYSTEMS AND METHODS FOR INCREASING AN ADDITIVE MANUFACTURING

BUILD AREA SIZE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application No. 62/653900, titled “SYSTEMS AND METHODS FOR INCREASING AN ADDITIVE MANUFACTURING

BUILD AREA SIZE,” filed on April 6, 2018, which is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] Additive manufacturing (sometimes referred to as three-dimensional printing) can be used to fabricate complex three-dimensional structures using materials such as polymers, metals, and ceramics. The printing of a three-dimensional part can be accomplished by selectively curing successive layers of a photo-curable precursor material, with each layer corresponding to a layer of the finished part. A projector can direct an image formed from radiation (e.g., ultraviolet light) towards a planar build area corresponding to the layer to be formed to selectively cure the precursor material in the vicinity of the build area. The shape of the layer corresponds to the shape of the image produced by the projector. Thus, the size of the build area can be limited by the maximum size of the image produced by the projector.

SUMMARY

[0003] One aspect of this disclosure is directed to a projector for use in a three-dimensional printing system. The projector can include a stationary light source producing an image within a projection area. The projector can include a first mirror moveable to a plurality of positions in the projection area and, for each of the plurality of positions, producing a respective reflected image from the image. The projector can include a second mirror producing a respective second reflected image from each of the reflected images. Each second reflected image can correspond to a respective portion of a planar build area of the three-dimensional printing system. The plurality of second reflected images can encompass an entirety of the planar build area.

[0004] In some implementations, the first mirror can be configured to rotate to two positions.

In some implementations, the second mirror can be stationary. In some implementations, the projector can further include a third stationary mirror. In some implementations, the second mirror and the third mirror can each be configured to produce a respective one of the plurality of second reflected images. In some implementations, the light source can be configured to produce the projected image by emitting light in a direction substantially parallel to the build area.

[0005] In some implementations, the first mirror can be configured to rotate to four positions.

In some implementations, the light source can produce the projected image by emitting light in a direction perpendicular to the build area. In some implementations, the second mirror can be coupled to the first mirror such that the first mirror and the second mirror rotate together.

[0006] In some implementations, the projector can include an actuator configured to rotate one of the first mirror or the second mirror. In some implementations, the projector can include a control system. In some implementations, the control system can be configured to receive information defining a three-dimensional model to be built by the three-dimensional printing system. In some implementations, the control system can be configured to generate a plurality of layers of the model each corresponding to a respective cross-sectional portion of the model. In some implementations, for each layer, the control system can be configured to generate a plurality of subsections of the layer each corresponding to one of the portions of the build area.

In some implementations, the control system can be configured to control the light source and the actuator to project images corresponding to the subsections in their respective portions of the build area.

[0007] Another aspect of this disclosure is directed to a projector for use in a three-dimensional printing system. The projector can include a stationary light source producing an image within a projection area. The projector can include a first mirror having a surface positioned within the projection area to produce a reflected image from the image. The projector can include a second mirror movable to a plurality of positions and, for each of the plurality of positions producing a respective second reflected image from the reflected image. The projector can include a third mirror producing a respective plurality of third reflected images from each second reflected image. Each third reflected image can correspond to a respective portion of a planar build area of the three-dimensional printing system. The plurality of third reflected images can encompass an entirety of the planar build area.

[0008] In some implementations, the second mirror can be configured to rotate to four positions. In some implementations, the light source can produce the projected image by emitting light in a direction parallel to the build area. In some implementations, the third mirror can be coupled to the second mirror such that the second mirror and the third mirror rotate together. In some implementations, the light source can produce the projected image by emitting light in a direction parallel to the build area. In some implementations, the third mirror can be one mirror of a first pair of mirrors. In some implementations, the projector can further include a second pair of mirrors. Each pair of mirrors can be configured to produce a respective one of the plurality of third reflected images.

[0009] In some implementations, the first mirror and the third mirror can be stationary.

[0010] In some implementations, the projector can include an actuator can be configured to rotate the second mirror. In some implementations, the projector can include a control system. In some implementations, the control system can be configured to receive information defining a three-dimensional model to be built by the three-dimensional printing system. In some implementations, the control system can be configured to generate a plurality of layers of the model each corresponding to a respective cross-sectional portion of the model. In some implementations, for each layer, the control system can be configured to generate a plurality of subsections of the layer each corresponding to one of the portions of the build area. In some implementations, the control system can be configured to control the light source and the actuator to project images corresponding to the subsections in their respective portions of the build area.

[0011] Another aspect of this disclosure is directed to a method for fabricating a three- dimensional object. The method can include receiving, by a controller, information defining a three-dimensional model of the three-dimensional object. The method can include generating, by the controller, a layer of the model corresponding to a respective cross-sectional portion of the model. The method can include generating, by the controller, a plurality of subsections of the layer each corresponding to a respective portion of a planar build area. The method can include positioning, by the controller, a build plate at a predetermined height corresponding to the build area within a reservoir containing a precursor material. For each portion of the planar build area, the method can include moving, by the controller, a first mirror of a plurality of mirrors into a position corresponding to the portion of the planar build area. The method can also include activating, by the controller, a light source to project an image in the portion of the planar build area to solidify the precursor material, the image corresponding to the respective subsection of the layer.

[0012] In some implementations, the first mirror can be moveable to a plurality of positions in a projection area of the light source. In some implementations, the plurality of mirrors can further include a second mirror configured to receive a reflected image from the first mirror and to produce the image corresponding to the respective subsection of the layer. In some implementations, moving the first mirror can include rotating the first mirror within the projection area of the light source. In some implementations, the first mirror and the second mirror can be coupled with one another. In some implementations, the method can further include rotating the first mirror and the second mirror together.

[0013] In some implementations, the plurality of mirrors can further include a second stationary mirror positioned within a projection area of the light source. In some

implementations, the first mirror can be configured to receive a reflected image from the second mirror and to produce the image corresponding to the respective subsection of the layer. In some implementations, moving the first mirror can include rotating the first mirror.

[0014] In some implementations, moving the first mirror can include driving, by the controller, an actuator coupled with the first mirror to rotate the first mirror into the position corresponding to the portion of the planar build area.

[0015] In some implementations, the method can include generating, by the controller, a plurality of additional layers of the model corresponding to respective additional cross-sectional portions of the model. In some implementations, the method can include generating, by the controller, a plurality of subsections of each layer. In some implementations, each subsection can correspond to a respective portion of the planar build area.

[0016] Another aspect of this disclosure is directed to a projector for use in a three-dimensional printing system. The projector can include a stationary light source producing an image within a projection area. The projector can include a first mirror moveable to a plurality of positions in the projection area and, for each of the plurality of positions, producing a respective reflected image from the image. The projector also can include a second mirror producing a respective second reflected image from each of the reflected images. Each second reflected image can correspond to a respective portion of a planar build area of the three-dimensional printing system. Together, the plurality of second reflected images can encompass an entirety of the planar build area.

[0017] Another aspect of this disclosure is directed to a projector for use in a three-dimensional printing system. The projector can include a stationary light source producing an image within a projection area. The projector can include a first mirror having a surface positioned within the projection area to produce a reflected image from the image. The projector can include a second mirror movable to a plurality of positions and, for each of the plurality of positions producing a respective second reflected image from the reflected image. The projector also can include a third mirror producing a respective plurality of third reflected images from each second reflected image. Each third reflected image can correspond to a respective portion of a planar build area of the three-dimensional printing system. Together, the plurality of third reflected images can encompass an entirety of the planar build area.

[0018] These and other aspects and arrangements are discussed in detail below. The foregoing information and the following detailed description include illustrative examples of various aspects and arrangements, and provide an overview or framework for understanding the nature and character of the claimed aspects and arrangements. The drawings provide illustration and a further understanding of the various aspects and arrangements, and are incorporated in and constitute a part of this specification

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are not intended to be drawn to scale. Like reference numbers and designations in the various drawings indicate like elements. For purposes of clarity, not every component may be labeled in every drawing.

[0020] FIG. 1 is a perspective view of an example system for additive manufacturing, according to an illustrative implementation.

[0021] FIG. 2 A is a perspective view of an example projector that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative

implementation.

[0022] FIG. 2B is a block diagram representation of the projector shown in FIG. 2A, according to an illustrative implementation.

[0023] FIG. 2C is a perspective view of a portion of the example projector shown in FIG. 2A, according to an illustrative implementation.

[0024] FIG. 3 is a perspective view of a portion of a second example projector that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation. [0025] FIG. 4 is a perspective view of a portion of a third example projector that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation.

[0026] FIG. 5 is a perspective view of a portion of a fourth example projector that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation.

[0027] FIG. 6 is a perspective view of a portion of a fifth example projector that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation.

[0028] FIG. 7 is a flow diagram of an example method that can be used to construct a three- dimensional part, according to an illustrative implementation.

DETAILED DESCRIPTION

[0029] Following below are more detailed descriptions of various concepts related to, and implementations of systems and methods for increasing an additive manufacturing build area size. The concepts introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

[0030] FIG. 1 is a perspective view of an example system 100 for additive manufacturing, according to an illustrative implementation. The additive manufacturing system 100 can be used to form a three-dimensional part. The system 100 includes a projector 105 positioned beneath a reservoir 107 that is supported on a platform 109. The reservoir 107 includes a transparent lower surface and can be configured to contain a precursor material. The projector 105 is positioned beneath the lower surface of the reservoir 107 and is configured to direct radiation (e.g., UV light) through the transparent lower surface of the reservoir 107 to consolidate a layer of the precursor material. A build plate 111 provides the surface on which the part is manufactured, which can be referred to as the build area. The build plate 111 can be coupled to a frame 113 that supports the build plate 111 over the reservoir and allows the build plate to be raised and lowered into and out of the reservoir 107 as the part is manufactured.

[0031] In general, the precursor material contained within the reservoir 107 can be used to build the part one layer at a time. To build the first layer, the build plate 111 is lowered into the precursor material towards the lower surface of the reservoir 107. The projector 105 is then activated to selectively consolidate portions of the precursor material in a pattern selected according to a desired shape of the first layer of the part. In some implementations, the projector projects radiation in the form of an image having a shape that corresponds to the desired cross- sectional shape of the first layer of the part. Exposure to the radiation from the projector 105 causes the precursor material to become selectively consolidated in the appropriate shape and to adhere to the surface of the build plate 111, thereby forming the first layer of the part.

Subsequent layers can be formed in a similar way. For example, the build plate 111 can be raised by a distance equal to the height of a single layer of the part, and the projector 105 can be activated again to selectively consolidate the precursor material and to cause the selectively consolidated portion of the precursor material to adhere to the previous layer. These steps can be repeated for each subsequent layer of the part until the complete part has been formed. [0032] Because the projected image generated by the projector 105 defines the cross-sectional shape of each layer of the part, the maximum size of the part is limited by the maximum size of the projected image. Generally, a projector produces an image at a focal point. The image travels through a lens toward the build area, and the size of the image at the build area is directly proportional to the path length between the focal point and the build area. Thus, one technique for increasing the size of the projected image at the build area is simply to increase the path length by moving the projector farther away from the build area. However, this requires a corresponding increase in the overall size of the additive manufacturing system in order to accommodate the increased path length. Thus, achieving a desired build area size using this technique can result in an additive manufacturing system that is prohibitively large.

[0033] This disclosure provides systems and methods for increasing the effective build area size for additive manufacturing applications that overcome the limitations described above. In particular, a projector for an additive manufacturing system such as the system 100 can include a light source and a dynamic mirror array controllable to effectively increase the size of an image produced by the light source in a build area. At least one of the mirrors in the array can be movable in a rotational or translational fashion. In some implementations, subsets of the mirrors can be configured to produce reflected images each having a fixed size at a position that is spatially translated with respect to the other reflected images so that the edges of the reflected images are positioned adjacent to one another (or partially overlap), such that the reflected images together encompass an entirety of the build area. Thus, the effective size of the build area can be increased by a factor equal to the number of reflected images capable of being produced by the mirror array. For example, a mirror array configured to produce two reflected images can be used to implement a projector capable of doubling the effective build area size of a light source included in the projector. Similarly, a mirror array configured to produce four reflected images can be used to implement a projector capable of quadrupling the effective build area size of a light source included in the projector. These and other aspects are of this disclosure are described further below.

[0034] FIG. 2A is a perspective view of an example projector 202 that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative

implementation. In some implementations, the projector 202 can be used in a system such as the system 100 shown in FIG. 1. FIG. 2B is a block diagram representation of the projector 202 shown in FIG. 2 A, according to an illustrative implementation. FIGS. 2 A and 2B are described together below.

[0035] Referring to both FIG. 2 A and FIG. 2B, the projector 202 includes a light source 205 and a plurality of mirrors 2l0a-2l0f (generally referred to as mirrors 210) collectively forming a dynamic mirror array. A controller 215 can be communicatively coupled to the projector 202. The controller 215 can receive files 220 corresponding to a three-dimensional part to be fabricated. The controller 215 can include a layer generating module 225, a layer processing module 230, a mirror array driver 235, and a projector driver 240. The light source 205 and the mirrors 210 direct light (e.g., UV light) onto the planar build area 250 to selectively cure a precursor material. Although omitted from FIG. 2 A for illustrative purposes, a reservoir containing the precursor material can be positioned in the planar build area 250, and a build plate can be placed in the reservoir such that its surface substantially coincides with the planar build area 250.

[0036] As described above, in conventional systems, the size of the planar build area 250 can be directly proportional to the path length between the focal point of the light source 205 and the planar build area 250 and, as a result, increasing the size of the planar build area 250 can require the light source 205 to be moved farther away, which contributes to an increased size of the overall projector 202. The mirrors 210 can be configured to address this issue by allowing an increased size of the planar build area 250 without increasing the path length. In particular, the mirrors 210 can be configured to reflect an image produced by the light source 205 into any of the regions 260a-260d (generally referred to as regions 260) of the planar build area 250. Thus, relative to a system not implementing a dynamic mirror array, the projector 202 can effectively quadruple the size of the planar build area 250 without a corresponding increase in path length.

[0037] Light exits the light source 205 in a direction parallel to a surface of the planar build area 250, and is reflected at an angle of about 90 degrees by the mirror 2l0a, which can be maintained in a fixed location and orientation. This reflected light is reflected again by the central mirror 2l0b. The mirror 2l0b is configured to rotate about the central axis 248 to four positions, each corresponding to a respective one of outer the mirrors 2l0c-2l0f. For example, when rotated to a first position, the mirror 210b is configured to reflect the light received from the mirror 2l0a towards the outer mirror 2l0c. In a second rotational position, the mirror 210b is configured to reflect light towards the outer mirror 2l0d. In a third rotational position, the mirror 110b is configured to reflect light towards the outer mirror 2l0e. In a fourth rotational position, the mirror 210b is configured to reflect light towards the outer mirror 21 Of. The outer mirrors 2l0c-2l0f are in turn configured to reflect light towards a respective one of the regions 260 of the planar build area 250.

[0038] Thus, in order to project an image onto the region 260a of the planar build area 250, the mirror 210b is rotated to a first position such that light emitted from the light source 205 follows a path from the mirror 2l0a, to the mirror 210b, to the mirror 2l0c, and finally to the region 260a of the planar build area 250. This is illustrated in FIG. 2C, which shows a perspective view of a portion of the example projector 202 shown in FIG. 2 A. In FIG. 2C, the arrows represent the light rays traveling between the light source 205 and the region 260a of the planar build area 250.

[0039] In should be understood that the paths used to project an image onto the regions 260b, 260c, and 260d of the planar build area 250 are symmetric about the central axis 248 with respect to the path illustrated in FIG. 2C. For example, to project an image onto the region 260b of the planar build area 250, the mirror 210b is rotated to a second position such that light emitted from the light source 205 follows a path from the mirror 2l0a, to the mirror 210b, to the mirror 2l0d, and finally to the region 260b of the planar build area 250. Similarly, to project an image onto the region 260c of the planar build area 250, the mirror 210b is rotated to a third position such that light emitted from the light source 205 follows a path from the mirror 2l0a, to the mirror 210b, to the mirror 2l0e, and finally to the region 260c of the planar build area 250. Finally, to project an image onto the region 260d of the planar build area 250, the mirror 210b is rotated to a fourth position such that light emitted from the light source 205 follows a path from the mirror 2l0a, to the mirror 210b, to the mirror 21 Of, and finally to the region 260d of the planar build area 250.

[0040] While the projector 202 provides an increased effective size of the planar build area 250, it should be understood that the technique described above requires the light source 205 to produce four successive images (each corresponding to a respective one of the regions 260) in order to encompass the entire planar build area 250. The controller 215 shown in FIG. 2B can be configured to cause the projector 202 to produce these successive images in a manner that results in the correct cross-sectional shape for each layer of the part under construction, which can be represented by the 3D model files 220. [0041] In some implementations, the files 220 can be computer aided design files (for example, .stl files) that specify the architecture of the part to be produced. The controller 215 receives the files 220 and processes the files 220 to generate a set of instructions to cause the projector 202 to generate appropriate images to form each layer of the part. For example, the layer generating module 225 can be configured to produce a set of layers based on the architecture of the part represented by the files 220. In some implementations, the layer generating module 225 can create a set of layers of the part by dividing the part into slices each having a thickness equal to a desired thickness for each layer. The layer generating module 225 can determine the dimensions for each layer, as well as the position of each layer within the overall part. The layer generating module 225 can store this information, for example, in the database 244.

[0042] The layer processing module 230 can receive data corresponding to each layer generated by the layer generating module 225. For each layer, the layer processing module 230 can generate data corresponding to the images that should be output by the light source corresponding to each region 260 of the planar build area 250. As described above, light emitted by the light source 205 is selectively directed to each of the regions 260 by selectively rotating the mirror 210b into a corresponding position. Thus, the images for each region 260 are rotated relative to one another when they reach the planar build area 250. For example, the rotation of the mirror 210b from a first position corresponding to the region 260a to a second position 260b can cause the images reflected into each of these regions to be rotated 90 degrees relative to one another. In some implementations, the layer processing module 230 can generate the data corresponding to the images to be output by the light source for each region 260 of the planar build area 250 in a manner that accounts for this rotation. For example, the data corresponding to the image to be output for the region 260b can indicate that the image should be rotated by 90 degrees relative to the image to be output for the region 260a.

[0043] The mirror array driver 235 can be configured to cause the rotational mirror 210b to move into an appropriate position for each respective region 260 of the planar build area 250 for a given layer, and the light source driver 240 can cause the light source 205 to output the image corresponding to each respective region 260, as determined by the layer processing module 230. For example, the light source driver 240 causes the light source 205 to output the image for the region 260a after the mirror array driver causes the mirror 210b to move into the first position corresponding to the region 260a. The light source driver 240 then causes the light source 205 to output the image for the region 260b once the mirror array driver has caused the mirror 210b to move into the second position corresponding to the region 260b, and so on until the light source has projected the appropriate image onto each region 260 of the planar build area 250 for a given layer. In this way, the entire layer is cured.

[0044] The build plate driver 243 can be configured to cause the build plate to be raised or lowered with respect to the reservoir containing the precursor material. In some

implementations, the build plate driver 243 causes the build plate to be raised by a distance equal to the thickness of a single layer after each layer of the part has been completed. The

functionality described above to consolidate a single layer can then be repeated for each successive layer of the part until the part has been completed. For example, after the build plate driver 243 has caused the build plate to be raised by an appropriate distance for a new layer, the mirror array driver 235 can cause the mirrors 210 to move into their respective positions corresponding to the region 260a of the build area 250. The light source driver 240 then activates the light source 205 to consolidate the precursor material within the region 260a. The mirror array driver 235 and the light source 240 perform similar steps corresponding to each of the regions 260b-260c of the build area 250, and the build plate driver 243 causes the build plate to be raised by a distance equal to the thickness of one layer such that the next layer of the part can be built. The functionality described above to consolidate a single layer can then be repeated for each successive layer of the part until the part has been completed.

[0045] It should be understood that the arrangement of the mirrors 2l0a in FIGS. 2A and 2C is illustrative only, and that other arrangements also can be used without departing from the scope of this disclosure. For example, in some implementations, rather than including four outer mirrors 2l0c-2l0f at fixed positions corresponding to respective regions 260 of the planar build area 250, the same principles can be used in a system that includes only a single outer mirror (e.g., the mirror 2l0c). In such an arrangement, to account for the absence of the mirrors 2l0d- 21 Of, the mirror 2l0c can be configured to rotate into the positions occupied by the mirrors 2l0d-2l0f along with the central rotational mirror 210b. Stated another way, the mirror 210b and the mirror 2l0a can rotate together about the central axis 248 as a coupled pair. Thus, a first position of the central mirror 210b and the outer mirror 2l0c can be used to reflect an image onto the region 260a, a second position of the central mirror 210b and the outer mirror 2l0c can be used to reflect an image onto the region 260b, and so on. In this example, the mirror array driver 235 can be configured to cause both the central mirror 210b and the outer mirror 2l0c to move into appropriate positions corresponding to each of the regions 260 of the planar build area 250.

[0046] FIG. 3 is a perspective view of a portion of a second example projector 302 that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation. The projector 302 operates according to principles similar to those described above in connection with the projector 202, and like reference numerals refer to like elements. It should be understood that certain components (such as a controller) are omitted from the depiction of the projector 302 in FIG. 3 for illustrative purposes. In some

implementations, such components are included in the projector 302, and perform the same functionality as described above in connection with the projector 202 of FIGS. 2A-2C.

[0047] Like the projector 202 of FIG. 2 A, the projector 302 can be used to quadruple the effective size of the build area 350. In particular, the build area 350 can be divided into four regions 360, and a dynamic mirror array can be configured to selectively reflect images produced by the light source onto each respective region 360. FIG. 3 illustrates the path of light projected onto the region 360a. As shown, the projector 300 includes a central mirror 3 lOb and an outer mirror 3 lOc. The central mirror 3 lOb can be configured to rotate about the axis 348 into four positions each corresponding to a respective one of the regions 360 of the build area 350. In the depiction of FIG. 3, the mirror 3 lOb is positioned to reflect light towards the outer mirror 3 lOc, which in turn reflects the light onto the region 360a of the build area 350.

[0048] The projector 302 differs from the projector 202 of FIG. 2 A in that the light source 305 of the projector 302 is oriented to emit light in a direction perpendicular to the plane of the build area 350 along the axis 348, as illustrated by the light rays emanating from the light source 305. As a result, in the projector 302, there is no need for a mirror corresponding to the mirror 2l0a of the projector 202 that served to reflect light emitted perpendicular to the axis 248 by the light source 205 in a direction parallel to the axis 248, as the light source of the projector 302 directs light along the axis 348 with no reflection whatsoever. The mirror 3 lOb and the mirror 3 lOc serve purposes similar to that of the mirrors 210b and 2l0c, respectively, of the projector 202. In some implementations, the central mirror 3 lOb and the outer mirror 3 lOc can be configured to rotate together as a coupled pair into four positions about the axis 348, with the depiction of FIG. 3 corresponding to one of the positions. Each of the three positions not illustrated in FIG. 3 can correspond to a respective one of the regions 360b, 360c, and 360d of the planar build area 350. It should be understood that, in some other implementations, the outer mirror 3 lOc can remain in a fixed position, while only the central mirror 3 lOb rotates. In such implementations, the projector 302 can also include three additional outer mirrors positioned at regular intervals around the central axis 348, each corresponding to a respective one of the regions 360b, 360c, and 360d of the planar build area 350. For example, these additional outer mirrors can correspond to the outer mirrors 2l0d-2l0f of the projector 202 shown in FIG. 2 A.

[0049] FIG. 4 is a perspective view of a portion of a third example projector 402 that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation. The projector 402 operates according to principles similar to those described above in connection with the projector 202, and like reference numerals refer to like elements. It should be understood that certain components (such as a controller) are omitted from the depiction of the projector 402 in FIG. 4 for illustrative purposes. In some

implementations, such components are included in the projector 402, and perform the same functionality as described above in connection with the projector 202 of FIGS. 2A-2C.

[0050] The projector 402 can be used to double the effective size of the build area 450. In particular, the build area 450 can be divided into two regions 460a and 460b, and a dynamic mirror array can be configured to selectively reflect images produced by a light source onto each respective region 460. FIG. 4 illustrates the path of light (represented by line segments between the mirrors 410) projected from the light source 405 onto the regions 460a and 460b. As shown, the projector 402 includes a central mirror 410b and two outer mirrors 4l0c and 4l0d. The central mirror 410b can be configured to rotate about the central axis 448 into two positions each corresponding to a respective one of the regions 460a and 460b of the build area 450. As indicated in FIG. 4, the central mirror 410b is depicted in both positions for illustrative purposes. In a first rotational position, the central mirror 410b receives light emitted in a direction parallel to the surface of the planar build area 450 by the light source 405, and reflects this light towards the outer mirror 4l0c. The outer mirror 4l0c in turn reflects the light onto the region 460a of the planar build area 450. In its second rotational position, the central mirror 410b receives light emitted by the light source and reflects the light towards the outer mirror 4l0d. The outer mirror 4l0d in turn reflects the light onto the region 460b of the planar build area 450. Together, the regions 460a and 460b encompass the entire planar build area 450.

[0051] In some implementations, the projector 402 can instead include only a single outer mirror, such as the outer mirror 4l0c. In such an implementation, to account for the absence of the outer mirror 4l0d, the outer mirror 4l0c can be configured to move (e.g., rotationally) into two positions, one of which is depicted in FIG. 4 and the other of which corresponds to the position of the outer mirror 4l0d in FIG. 4. In some such implementations, the central mirror 410b and the outer mirror 4l0c can be configured to rotate as a coupled pair about the central axis 448.

[0052] It should be understood that, when used in connection with the projector 402, the functionality of a controller such as the controller 215 of FIG. 2B can be modified to account for the structural differences between the projector 202 and the projector 402. For example, a layer processing module used in the projector 402 can divide each layer into two sections, each corresponding to a respective one of the regions 460a and 460b of the planar build area 450, rather than into four sections as was described in connection with the layer processing module 230 of FIG. 2B, and the orientation of one section can be mirrored with respect to the orientation of the other section, to account for the rotation of the image caused by rotation of the central mirror 4l0b about the central axis 448.

[0053] FIG. 5 is a perspective view of a portion of a fourth example projector 502 that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation. The projector 502 operates according to principles similar to those described above in connection with the projector 202, and like reference numerals refer to like elements. It should be understood that certain components (such as a controller) are omitted from the depiction of the projector 502 in FIG. 5 for illustrative purposes. In some

implementations, such components are included in the projector 502, and perform the same functionality as described above in connection with the projector 202 of FIGS. 2A-2C.

[0054] The projector 502 can be used to quadruple the effective size of the build area 550. In particular, the build area 550 can be divided into four regions 560a-560d, and a dynamic mirror array can be configured to selectively reflect images produced by a light source onto each respective region 560. FIG. 5 illustrates the path of light (represented by line segments between the mirrors 510) projected from the light source 505 onto the regions 560a and 560b. As described below, the light paths traversed to project images onto the regions 560c and 560d can be symmetric to the paths associated with the regions 560a and 560b, respectively, although they are omitted from FIG. 5 for clarity.

[0055] As shown, the projector 502 includes a central mirror 510b and four outer mirrors 5l0c- 51 Of. The central mirror 410b can be configured to rotate about the central axis 548 into four positions each corresponding to a respective one of the regions 560 of the build area 550. As indicated in FIG. 5, the central mirror 5l0b is depicted in two positions (corresponding to the regions 560a and 560b) for illustrative purposes. In its first position, the central mirror 5l0b receives light emitted in a direction perpendicular to and away from the surface of the planar build area 550 by the light source 505, and reflects this light towards the outer mirror 5l0c. The outer mirror 5l0c reflects light towards the outer mirror 5l0d, which in turn reflects the light onto the region 560a of the planar build area 550. In its second position, the central mirror 5l0b receives light emitted by the light source 505 and reflects the light towards the outer mirror 5l0e. The outer mirror 5l0e reflects the light towards the outer mirror 51 Of, which in turn reflects the light onto the region 560b of the planar build area 550.

[0056] As described above, the path of light from the light source to the region 560c of the planar build area 550 can be symmetric to the path of light from the light source to the region 560a. Thus, in some implementations, the projector 502 can further include additional outer mirrors corresponding to and positioned symmetrically across the central axis 548 from the outer mirrors 5l0c and 5l0d, which can be configured to reflect light towards to region 560c. The central mirror 510b also can be configured to rotate into an additional position such that it reflects light towards these additional outer mirrors. In some other implementations, the outer mirrors 5l0c and 5l0d themselves can be rotated into a symmetric position across the central axis 548 from their positions illustrated in FIG. 5 to reflect light towards the region 560c, thereby dispensing with the need for additional outer mirrors.

[0057] Similarly, the path of light from the light source to the region 560d of the planar build area 550 can be symmetric to the path of light from the light source to the region 560b. Thus, in some implementations, the projector 502 can further include additional outer mirrors

corresponding to and positioned symmetrically across the central axis 548 from the outer mirrors 5 lOe and 5 lOf, which can be configured to reflect light towards to region 560d. The central mirror 510b also can be configured to rotate into an additional position such that it reflects light towards these additional outer mirrors. In some other implementations, the outer mirrors 5l0e and 51 Of themselves can be rotated into a symmetric position across the central axis 548 from their positions illustrated in FIG. 5 to reflect light towards the region 560d, thereby dispensing with the need for additional outer mirrors.

[0058] FIG. 6 is a perspective view of a portion of a fifth example projector 602 that can be used to increase a build area size in a system for additive manufacturing, according to an illustrative implementation. The projector 602 operates according to principles similar to those described above in connection with the projector 202, and like reference numerals refer to like elements. It should be understood that certain components (such as a controller) are omitted from the depiction of the projector 602 in FIG. 6 for illustrative purposes. In some

implementations, such components are included in the projector 602, and perform the same functionality as described above in connection with the projector 202 of FIGS. 2A-2C.

[0059] The projector 602 can be used to quadruple the effective size of the build area 650. In particular, the build area 650 can be divided into four regions 660a-660d, and a dynamic mirror array can be configured to selectively reflect images produced by a light source onto each respective region 660. FIG. 6 illustrates the path of light (represented by line segments between the mirrors 610) projected by a light source 605 onto the regions 660a and 660b. As described below, the light paths traversed to project images onto the regions 660c and 660d can be symmetric to the paths associated with the regions 660a and 660b, respectively, although they are omitted from FIG. 6 for clarity.

[0060] As shown, the projector 602 includes a first mirror 6l0a that serves to receive light emitted from the light source 605 in a direction parallel to the planar build surface 660 and to reflect this light. In some implementations, the mirror 6l0a can be configured to remain in a fixed position. The projector 602 also includes a central mirror 61 Ob and four outer mirrors 6l0c-6l0f. The central mirror 61 Ob can be configured to rotate about the central axis 648 into four positions each corresponding to a respective one of the regions 660 of the build area 650.

As indicated in FIG. 6, the central mirror 610b is depicted in two positions (corresponding to the regions 660a and 660b) for illustrative purposes. In its first position, the central mirror 610b receives light reflected by the mirror 6l0a and reflects this light towards the outer mirror 6l0c. The outer mirror 6l0c reflects light towards the outer mirror 6l0d, which in turn reflects the light onto the region 660a of the planar build area 650. In its second position, the central mirror 610b receives light from the mirror 6l0a and reflects the light towards the outer mirror 6l0e. The outer mirror 6l0e reflects the light towards the outer mirror 61 Of, which in turn reflects the light onto the region 660b of the planar build area 650.

[0061] As described above, the path of light from the light source to the region 660c of the planar build area 650 can be symmetric to the path of light from the light source to the region 660a. Thus, in some implementations, the projector 602 can further include additional outer mirrors corresponding to and positioned symmetrically across the central axis from the outer mirrors 6l0c and 6l0d, which can be configured to reflect light towards to region 660c. The central mirror 610b also can be configured to rotate into an additional position such that it reflects light towards these additional outer mirrors. In some other implementations, the outer mirrors 6l0c and 6l0d themselves can be rotated into a symmetric position across the central axis 648 from their positions illustrated in FIG. 6 to reflect light towards the region 660c, thereby dispensing with the need for additional outer mirrors.

[0062] Similarly, the path of light from the light source to the region 660d of the planar build area 650 can be symmetric to the path of light from the light source to the region 660b. Thus, in some implementations, the projector 602 can further include additional outer mirrors corresponding to and positioned symmetrically across the central axis from the outer mirrors 6l0e and 61 Of, which can be configured to reflect light towards to region 660d. The central mirror 61 Ob also can be configured to rotate into an additional position such that it reflects light towards these additional outer mirrors. In some other implementations, the outer mirrors 6l0e and 61 Of themselves can be rotated into a symmetric position across the central axis 648 from their positions illustrated in FIG. 6 to reflect light towards the region 660d, thereby dispensing with the need for additional outer mirrors.

[0063] FIG. 7 is a flow diagram of an example method 700 that can be used to construct a three-dimensional part, according to an illustrative implementation. The method 700 can be performed using a three-dimensional printing system such as the system 100 shown in FIG. 1, along with a controller and projector such as any of those shown in FIGS. 2A-2C, 3, 4, 5, and 6. The method 700 begins at step 705, in which a data file corresponding to the three-dimensional part is received. In some implementations, this step can be performed by a controller such as the controller 215 shown in FIG. 2B. The file can be any type of computer aided design file that specifies the architecture of the part to be produced.

[0064] At step 710, a plurality of layers are generated based on the data file corresponding to the three-dimensional part. In some implementations, this step can be performed by a layer generating module such as the layer generating module 225 shown in FIG. 2B. For example, the layer generating module can be configured to produce a set of layers based on the architecture of the part represented by the data file received at step 705. In some implementations, the layer generating module can create a set of layers of the part by dividing the part into slices each having a thickness equal to a desired thickness for each layer. The layer generating module can determine the dimensions for each layer, as well as the position of each layer within the overall part.

[0065] The method 700 includes generating images corresponding to a plurality of regions for each layer (step 715). In some implementations, this step can be performed by a layer processing module such as the layer processing module 230 shown in FIG. 2B. The layer processing module can receive information corresponding to each layer generated at step 710. For each layer, the layer processing module can generate a set of images that should be output by the light source for the various regions of the build area of the device. Thus, in implementations in which the build area includes four regions (e.g., as illustrated in FIGS. 2A, 2C, 3, 5, and 6), the layer processing module can generate four images for each layer. In implementations in which the build area is divided into two regions (e.g., as illustrated in FIG. 4), the layer processing module can generate two images for each layer. Depending on this configuration of the projector included within the system, the layer processing module can be configured to select an orientation and a rotation for each image, such that the image can be correctly positioned within each region of the build area. For example, the layer processing module can generate the images in a manner that accounts for reflections of the images that occur as the image is reflected by the dynamic mirror array.

[0066] The method 700 includes raising the build plate to a predetermined height for the next layer (step 720). In some implementations, this step can be performed by a build plate driver such as the build plate driver 243 shown in FIG. 2B. For the first layer of the part, the predetermined height can be selected such that a surface of the build plate is positioned within a reservoir of precursor material such as the reservoir 107 shown in FIG. 1. For subsequent layers of the part, the predetermined height can be selected such that the surface of the most recent layer is positioned within the reservoir, so that the next layer can be formed on the previous layer.

[0067] The method 700 includes positioning the mirror array for construction of the next region of the current layer of the part (step 725). In some implementations, this step can be performed by a mirror array driver such as the mirror array driver 235 shown in FIG. 2B. As described above, dynamic mirror arrays can be have one or more positions for one or more movable mirrors that correspond to respective regions of a build area of an additive

manufacturing system. The mirror array driver can cause the mirrors to move into their respective positions for the next region of the current layer under construction. Then, at step 730, the method 700 includes activating the light source to consolidate the precursor material within the selected region of the current layer. In some implementations, this can be performed by a light source driver such as the light source driver 240 shown in FIG. 2B. Generally, the light source driver can cause the light source to output the image (generated at step 715) corresponding to the selected region.

[0068] The method 700 then proceeds to decision block 735, in which it is determined whether there are additional regions that have not yet been consolidated in the current layer. If there are, the method 700 returns to step 725, in which the mirror array driver positions the mirror array for the next region of the current layer. The light source driver then causes the light source to project the image for that region at step 730 to consolidate the material within that region. Thus, the decision block 735 causes the method 700 to loop until every region of the current layer has been consolidated.

[0069] The method 700 then proceeds to decision block 740, in which it is determined whether there are additional layers for the three-dimensional part under construction. If there are, the method 700 returns to step 720, in which the build plate driver causes the build plate to be raised to a predetermined height for the next layer. Generally, the build plate driver can achieve this by commanding the build plate to be raised by a distance equal to the thickness of a single layer relative to its previous height. The method then iterates through steps 725, 730, and 735 as described above until there are no additional regions to consolidate in the current layer. After all of the layers for the part have been constructed, the method ends at step 745.

[0070] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

[0071] Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation.

Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable sub combination.

Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub combination or variation of a subcombination.

[0072] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Claims

CLAIMS What is claimed is:

1. A projector for use in a three-dimensional printing system, the projector comprising:

a stationary light source producing an image within a projection area;

a first mirror moveable to a plurality of positions in the projection area and, for each of the plurality of positions, producing a respective reflected image from the image; and

a second mirror producing a respective second reflected image from each of the reflected images, each second reflected image corresponding to a respective portion of a planar build area of the three-dimensional printing system, the plurality of second reflected images encompassing an entirety of the planar build area.

2. The projector of claim 1, wherein the first mirror is configured to rotate to two positions.

3. The projector of claim 2, wherein the second mirror is stationary, and further comprising a third stationary mirror, wherein the second mirror and the third mirror are each configured to produce a respective one of the plurality of second reflected images.

4. The projector of claim 2, wherein the light source is configured to produce the projected image by emitting light in a direction substantially parallel to the build area.

5. The projector of claim 1, wherein the first mirror is configured to rotate to four positions.

6. The projector of claim 5, wherein:

the light source produces the projected image by emitting light in a direction

perpendicular to the build area; and

the second mirror is coupled to the first mirror such that the first mirror and the second mirror rotate together.

7. The projector of claim 1, further comprising actuator configured to rotate one of the first mirror or the second mirror.

8. The projector of claim 7, further comprising a control system configured to:

receive information defining a three-dimensional model to be built by the three- dimensional printing system;

generate a plurality of layers of the model each corresponding to a respective cross- sectional portion of the model;

for each layer, generate a plurality of subsections of the layer each corresponding to one of the portions of the build area; and

control the light source and the actuator to project images corresponding to the subsections in their respective portions of the build area.

9. A projector for use in a three-dimensional printing system, the projector comprising:

a stationary light source producing an image within a projection area;

a first mirror having a surface positioned within the projection area to produce a reflected image from the image; a second mirror movable to a plurality of positions and, for each of the plurality of positions producing a respective second reflected image from the reflected image; and

a third mirror producing a respective plurality of third reflected images from each second reflected image, each third reflected image corresponding to a respective portion of a planar build area of the three-dimensional printing system, the plurality of third reflected images encompassing an entirety of the planar build area.

10. The projector of claim 9, wherein the second mirror is configured to rotate to four positions.

11. The projector of claim 10, wherein:

the light source produces the projected image by emitting light in a direction parallel to the build area; and

the third mirror is coupled to the second mirror such that the second mirror and the third mirror rotate together.

11. The projector of claim 10, wherein:

the third mirror is one mirror of a first pair of mirrors, and further comprising a second pair of mirrors, each pair of mirrors configured to produce a respective one of the plurality of third reflected images.

12. The projector of claim 9, wherein the first mirror and the third mirror are stationary.

13. The projector of claim 9, further comprising actuator configured to rotate the second mirror.

14. The projector of claim 13, further comprising a control system configured to:

15. A method for fabricating a three-dimensional object, the method comprising:

receiving, by a controller, information defining a three-dimensional model of the three- dimensional object;

generating, by the controller, a layer of the model corresponding to a respective cross- sectional portion of the model;

generating, by the controller, a plurality of subsections of the layer each corresponding to a respective portion of a planar build area;

positioning, by the controller, a build plate at a predetermined height corresponding to the build area within a reservoir containing a precursor material;

for each portion of the planar build area: moving, by the controller, a first mirror of a plurality of mirrors into a position corresponding to the portion of the planar build area; and

activating, by the controller, a light source to project an image in the portion of the planar build area to solidify the precursor material, the image corresponding to the respective subsection of the layer.

16. The method of claim 15, wherein the first mirror is moveable to a plurality of positions in a projection area of the light source, wherein the plurality of mirrors further comprises a second mirror configured to receive a reflected image from the first mirror and to produce the image corresponding to the respective subsection of the layer, and wherein moving the first mirror comprises rotating the first mirror within the projection area of the light source.

17. The method of claim 16, wherein the first mirror and the second mirror are coupled with one another, the method further comprising rotating the first mirror and the second mirror together.

18. The method of claim 15, wherein the plurality of mirrors comprises a second stationary mirror positioned within a projection area of the light source, wherein the first mirror is configured to receive a reflected image from the second mirror and to produce the image corresponding to the respective subsection of the layer, wherein moving the first mirror comprises rotating the first mirror.

19. The method of claim 15, wherein moving the first mirror comprises driving, by the controller, an actuator coupled with the first mirror to rotate the first mirror into the position corresponding to the portion of the planar build area.

20. The method of claim 15, further comprising:

generating, by the controller, a plurality of additional layers of the model corresponding to respective additional cross-sectional portions of the model;

generating, by the controller, a plurality of subsections of each layer, each subsection corresponding to a respective portion of the planar build area.