Multi-material digital light processing printing system and method using centrifugal and ultrasonic-assisted washing

Abstract

Methods and systems for fabricating three-dimensional multi-material objects using a three-dimensional printer are disclosed. In embodiments, a three-dimensional printer includes a rotary build stage, a plurality of vats holding different resins, a projection system configured to project an image to cause resin to cure on the rotary build stage, and an ultrasonic washer comprising a washing chamber containing a wash medium and an ultrasound generator. In embodiments, a first resin in a first vat cures in a first layer of a three-dimensional object upon the rotary build stage, before being removed and placed in the washing chamber, where the three-dimensional object is rotated while exposed to acoustic waves in order to remove waste residue. In embodiments, the three-dimensional object is then placed in a second vat to enable a second resin to cure in a second layer, before being similarly washed, enabling efficient creation of three-dimensional multi-material objects.

Description

Attorney Docket # 00495-0031 (B2025-011)MULTI-MATERIAL DIGITAL LIGHT PROCESSING PRINTING SYSTEM AND METHOD USING CENTRIFUGAL AND ULTRASONIC-ASSISTED WASHING IN AN IMMISCIBLE, LIGHTER LIQUIDREFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 821,545, filed June 11, 2025, and entitled “MULTI-MATERIAL DIGITAL LIGHT PROCESSING PRINTING SYSTEM AND METHOD USING CENTRIFUGAL- AND ULTRASONIC-ASSISTED WASHING IN AN IMMISCIBLE, LIGHTER LIQUID,” and U.S. Provisional Patent Application Serial No. 63 / 702,367, filed October 2. 2024, and entitled “LARGE AREA, HIGH RESOLUTION PROJECTION LITHOGRAPHY SYSTEM WITH MOVING OPTICS” the entire contents of which are hereby incorporated by reference herein.GOVERNMENT SUPPORT CLAUSE

[0002] The invention was made with government support under Grant Number 2309828 awarded by the National Science Foundation. The government has certain rights in the invention.FIELD

[0003] The present invention generally relates to large area, high-resolution, projection stereolithography and improvements in 3D printing techniques for multi-material objects.BACKGROUND

[0004] Projection stereolithography (PSL), also known as digital light processing (DLP) 3D printing, is a technique that uses a digital light projector to selectively cure liquid resin into solid material, layer by layer. By carefully controlling the energy and pattern of light. PSL allows for the creation of complex three-dimensional structures with precise geometries. This technology, while useful, including for the fabrication of lightweight structural materials and functional devices [1, 2], is at present constrained to small-scale production. This limitation stems primarily from the resolution restrictions imposed by the light engine used in the system, which affects the minimum feature size and overall scalability of the objects produced [3, 4],

[0005] Others have attempted to devised methods to extend the capabilities of PSL for larger scale applications, but all have failed to achieve high-resolution printing at a large scale. For example, Lee et al. (2015) [5] proposed a tiling process that projected small tiles sequentially across the resin surface. Similarly, Emami et al. (2014) [6] and Meenakshi sundaram et al. (2019) [7] enhanced the scale by mounting the projection unit on x-14925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) y stages, allowing it to move continuously during the exposure process. Zheng et al. (2016) [8] employed a fixed projection system coupled with x-y scanning galvo-mirrors to address both resolution and scalability. Despite these attempts, no existing PSL system has successfully demonstrated the ability to 3D print complex structures larger than 50 cm with high precision. This restriction remains a significant bottleneck in the efficient production of commercial products, metamaterials, and large-scale antennas [9, 10], which demand both substantial sizes and detailed features.

[0006] Additionally, some 3D printing techniques use what is known as multi-material vat photopolymerization (VPP). Advancements in VPP have enabled the fabrication of complex functional structures, but challenges in material switching and selective metallization continue to hinder progress in fabricating 3D electronics using VPP. Conventional multi-material VPP systems rely on multiple vat / resin switching processes, ty pically consisting of three steps: (1) switching to a different vat / material, (2) removing resin residue from the printed structure, and (3) drying the diluted material [47. 48],

[0007] Several approaches exist to address material residue removal. One bottom-up multi- vat system employs physical brush cleaning, ultrasound solvent cleaning, and air-fan drying before switching vats

[0025] , while another sprays ethanol and blows compressed air

[0019] , Single- vat multi-material VPP systems often utilize dynamic fluid delivery combined with organic solvents for cleansing prior to material switching [1, 2. 18. 49, 50, 51, 52], More recent systems leverage centrifugal force to remove resin residue, eliminating the need for a separate drying step

[0053] ,

[0008] These approaches have significant limitations. The use of solvents to dissolve resin residue can weaken interfacial strength by breaking unreacted oligomers

[0051] and prolonged ethanol exposure can lead to surface cracking, compromising post-metallization selectivity. Additionally, unoptimized angular speeds may damage delicate structures

[0053] , Furthermore, in complex geometries with microscale openings, centrifugal force alone may not be sufficient to overcome surface tension and remove liquid residues.

[0009] What is needed is a way to enable projection stereolithography to print large-scale, complex 3D structures with high precision and to improve techniques to remove material residue during the 3D printing process.SUMMARY

[0010] In view of the above, it is an object of the present disclosure to provide a technological solution to address the long felt need and technological challenges faced in24925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) conventional stereolithography systems by providing a novel scanning projection stereolithography (SPSL) system. It has been demonstrated that the novel SPSL. which integrates a scanning optical system, expands the printing scale beyond 50 cm while maintaining a high-resolution of at least 50 pm, concurrently reducing printing time through optimized scan paths and motion speeds.

[0011] An advantage of the present disclosure is to enhance the production of architected materials. These materials, also known as engineered or designer materials, are designed to exhibit specific mechanical [8, 11-14], thermal

[0015] , acoustic

[0016] , or electromagnetic properties

[0017] that can be finely tuned through the geometry' of their internal structure rather than their chemical composition. The enhanced capabilities of the disclosed SPSL system enables the creation of such intricate geometries and architectures on a scale previously unattainable, paving the way for revolutionary applications in diverse domains from electronics

[0018] to robotic engineering

[0019] ,

[0012] The resolution and printing area of embodiments of the present invention are, combined, superior to those other existing additive manufacturing methods

[0031] such as fused deposition modeling (FDM) [32-34], material jetting [35-37], selective laser sintering (SLS) [38, 39], regular projection-based stereolithography [11, 40-42], and two-photon polymerization (TPP) [43-45], Embodiments of the present disclosure both achieve a high resolution of 50 pm while also supporting large printing areas up to tens of centimeters. This combination of high precision and extensive printing area is particularly beneficial for industrial applications and various other fields, offering adaptability and scalability' that many other methods cannot match.

[0013] In further view of the above, it is a still further object of the present invention to provide a technological solution to address the long felt need and technological challenges faced in conventional stereolithography systems employing VPP by providing a novel multimaterial VPP method that utilizes centrifugal-assisted and ultrasonic assisted washing in an immiscible, lighter-than-resin liquid to remove resin residue, as disclosed in exemplary embodiments herein.

[0014] In exemplary embodiments, a scanning projection system includes: (a) an illumination device, configured to emit light rays corresponding to an initial image; (b) a collimating lens configured to propagate the light rays emitted from the illumination device to form aligned light rays; (c) a first movable reflection mirror configured to reflect the aligned light rays to form reflected aligned light rays; (d) a movable focusing lens configured to34925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) propagate reflected aligned light rays to form an intermediate image based on the reflected aligned light rays; (e) a second movable reflection mirror configured to reflect the intermediate image to form a reflected intermediate image; and (f) a movable projection lens configured to receive the reflected intermediate image and project a final image onto curable resin located on a projection plane. In embodiments, the resolution of the final image is adjustable by moving the movable projection lens. In embodiments, the curable resin, after exposure to the final image, develops to generate a portion of a 3D structure.

[0015] In embodiments, the illumination device is a light engine including a digital micromirror device.

[0016] In embodiments, the scanning projection system further includes: (g) a beam splitter between the collimating lens and the first movable reflection mirror, wherein the beam splitter is configured to receive the aligned light rays and form split aligned light rays; and (h) a camera configured to detect light intensity of the split aligned light rays corresponding to the first image. In embodiments, a second initial image is determined based on the detected light intensity. In embodiments, the illumination device is configured to emit second light rays corresponding to a second initial image.

[0017] In embodiments, the focusing lens is a tube lens.

[0018] In embodiments, the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are mounted on one or more linear motion stages.

[0019] In embodiments, the first movable reflection mirror is mounted on a first linear motion stage, and movable focusing lens, the second movable reflection mirror and the movable projection lens are mounted on a second linear motion stage. In embodiments, the second linear motion stage is perpendicular to the first linear motion stage. In embodiments, the second linear motion stage is mounted on the first linear motion stage.

[0020] In embodiments, the location of the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are controlled by a controller.

[0021] In embodiments, the projection pixel resolution of the final image is between 10 micrometers and 100 micrometers.

[0022] In exemplary embodiments, a method of 3D printing includes: (a) emitting, by an illumination device, light rays corresponding to an initial image; (b) propagating the light rays emitted from the illumination device through the collimating lens to form aligned light rays;44925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)(c) reflecting, by a first movable reflection mirror, the aligned light rays to form reflected aligned light rays; (d) propagating the reflect aligned light rays through a movable focusing lens to form an intermediate image based on the reflected aligned light rays; (e) reflecting, by a second movable reflection mirror, the intermediate image to form a reflected intermediate image; (f) projecting, by a movable projection lens, a final image onto curable resin located on a projection plane; and (g) developing a curable resin to form a portion of a 3D object after exposure to the final image. In embodiments, the projection pixel resolution of the final image is adjustable by moving the movable projection lens.

[0023] In embodiments, the illumination device is a light engine including a digital micromirror device.

[0024] In embodiments, between steps (b) and (c) the method further includes : (h) splitting, by a beam splitter between the collimating lens and the first movable reflection mirror, the aligned light rays to form second aligned light rays corresponding to the first image; (i) detecting, by the beam a camera, light intensity of the second aligned light rays; (j) determining, by a first processing device, a second initial image based on the detected light intensity; and (k) emitting, by the illumination device, second light rays corresponding to the second initial image.

[0025] In embodiments, the focusing lens is a tube lens.

[0026] In embodiments, the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are mounted on one or more linear motion stages.

[0027] In embodiments, the first movable reflection mirror is mounted on a first linear motion stage, and the movable focusing lens, the second movable reflection mirror and the movable projection lens are mounted on a second linear motion stage. In embodiments, the second linear motion stage is perpendicular to the first linear motion stage. In embodiments, the second linear motion stage is mounted on the first linear motion stage.

[0028] In embodiments, the location of the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are controlled by a controller.

[0029] In embodiments, the projection pixel resolution of the final image is between 10 micrometers and 100 micrometers.

[0030] In exemplary embodiments, a method of 3D printing includes: (a) exposing a first resin in a first vat to light so as to cure a first layer of a three-dimensional object upon a rotary54925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) build stage; (b) removing the three-dimensional object from the first vat while still attached to the rotary’ build stage; (c) placing the three-dimensional object in a wash medium within a washing chamber while the three-dimensional object is still attached to the rotary build stage; (d) rotating the three-dimensional object within the wash medium; (e) exposing the three- dimensional object to ultrasonic waves within the wash medium generated by an ultrasonic generator; (I) removing the three-dimensional object from the wash medium; (g) exposing a second resin in a second vat to light so as to cure a second layer of the three-dimensional object upon the rotary build stage; (h) removing the three-dimensional object from the second vat while still attached to the rotary' build stage; (i) placing the three-dimensional object in the wash medium within the washing chamber while the three-dimensional object is still attached to the rotary’ build stage; (j) rotating the three-dimensional object within the wash medium; (k) exposing the three-dimensional object to ultrasonic waves within the wash medium generated by an ultrasonic generator; and (1) removing the three-dimensional object from the wash medium.

[0031] In embodiments, the wash medium includes hexane. In embodiments, the wash medium includes water.

[0032] In embodiments, the three-dimensional object completes a full rotation within the wash medium.

[0033] In embodiments, the rotational speed of the rotary build stage is between 100 and 1000 rotations per minute.

[0034] In embodiments, the frequency of the ultrasonic waves generated by the ultrasonic generator is 40,000 Hz.

[0035] In embodiments, the first resin and the second resin are different resins.

[0036] In embodiments, the three-dimensional object is a multi-material object.

[0037] In embodiments, method further includes: (m) exposing the first resin in the first vat to light so as to cure a third layer of the three-dimensional object upon a rotary build stage.

[0038] In embodiments, method further includes: (m) exposing the second resin in the second vat to light so as to cure a third layer of the three-dimensional obj ect upon a rotary’ build stage.

[0039] In embodiments, the method further includes: (m) exposing a third resin in a third vat to light so as to cure a third layer of the three-dimensional object upon a rotary build stage.

[0040] In exemplary embodiments, a 3D printing system includes: (a) a rotary' build stage; (b) a plurality of vats including a first vat and a second vat. each configured to hold a respective64925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) resin; (c) a projection system configured to project an image so as to cause resin to cure; (d) a first washing chamber configured to hold a first wash medium; and (e) an ultrasound generator configured to transmit ultrasonic waves within the washing chamber when filled with the wash medium.

[0041] In embodiments, the 3D printing system further includes an elevator for raising and lowering the rotary build stage.

[0042] In embodiments, the 3D printing system further includes one or more motion stages for moving the rotary build stage along a two-dimensional plane.

[0043] In embodiments, the plurality of vats includes a third vat.

[0044] In embodiments, the projection system includes an ultraviolet projector and one or more optical components.

[0045] In embodiments, the one or more optical components include a mirror for reflecting light from the ultraviolet projector towards one or more of the plurality of vats.

[0046] In embodiments, the 3D printing system further includes one or more motion stages configured to move one or more of the one or more optical components along a two- dimensional plane. In embodiments, the 3D printing system further includes one or more motion stages configured to move the ultraviolet projector along a two-dimensional plane.

[0047] In embodiments, the first wash medium includes hexane. In embodiments, the first wash medium includes water.

[0048] In embodiments, the 3D printing system further includes a second washing chamber configured to hold a second wash medium. In embodiments, the second wash medium includes hexane. In embodiments, the second wash medium includes water.

[0049] In embodiments, the 3D printing system further includes a vat platform, wherein each of the plurality of vats and the first washing chamber sit atop the vat platform. In embodiments, the 3D printing system further includes one or more motion stages configured to move the vat platform along a two-dimensional plane. In embodiments, the 3D printing system further includes one or more elevators configured to raise and lower the vat platform.

[0050] In embodiments, the 3D printing system further includes at least one rotational stage configured to rotate the vat platform.

[0051] Other features and advantages of the present invention will become readily apparent from the following detailed description and the accompanying draw ings.BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The above and related objects, features and advantages of the present invention will74925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) be more fully understood by reference to the following, detailed description of the preferred, albeit illustrative, embodiment of the present invention when taken in conjunction with the accompanying figures, wherein:

[0053] FIG. 1A is a schematic drawing illustrating a 3D printing system incorporating a scanning projection system in accordance with exemplar}' embodiments of the present invention;

[0054] FIG. IB is a schematic drawing illustrating a scanning projection system in accordance with exemplary embodiments of the present invention;

[0055] FIG. 1 C is a top-down photograph of a 3D printing system incorporating a scanning projection system in accordance with exemplary embodiments of the present invention;

[0056] FIG. ID is a side view photograph of a scanning projection system incorporated in a 3D printing system in a accordance with exemplary' embodiments of the present invention;

[0057] FIG. 2A is a schematic drawing illustrating a scanning projection system (e.g., scanning projection system 201) in accordance with exemplary embodiments of the present invention;

[0058] FIG. 2B provides a projection image captured by a CCD camera in accordance with embodiments of the present invention;

[0059] FIG. 2C illustrates a gray mask process used to mitigate non-uniform light intensity in accordance with embodiments of the present invention;

[0060] FIG. 2D is a set of photographs depicting a pyramid microstructure array fabricated in accordance with embodiments of the present invention;

[0061] FIG. 3 A is a diagram showing a design of a vase which was divided into layers, images, and subsections of images in accordance with exemplary' embodiments of the present invention;

[0062] FIG. 3B provides a schematic drawing illustrating the light intensity between neighboring sections of an image in accordance with exemplary embodiments of the present invention;

[0063] FIG. 3C provides curing depth measurements of the vase depicted in FIG. 3A in accordance with embodiments of the present invention;

[0064] FIG. 4A provides an illustration of an optimized scan path in accordance with exemplary embodiments of the present invention;

[0065] FIG. 4B is a chart comparing conventional scanning methods with a scanning method performed in accordance with exemplary embodiments of the present inventions;84925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0066] FIG. 4C is a chart showing the motion profile of the scanning stage in accordance with exemplary embodiments of the present invention;

[0067] FIG. 4D is a chart showing the estimated printing time with varying maximum speed and acceleration in accordance with exemplary7embodiments of the present invention;

[0068] FIG. 4E is a 3D map illustrating showing the estimated printing time with varying maximum speed and acceleration in accordance with exemplary embodiments of the present invention;

[0069] FIG. 5A is a photograph of large-scale hierarchical CFRP truss-lattice materials fabricated in accordance with exemplary embodiments of the present invention;

[0070] FIG. 5B is a photograph of CFRP plate-lattice materials fabricated in accordance with exemplary' embodiments of the present invention;

[0071] FIG. 5C is a photograph of large-size high-resolution CFRP Voronoi vase fabricated in accordance with exemplary embodiments of the present invention;

[0072] FIG. 6 A illustrates a photograph of a maize stem under a microscope, as w ell as a lattice replicating the tissue structure of the maize stem;

[0073] FIG. 6B illustrates a schematic of a conventional car bar energy' absorber 604 attached to car 606;

[0074] FIG. 6C is stress-strain chart for three different lattice designs;

[0075] FIG. 6D shows the evaluation of multiple designs with different configurations depending on the gradient value and plotted their corresponding figure of merit (FOM) values;

[0076] FIG. 6E is a design of a lightweight bumper energy' absorber featuring gradient wall thickness and unit cell sizes, capable of being printed in accordance with exemplary embodiments of the present invention;

[0077] FIG. 7A is an image of a sliced layer of the energy absorber shown in FIG. 6E segmented into sub-images in accordance with exemplary embodiments of the present invention;

[0078] FIG. 7B is a photograph showing two parts of the energy’ absorber design shown in FIG. 6E which was printed in accordance with exemplary embodiments of the present invention;

[0079] FIG. 7C is a photograph of a large-scale car bumper energy' absorber corresponding to the design shown in FIG. 6E as fabricated in accordance with exemplary embodiments of the present invention;94925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0080] FIG. 8A is a schematic drawing of a processing system and control system of a 3D printing system in accordance with embodiments of the present invention;

[0081] FIG. 8B illustrates an example of a processing and control schematic of the printing system, comprising a processing system, a control system, and mechanical system;

[0082] FIG. 9 is a flow chart depicting a process for 3D printing an object in accordance with exemplary embodiments of the present invention;

[0083] FIG. 10 is a schematic of a multi-material digital light processing system incorporating a centrifugal-assisted and ultrasonic-assisted washer in accordance with exemplary embodiments of the present invention;

[0084] FIG. 10A is a schematic of a centrifugal-assisted and ultrasonic-assisted washer in accordance with exemplary embodiments of the present invention;

[0085] FIGs. 11A-11C are photographs of aspects of a multi-material digital light processing system incorporating a centrifugal-assisted and ultrasonic-assisted washer in accordance with exemplary embodiments of the present invention;

[0086] FIG. 12 is a flow chart depicting a process for 3D printing a three-dimensional multi -material obj ect in accordance with exemplary embodiments of the present invention; and

[0087] FIGs. 13A-13D are photographs of three-dimensional objects fabricated in accordance with exemplary embodiments of the present invention.DETAILED DESCRIPTION

[0088] The present invention generally relates to large area, high-resolution, projection stereolithography and improvements in 3D printing techniques for multi-material objects.Large Area, High Resolution Projection Stereolithography

[0089] FIG. 1A is a schematic drawing illustrating a 3D printing system incorporating a scanning projection system in accordance with exemplary embodiments of the present invention. FIG. IB is a schematic drawing illustrating a scanning projection system in accordance with exemplary embodiments of the present invention.

[0090] In exemplary' embodiments, the scanning projection system (e.g., scanning projection system 100 or 101) includes an illumination device (e.g., light engine 102) configured to emit light rays corresponding to an initial image, a collimating lens (e.g., collimating lens 104) configured to propagate the light rays emitted from the illumination device to form aligned light rays (e.g., parallel light 106), a first movable reflection mirror (e.g.,104925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) reflection mirror 108a) configured to reflect the aligned light rays to form reflected aligned light rays, a movable focusing lens (e.g., focusing lens 110) configured to propagate reflected aligned light rays to form an intermediate image based on the reflected aligned light rays, a second movable reflection mirror (e.g., reflection mirror 108b) configured to reflect the intermediate image to form a reflected intermediate image, and a movable projection lens (e.g., reflection lens 112) configured to receive the reflected intermediate image and project a final image (e.g., final image 114) onto curable resin (e.g.. resin 118) located on a projection plane (e.g., projection plane 1 16). In embodiments, the scanning projection system is included as part of a 3D printing system (e.g., 3D printing system 100).

[0091] In embodiments, the illumination device is a light engine comprising a digital micromirror device (e.g., DMD 103). In embodiments, the illumination device is a high resolution UV projector (e.g., a 4k DLP (XRP) projection, having a resolution of 3840x2160, to give an example).

[0092] In embodiments, the movable focusing lens is a tube lens.

[0093] In embodiments, the final image has a projection pixel resolution between 10 micrometers and 5100 micrometers. The projection area of the final image, in embodiments, corresponds to 38.4x21.6 mm2and 192x108 mm2, respectively.

[0094] In embodiments, the curable resin is located in a vat / tank (e.g., vat 120) which is above the scanning projecting system. In embodiments, the resin tank's bottom is made of a transparent, non-stick Teflon film (FEP), which is affixed to a UV-grade fused silica window to provide a rigid structure.

[0095] In embodiments, the curable resin includes a mixture of an UV ultraviolet (UV) curable matrix (e.g.. Rigid 10k, Formlabs, Inc.; Any cubic Tough resin, to give an example) with milled short carbon fibers (e.g., 7 pm in diameter, ~70 pm mean length, E&L Enterprises, Inc., to give an example) and silica nanoparticles (e.g., TS 720, Cabot, Inc., to give an example).

[0096] In embodiments, the curable resin, after exposure to one or more final images (e.g., the projected images, and / or additional projected images), develops to generate a portion of a 3D structure (e.g., a portion of 3D structure 124, attached to printing platform 122). In embodiments, the portion has a feature size of 20 micrometers or smaller. In embodiments, the portion has a feature size between 20 and 50 micrometers. In embodiments, the 3D structure has a plurality of feature sizes. In embodiments, each of the plurality of feature sizes is between 20 micrometers and 2.5 millimeters. In embodiments, each of the plurality of feature sizes is between 20 micrometers and 50 centimeters.114925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0097] FIG. 1 C is a top-down photograph of a 3D printing system incorporating a scanning projection system in accordance with exemplary embodiments of the present invention. FIG. ID is a side view photograph of a scanning projection system incorporated in a 3D printing system in accordance with exemplary embodiments of the present invention.

[0098] The 3D printing system shown in FIG. 1C includes with a vat 120a (similar to vat 120). a printing platform 122a (similar to printing platform 122), having x-y dimensions of approximately 22 cm by 35 cm.

[0099] As shown in FIG. 1C, in embodiments, the printing platform is movable on z-axis, for example by z-axis elevator 126. In embodiments, the printing (or “build’') platform is mounted on an extrusion (e.g., an aluminum extrusion) and connected to translation stages (e.g., in the z-axis).

[0100] As shown in FIG. ID, the 3D printing system photographed also includes a light engine (e.g., light engine 102), scanning optics (such as a collimating lens, a first movable reflection mirror, a movable focusing lens, a second movable reflection mirror, and a movable projection lens) (e.g., scanning optics 124), and an x, and y, motion stage (e.g., motion stages 128a, 128b, respectively).

[0101] As shown in FIG. IB and ID, in embodiments, the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are mounted on one or more linear motion stages (e.g., x motion stage 128a and y motion stage 128b). In embodiments, the first movable reflection mirror is mounted on a first linear motion stage, and the movable focusing lens, the second movable reflection mirror and the movable projection lens are mounted on a second linear motion stage perpendicular to the first linear motion stage. In embodiments, the second linear motion stage is mounted on the first linear motion stage. In embodiments, the first movable reflection mirror, the movable focusing lens, the second movable reflection mirror and the movable projection lens are mounted on both the first and second linear motion stages perpendicular). In embodiments, the linear motion stages are precision translation stages.

[0102] In embodiments, adjustments of the projection area and resolution can be easily performed by tuning the position of the projection lens and projection plane, by changing the overall magnification ratio M =where d0is the distance between the projection lensand the intermediate image, and fc. ff and fpare the effective focal length of the collating lens, the focusing lens, and the projection lens, respectively. In embodiments, adjustments can be made by moving the projection lens and intermediate image, and / or adjusting one or more the124925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) effective focal length of the collating lens, the focusing lens, and the projection lens. An advantage of this flexible magnification ratio is that it makes it possible to adapt the printer to different 3D printing tasks with varying feature size requirements.

[0103] FIG. 2A is a schematic drawing illustrating a scanning projection system (e.g., scanning projection system 201) in accordance with exemplary embodiments of the present invention. Scanning projection system 201 includes DMD 103, collimating lens 104. first movable reflection mirror 108a (movable via X translation 240), movable focusing lens 110 (movable via Y translation 250), second movable reflection mirror 108b (movable via Y translation 112), and movable projection lens 112, all of which may play a similar role as in scanning projection system 201. As FIG. 2A depicts, in embodiments, the scanning projection system further includes a beam splitter (e.g., beam splitter 202) between the collimating lens and the first movable reflection mirror and a camera (e.g., CCD (charge-coupled device) camera 204. In embodiments, the beam splitter is configured to receive the aligned light rays and form split aligned light rays, such that the split aligned light rays are directed to the camera. In embodiments, the camera is configured to detect light intensity of the split aligned light rays corresponding to the first image. In embodiments, the camera is used to visualize the final projection image. In embodiments, the position of the elements of the optical system (e.g., of the first movable reflection mirror, the movable focusing lens, second movable reflection mirror, and movable projection lens) is adjusted to based on the visualization of the final projection image. An advantage of doing so is that it enables the optimization of the focus and alignment of the various elements of the optical system, as well as for correct non-uniformity of the image. For example, in embodiments, an image may be obtained by a computer connected to the camera, which is then compared with the initial image projected, for example, to determine if the image is properly being displayed. Continuing the example, in embodiments, based on the comparison, adjustments to the optical system may be made, including changing the location of one or more of the movable elements of the optical system (e.g., of the first movable reflection mirror, the movable focusing lens, second movable reflection mirror, and movable projection lens), and adjusting the focus of one or more of the lens, including the collimating lens, to give a couple of examples.

[0104] FIG. 8 A is a schematic drawing of a processing system and control system of the 3D printing system in accordance with embodiments of the present invention. In embodiments, the processing system includes a processing computer 800 (e.g.. a computer running a processing system such as Windows, Linux, or MacOS, to give a few examples) including a134925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) processor configured to execute one or processing system modules (e.g., processing system module(s) 802) on computer-readable memory (e.g., database(s) 804). The one or more processors may include processing circuitry capable of controlling operations and functionality of the interventional training distribution model. For purposes of the present disclosure, each module may include its own local memory', which may store program systems, program data, and / or one or more operating systems configured to perform the functions thereof. In embodiments, the memory may be a database or multiple databases. In embodiments, the memory may be a memory included in or operably connected to one or more processors of a computer system, such as a server in a network. In embodiments, the memory may be a cloud based storage system. In embodiments, the memory may be one or more of the above devices.

[0105] In embodiments, the process computer 800 may also include a display device (e.g., a monitor) and one or more input devices (e.g., mouse and keyboard, to give an example). The processing computer may also have an output device, such as a usb port, that enables the processing computer to be operably connected, and transmit information to, a three- dimensional printer or a control system associated with the three-dimensional printer. Additionally, or alternatively, the computer system may be configured to store, for example via external memory like a USB stick, information, which can then be removed and plugged into a control system associated with the three-dimensional printer for execution.

[0106] In embodiments, the processing system module(s) 802 are configured to process a 3D model representing an object to be 3D-printed by slicing the 3D model into 2D images, and then slicing the 2D-images into sub-image associated with coordinates. In embodiments, the 3D model is sliced into 2D images (which may represent layers of the 3D model) using the processing system module(s) (e.g., using Netfabb or nTopology. to give a couple of examples). In embodiments, the sliced 2D images are then processed using the processing system module(s) (e.g., using Matlab, to give an example) to segment the sliced 2D-images into sub-images. In embodiments, the processing system module(s) use an optimization code for scanning paths to identify void sub-images within each layer, optimize the scanning paths, and generate a file with the coordinate location of the individual images (e.g.. an x, y, z, coordinate location for an image to be projected onto resin).

[0107] In embodiments, the 3D model, 2D images, sub-images, and respective coordinate locations used for printing are stored in the one or more database(s) 804.

[0108] In embodiments, the printing area of the system for each single projection is adjustable to match the resolution and size requirements of the design. In embodiments, for144925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) less critical accuracy requirements, increasing the projection area can reduce the overall printing time. For example, in the case of an energy absorber (discussed further below), which has a minimal wall thickness of 1 mm, each layer is divided into 3x5 sub-images, totaling a projection area of 22.4x28 cm2. In embodiments, the one or more processing modules are configured to adapt to various image sizes and segment them according to predefined requirements.

[0109] In embodiments, the processing computer (800) is operably connected to a camera (e.g., CCD camera 204) which is configured to detect light intensity of the aligned light rays (e.g., the split aligned light rays). In embodiments, based on the detected light intensity7, the processing system may generate a second initial image to be used by the light engine. For example, in embodiments, the processing system modules may be used to generate a measured light intensity profile, fitted light intensity profile based on the measured light intensity profile, gray mask based on the fitted light intensity profile, and a second initial image (e.g., a masked projection image) based on the gray mask and the initial image. In embodiments, the control system module is configured to provide the second initial image to the light engine 102, which is configured to emit the second initial image.

[0110] In embodiments, the scanning path may be optimized so as to reduce the printing time according to the formula. T = N * (Tr+ kTe+ (k — l)Tm) , where T quantifies the overall printing time where N is the number of layers. Tris the recoating time, Teis the exposure time, and Tmis the stage moving time. In embodiments, Tm, is calculated using the formula: Tm= “ + “■ where d is the moving distance, V is the maximum moving speed, and a is the acceleration speed.

[0111] In embodiments, the scan path is optimized to minimize movement time. This problem corresponds to the classical optimization problem known as the ‘Traveling Salesman Problem” (TSP), for which no general solution exists (starting from a fixed initial point, visiting each necessary' sub-image exactly once without returning to the start). In embodiments, the scan path is optimized by evolving a population of routes through selection, crossover, and mutation to minimize the total travel distance. In embodiments, identifying the sub-images with projection patterns and generating a scanning route file for the stage motion control is performed as follows:154925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) stage_speeds move length initial_position# Process each layer from start_layer to end_layer for each layer from start_layer to end_layer do:# Identify sub-images with projection patterns sub_image_flags = detect_sub_images(current_layer)# Calculate the number of necessary scanning locations num locations = count_sub_images(sub_image_flags) + 1# Identify coordinates of each sub-image[x_coords, y_coords] = get_sub_image_coordinates(sub_image_flags) add_initial_position(x_coords, y_coords, initial_position)# Calculate movement time between each pair of points for each pair of points (i, j) do: distance_x, distance^' = calculate_distance(x_coords[i], y_coords|j]) time_move = calculate_time(distance_x, distance_y. stage speeds) update_time_matrix(i, j, time_move)# Optimize the scan path using a genetic algorithm config = selup genetic algorithmtx coords. y_coords, time_matrix) result = run_genetic_algorithm(config) optimal_path = result. optimal_route optimal time = result, minimum time# Update starting position for the next layer initial_position = update_starting_position(optimal_path, x_coords, y_coords)# Store the scanning coordinates and times store_scan_coordinates(optimal_path. offsets)164925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011)

[0112] In embodiments, the x motion stage and y motion stage move simultaneously when moving from one location to another. In embodiments, the optimized path differs depending on the speed of the linear stages. In embodiments, unlike a conventional traveling salesman problem, where the optimized path needs to be connected at both the beginning and end, the scanning method has a fixed starting point and an open endpoint. In embodiments, the endpoint in one layer becomes the starting point for another layer. An example of an optimized scanning path is given by FIG. 4A, discussed in further detail below.

[0113] Still referring to FIG. 8 A, in embodiments, the control system includes one or more control computers (e.g., PC(s) 800) comprising one or more processors configured to execute one or more control system modules (e g., control system module(s) 806) stored on computer- readable memory (e.g., database(s) 804). The one or more processors may include processing circuitry capable of controlling operations and functionality of the interventional training distribution model. For purposes of the present disclosure, each module may include its own local memory, which may store program systems, program data, and / or one or more operating systems configured to perform the functions thereof. In embodiments, the memory may be a database or multiple databases. In embodiments, the memory may be a memory' included in or operably connected to one or more processors of a computer system, such as a server in a network. In embodiments, the memory may be a cloud based storage system. In embodiments, the memory may be one or more of the above devices.

[0114] In embodiments, the control computer is operably connected to one or more electronic controllers (e.g., controller(s) 808, which may include a “Duet 2" electronic microcontroller and an “Arduino” microcontroller, to give a couple of examples) and the light engine / projector (e.g., light engine / projector 102).

[0115] In embodiments, as depicted in FIG. 8 A, the control computer is the same as the processing computer. In embodiments, the control computer is a different computer than the processing computer.

[0116] In embodiments, the one or more electronic controllers may be operably connected a power supply (e.g., power supply 810) which supplies power to the electronic controllers. In embodiments, the one or more electronic controllers receive signals from limit switches (e.g., limit switches 812) of the motion stages (e.g., motion stages 128a, 128b). In embodiments, the one or more electronic controllers provides signals (e.g., motion control signals, aperture control signals) to the motion stages (e.g., motion stages 128a, 128b) and a shutter servo (e.g.,174925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) shuter servo 814). In embodiments, the location of the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are controlled by a controller.

[0117] In embodiments, the scanning projection system (e.g., scanning projection system similar to 100 or 101) further includes a second illumination device (similar to light engine 102) configured to emit light rays corresponding to a third image corresponding to a different part of a 3D model than the initial image. In such embodiments, the scanning projection system further includes a second collimating lens (similar to collimating lens 104) configured to propagate the light rays emitted from the illumination device to form second aligned light rays (similar to parallel light 106), a third movable reflection mirror (similar to reflection mirror 108a) configured to reflect the second aligned light rays to form second reflected aligned light rays, a second movable focusing lens (similar to focusing lens 1 10) configured to propagate the second reflected aligned light rays to form a second intermediate image based on the second reflected aligned light rays, a fourth movable reflection mirror (similar to reflection mirror 108b) configured to reflect the second intermediate image to form a second reflected intermediate image, and a second movable projection lens (similar to reflection lens 112) configured to receive the second reflected intermediate image and project a second final image (similar to final image 114) onto the curable resin (e.g., resin 118) located on a projection plane (e.g., projection plane 116). In such embodiments, printing speed may be increased by enabling simultaneous curing of multiple areas.

[0118] FIG. 9 is a flow chart depicting a process for 3D printing an object in accordance with exemplary embodiments of the present invention.

[0119] In embodiments, the process includes step S900. At step S900 an illumination device emits light rays corresponding to an initial image. In embodiments, the initial image, as discussed herein, corresponds to a sub-section of layer of a 3D object (also referred to herein as a “sub-image”). In embodiments, the light rays are UV rays configured to cure resin in a vat. In embodiments, the process continues with step S902.

[0120] At step S902, the light rays from the illumination device are propagated through a collimating lens to form aligned light rays. In embodiments, the aligned light rays may be measured by a CCD camera, and used to generate a new initial image, and the process continued with S900 using the new initial image. For example, the light intensity throughout the initial image may be measured, and a grayscale mask applied to the initial image in order to generate the new initial image. In embodiments, the process continues with step S904.184925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0121] At step S904, afirst movable reflection mirror reflects the aligned light rays to form reflected light rays. In embodiments, the process continues with step S906.

[0122] At step S906, amovable focusing lens propagates the reflected aligned light rays to form an intermediate image based on the reflected aligned light rays. In embodiments, the process continues with step S908.

[0123] At step S908, a second movable reflection mirror reflects the intermediate image to form a reflected intermediate image. In embodiments, the process continues with step S910.

[0124] At step S910, a movable projection lens projects a final image based on the reflected intermediate image onto curable resin in a vat located on a projection plane. In embodiments, the projection pixel resolution of the final image is between 10 micrometers and 100 micrometers. In embodiments, the projection pixel resolution of the final image is adjustable by moving the movable projection lens. In embodiments, the process continues with step S912.

[0125] At step S912, a curable resin is developed (or cured) after exposure to the final image. In embodiments, curing the resin forms part, or all, of a 3D obj ect having a given feature size. In embodiments, the feature size is 20 micrometers. In embodiments, the feature size is no greater than 20 micrometers. In embodiments, the feature size is 50 micrometers. In embodiments, the feature size is between 20 and 50 micrometers. In embodiments, the feature size is larger than 50 micrometers.

[0126] In embodiments, for example when another part of a 3D object needs to be printed, the process may continue with step S914.

[0127] At step S914. set-up for a second initial image to be projected onto the resin in the vat is performed. For example, in embodiments, the scanning optics are adjusted such that the projection plane (the focus of the focusing lens) is moved. For example, in embodiments, motion stages may be actuated to move the first movable reflection mirror, movable focusing lens, second movable reflection mirror, and movable projection lens from first respective positions to second respective positions. In embodiments, the first respective positions may be determined based on a first coordinate location (which may be a point in the vat, or in the area beneath the vat) associated with the initial image. In embodiments, the second respective positions may be determined based on a second coordinate location (which may be a point in the vat. or in the area beneath the vat) associated with a second initial image. In embodiments, as depicted in FIG. 4A, the first coordinate location is a different coordinate location than the second coordinate location for example, when the first coordinate location is in the same layer as the second coordinate location (such as points 1 and 4). In embodiments, the printing194925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) platform may alternatively or additionally be adjusted to move the cured image vertically and allow for additional resin to be cured beneath it. In such embodiments, as depicted in FIG. 4A, the first coordinate location may be the same coordinate location as the second coordinate location, such as when the first coordinate location is in a different layer than the second coordinate location.

[0128] In embodiments, for example, when the 3D object is fully printed, the 3D object may be removed from the 3D printer (for example, by removing it from a printing platform of the 3D printer).Examples Demonstrating Embodiments of the Large Area, High Resolution Projection Stereolithography Disclosed Herein

[0129] The following illustrates nonlimiting examples of techniques, methods, systems and products in accordance with, and employing, embodiments of the present invention.

[0130] In the examples, PSL was adopted, an advantage of which is its ability to fabricate large parts with less resin

[0020] , The designed large-scale high-resolution SPSL printer, as illustrated in FIG. 1 A, includes a projection system located beneath a resin tank, projecting images below to solidify resin in the vat.

[0131] In the examples, printing resins were prepared by mixing an ultraviolet (UV) curable matrix (Rigid 10k, Formlabs, Inc.; Anycubic Tough resin) with appropriate amounts of milled short carbon fibers (7 pm in diameter, ~70 pm mean length, E&L Enterprises, Inc.) and silica nanoparticles (TS 720, Cabot, Inc.). Each batch began with 100 g of the matrix resin. 2 g milled carbon fibers were then added, followed by an hour of mixing on a roller (Fisher Development, Inc.). Next. 2 g of silica nanoparticles were added and manually mixed in a container. Finally, the resin mixture was thoroughly mixed on the roller for 24 hours. An advantage of this technique and composition is that the addition of carbon fibers stiffens the material, while the silica nanoparticles act as a rheology' modifier, minimizing aggregation and sedimentation. This stability makes the ink ideal for extended 3D printing sessions.

[0132] In the examples, the resin tank’s bottom was made of a transparent, non-stick Teflon film (FEP), which is affixed to a UV -grade fused silica window to provide a rigid structure. The build platform with a size of 22 cmx35 cm was mounted on an aluminum extrusion connected to translation stages (FIG. 1C). To mitigate the separation forces encountered during the printing of large-area patterns, two motion stages capable of sustaining a maximum load of 150 N were installed at each end of the aluminum extrusion, improving the load capacity and balance of the entire mechanical system.204925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0133] In the examples, a projection system capable of translating the projection images across the horizontal plane was used, consisting of consists of a light engine, three lenses, two reflection mirrors, and two motorized linear translation stages, as shown in FIG. 1 C. The fundamental working principle of the system is based on the infinity -corrected optical design

[0021] , as shown in FIG. 1C. Here, light rays emitted from the light engine, which is equipped with a DMD (digital micro-mirror device) chip, pass through a collimating lens and enter as an infinity parallel beam in the focusing lens, forming an intermediate image. The intermediate image is subsequently relayed through a projection lens and formed into the final image. In contrast to a conventional projection system in PSL printing technology, where the focused image will be out of focus as soon as the lens moves, the infinity -corrected projection system disclosed herein allows the translation of the projection image over a large distance while keeping the focus and intensity — the image size stays relatively constant even if the distance between the collimating lens and the focusing lens is changed. Thus, the projection images can be translated across a high-speed motion axis without moving light engine.

[0134] In theory, collimated light should maintain a consistent diameter from the lens to infinity. However, in practice, no physically collimated beam can maintain an exact diameter as it travels. The divergence of the beam, which is the rate at which its diameter changes, is influenced by the characteristics of both the light source and the collimator

[0046] , To minimize divergence, the distance of the setup was held to be within 50 cm in the examples. To assess the performance of the system, Zemax simulation software with a wavelength of 405 nm was used to simulate the performance of the final design. Two standard analysis tools were employed. The first analysis tool used was “Field Curvature and Distortion” to assess astigmatism and distortion of the optical system. A maximum astigmatism of 20 pm and a maximum distortion of less than 0.002% at the edge of the image plane was observed. Another analysis tool used to evaluate the system's performance is the spot diagram, which plots the intercepts of rays on the image plane. The root mean square (RMS) of the radial size is a parameter used to evaluate the spot size on the spot diagram, and it gives a rough estimate of the spread extent of light. The spot sizes of the given plots were found to be less than 20 pm, indicating good performance.

[0135] As shown in Fig. ID, the light engine was fixed on the ground in the examples, while the scanning optics move along the x-y directions, sequentially projecting images onto the resin vat. Advantages of this design includes reducing the weight of the moving parts, enabling faster, more efficient movement while minimizing vibration and enhancing precision.214925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0136] As depicted in FIG. 2A, the optical system (e.g., scanning projection system 201) used in the examples includes an illumination source (the DMD chip 103). collimating and focusing lenses 104 and 110, projection lenses 1 12, and two reflection mirrors 108a and 108b. In this example, a light engine from Wintech, Inc., equipped with a DMD chip of 1140x912 pixels, was utilized. The incident angle of light emitted from the DMD is approximately 11°. To optimize optical coupling efficiency, a collimating lens was selected whose relative aperture ( NA = -, where D is the diameter, and fcis the focal length of the lens) that closely approximated two times the tangent value of the incident angle (0.389). The optical system further includes beam splitter 202 strategically positioned behind the collimating lens, directing part of the beam to a CCD camera 204 to capture the final projection image. A tube lens serves as the focusing lens to create an intermediate image, the size of which is determined by the magnification ratio (ff / fc) and the size of the DMD chip. To preserve the integrity of the final projected image, the entrance pupil of the projection lens employed is designed to be larger than this intermediate image.

[0137] FIG. 2B provides a proj ection image captured by a CCD camera in accordance with embodiments of the present invention. Fig. 2B illustrates the CCD image 210 captured postfocus calibration, demonstrating that the projected pattern retains its integrity with minimal distortion or loss of sharpness, even at the pixel level on the edges of the projection area. However, the projected image exhibits non-uniform light intensity across the printing area, with a brighter center 212, and a dimmer edge 214. 3D printed lattice 216 is the 3D printed structure of the captured CCD image after being corrected.

[0138] FIG. 2C illustrates a gray mask process used to mitigate non-uniform light intensity in accordance with embodiments of the present invention. In the examples, the light intensity distribution across various points of the projection area was measured using a UV sensor (e.g., CCD camera 204) to create a measured light intensity profile 220. Subsequently, a gray mask 224 w as created by fitting these measurements to a smooth curve 222. This gray mask was then superimposed onto the original projection image (creating masked projection image 226) to correct for the light intensity variations, effectively standardizing the illumination across the entire printing area.

[0139] FIG. 2D is a set of photographs depicting a pyramid microstructure array fabricated in accordance with embodiments of the present invention. To demonstrate the resolution capabilities of the projection system, the projection area was configured to measure 20x 16 mm2and a tiny pyramidal array 250 was fabricated using the developed carbon fiber reinforced224925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) polymer (CFRP) composite, as illustrated in FIG. 2D. As shown by Pyramid 250a and Pyramid 250b, the printed part displays sharp edges with features 252 as small as less than 50 pm. (and 100 pm in height), underscoring the superior performance of the optical system disclosed herein.

[0140] FIG. 8B illustrates an example of a processing and control schematic of the printing system, comprising a processing system 820. a control system 830. and mechanical system 840. In embodiments, the process used begins with a 3D model 822, which is sliced into 2D images using a software 824 (e.g., Netfabb, nTopology, g., SLIC3R, CURA, OCTOPRINT, KISSSLICER, PRUSASLICER, SELFCAD, ICESL, MANGO3D, LYCHEE, TINKERINE, to name a few) (which are examples of processing system modules 802). In embodiments, these images may then be processed using MATLAB 826 or other software (which is an example of a processing system module 826) to segment them into sub-images (e.g., sliced images 828). An optimization code 830, discussed above, for scanning paths is utilized to identify void subimages within each layer, optimize the scanning paths, and generate a file with the coordinates of the individual images.

[0141] In embodiments, the file with the coordinates of the individual image includes code such as G-code and / or other machine-readable instructions. In embodiments, the resulting scanning file is executed using LabVIEW 842 or other suitable software.

[0142] In embodiments, the file contains machine-readable instructions which, when executed by a three-dimensional printer (e.g., by a controller operably connected to components of the three-dimensional printer such as the light source and elevator, as discussed below), cause the light source to project patterns of light in accordance with exemplary embodiments of the present invention.

[0143] The control system (control system 840) used includes two microcontrollers (corresponding to controller(s) 808), including a Duet 2 board 844 and an Arduino board 846, both connected to a PC and managed by the LabVIEW program 842. The Arduino board 846 is operably connected to and regulates a shutter servo 862 (e.g., corresponding to shutter servo 814) that controllers a shutter which blocks background stray light in the absence of exposure, while the Duet 2 board 844, connected to power supply 252, is operably connected to and manages the motion stages 864 of the optical system (not shown), as well as elevator 866 of the printing platform (not shown), and receives signals from limit switches 848. The LabVIEW program 842 is also responsible for controlling the projector 850 to project UV patterns.234925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011)

[0144] The mechanical system (mechanical system 860) used in the examples includes motion stages 864 along the x and y axes to control the location of the movable portion of the scanning optics, an elevator 866 to control the z-axis for the printing platform, and a shutter servo 862.

[0145] FIG. 3A is a diagram showing a design of a vase which was divided into layers, images, and subsections of images in accordance with exemplary embodiments of the present invention. In the examples, to demonstrate the large-scale, high-resolution printing capabilities of embodiments of the present disclosure, vase 300 with a volume of 20x20x50 cm3was designed, featuring a minimal strut thickness of 50 pm. The 3D model was sliced into 2D images with predefined pixels (slices 302a, 302b, 302c. 302d, and 302e), segmented into sets of sub-images (e.g., with sub-image sections 304c for slice 302c, include images 306, 308, and 310) for sequential projection onto the vat as the stages moved in x-y directions, as shown in Fig. 3A. Each sub-image covers a specific area, initiating resin polymerization to form solid layers. The images for the vase were divided into 35 sections (5 m sub-sections x 7 n subsections).

[0146] FIG. 3B provides a schematic drawing illustrating the light intensity between neighboring sections of an image in accordance with exemplary7embodiments of the present invention. FIG. 3C provides curing depth measurements of the vase depicted in FIG. 3A in accordance with embodiments of the present invention.

[0147] In the examples, to enhance the bond between sections and prevent overcuring from double exposure in overlap areas, a gradient grayscale technique was used in accordance with embodiments of the present invention. This technique adjusts the projection energy7in overlapping sections, smoothing transitions and maintaining dimensional accuracy, as shown in FIG. 3B, with image 306 and image 308 sharing a corresponding overlap 312, and image 308 and image 312 sharing a corresponding overlap 304. The intensity7of image 306 and image 308 was lowered in overlap 312, and the intensity of image 308 and image 310 was lowered in overlap 314.

[0148] In the examples, Autodesk Inventor and nTopology, were used to design the Voronoi vase 300 (see FIG. 3 A, 5C) in accordance with embodiments of the present invention. Initially, a solid 3D model of the vase was created in Inventor and imported into nTopology . A randomized list of points with gradient spacing was generated within the vase, narrowing from 10 mm at the ends to 1 mm at the neck (see FIG. 5C). The Voronoi lattice is formed by connecting these points and thickening each beam variably to adjust for the narrower neck244925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) section. Beam thickness ranges from a minimum of 50 pm to a maximum of 2 mm. nTopology was used to directly slice the 'implicit body' into images (e g., 302a, 302b. 302c, 302d, 302e, to give a few examples), with each layer set to a thickness of 50 pm and an image resolution of 5700x6384 pixels to meet the specifications. These images were then segmented in MATLAB into 5x7 sub-images (e.g., sub image subsections 304c, to give an example), each with 1140x912 pixels, ready for transmission to the light engine.

[0149] To enhance printing efficiency for complex structures, the examples used a more efficient method than shifted the traditional S-shape scan path, as disclosed herein. While it is possible to find the shortest scan time path by an exhaustive method, it becomes extremely challenging when k=20 (where k refers to the number of sub-images with patterns in one layer), like the vase in FIG. 3A. The presently disclosed method involves minimizing scanning time moving over “void areas’; addressing a common problem similar to the "Traveling Salesman Problem" (TSP). For practical resolution, a MATLAB code utilizing a genetic algorithm

[0022] to optimize the scan path for each layer, identifying necessary projection areas and reducing unnecessary movements.

[0150] The printing time formula, T = N * (Tr+ kTe+ (k — l)Tm) , quantifies the overall printing time where N is the number of layers, Tris the recoating time, Teis the exposure time, and Tmis the stage moving time. The examples speed up stage movement to reduce printing times. Tm, is calculated using the formula: Tm= “ + “■ where d is the moving distance. V is the maximum moving speed, and a is the acceleration speed.

[0151] FIG. 4A provides an illustration of an optimized scan path in accordance with exemplary7embodiments of the present invention. Path 400 (shown in dashed) represents the conventional ‘S’ path, whereas path 402 (between coordinates 1, 4. 3, 5, 6 and 2) on layers «, n +1, n +2, .... (shown in solid line) represents the shortest scan time path among all possible routes that pass through the necessary projection areas. It is assumed two motion stages move simultaneously when moving from one location to another, and the slower stage is used to quantify the time cost. In embodiments, the optimized path may differ depending on the speed of the linear stages. It is worth noting that, unlike conventional TSP where the optimized path needs to be connected at both the beginning and end, the scanning method disclosed herein has a fixed starting point and an open endpoint. For layer n, the scanning begins at the point 1 and ends at the point 6. Then, the endpoint of layer n becomes the starting point for layer n+1, and so on. This approach further reduces unnecessary scan movements during layer changes.254925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011)

[0152] As demonstrated in FIG. 4A. this approach uses a fixed starting point and an open endpoint for each layer, considerably improving scanning efficiency by adapting the scan path dynamically. In particular, this method increased the scanning speed by a factor of 1.75 for a layer with 20 sub-images and tripled the printing speed for simpler layers with 6 sub-images, as shown in Fig. 3B.

[0153] FIG. 4B is a chart comparing conventional scanning methods with a scanning method performed in accordance with exemplary embodiments of the present inventions. FIG. 4B compares the time cost of the TSP scanning method in accordance with embodiments of the present dislcosure with the conventional S-shaped scanning method. FIG. 4B shows scanning times 410, 412, and 414 associated with the S-shaped scanning method, the optimized scanning method on a layer with 20 sub-images, and the optimized scanning method on a layer with 6 sub-images, respectively. Specifically, when k=20 (where k is the number of sub-images of a layer), the scanning speed can be improved by a factor of 1.75. For the case in FIG. 4A (fc=6), the printing speed is 3 times faster than the S-shaped method.

[0154] FIG. 4C is a chart showing the motion profile of the scanning stage in accordance with exemplary' embodiments of the present invention.

[0155] FIG. 4D is a chart showing the estimated printing time with vary ing maximum speed and acceleration in accordance with exemplary embodiments of the present invention. Curve 430 represents an acceleration of 500 mm / s2, curve 432 represents an acceleration of 750 mm / s2, and curre 434 represents an acceleration of 1000 mm / s2. The formula used to calculate the printing time was the printing time formula, T — N * (Tr+ kTe+ (k — l)Tm), as previously described. For purposes of the estimation, it was assumed that d = 40mm, Tr= 4s, Te= Is, fc=15. As FIG. 4D illustrates, increasing acceleration speed beyond 500 mm / s2does not significantly decrease printing times. However, by increasing the maximum moving speed from 25mm / s to 75mm / s. the examples illustrate a 33% reduction in printing time for a configuration with 15 sub-images.

[0156] FIG. 4E is a 3D map illustrating showing the estimated printing time with varying maximum speed and acceleration in accordance with exemplary embodiments of the present invention. Curved plane 440 illustrates the estimated print time w ith 5 sub images, curved plane 442 illustrates the estimated print time with 10 sub images, and curved plane 444 illustrates the estimated print time with 15 sub images. Estimated printing time with varying maximum speed, acceleration, projection area counts, demonstrating that higher speeds can decrease printing times by up to 33% for k=15 (as shown by curved plane 444).264925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0157] FIGs. 5A-5C are photographs of large-scale carbon fibre-reinforced polymer (CFRP) objects printed in accordance with embodiments of the present disclosure. With the developed printer, CFRP lattices ranging in size from 10 to 50 cm were successfully printed, as shown in FIGs. 5A-5C.

[0158] FIG. 5 A is a photograph of large-scale hierarchical CFRP truss-lattice materials fabricated in accordance with exemplary embodiments of the present invention. The CFRP has a truss-lattice with a strut radius equal to 150 pm. FIG. 5 A features a group of hierarchical CFRP lattice materials composed of octet trusses, with an overall size of 18 cm and strut radii as thin as 150 pm. These materials exhibit nearly isotropic properties and high structural connectivity in stretch-dominated architectures.

[0159] FIG. 5B is a photograph of CFRP plate-lattice materials fabricated in accordance with exemplar^' embodiments of the present invention. FIG. 5B demonstrates the 3D printing of plate-lattice materials using CFRP, which feature a more efficient architecture with higher energy absorption capability compared to truss-lattices.

[0160] FIG. 5C is a photograph of large-size high-resolution CFRP Voronoi vase fabricated in accordance 'ith exemplary embodiments of the present invention. The vase is designed to have gradient unit cell size and strut thickness along its vertical direction. FIG. 5C presents the fabricated Voronoi vase 500. The vase measures ~50 cm in length. As demonstrated, it has a gradient unit cell size ranging from 10mm to 1mm (included the cell sizes of 10 mm, 8 mm, and 5mm, as demonstrated by sub-sections 514, 512 and 510). Additionally, the strut size has a minimal strut thickness of 50 pm (see strut 520), but can be larger, depending on the called for feature size (see strut 522, which a strut thickness of 2 mm). This showcases the ability to produce large-scale high-resolution objects in accordance with embodiments of the present invention.

[0161] Printing large-scale structures using a bottom-up system poses significant challenges in controlling the separation force between the newly cured layer and the separation film. This process, similar to a vacuum, can cause the resin to fill the gap. The separation force is influenced by factors such as contact area, resin viscosity, exposure energy, and separation speed [23-27], In the examples, the separation speed during the initial peeling process w as set to a low' value of 0.2 mm / s to ensure proper detachment.

[0162] Traditionally, reducing the mass of structural systems and enhancing the energy dissipation of materials have been the subjects of the automotive industry over the years

[0028] , CFRP is known for its high stiffness-to-weight ratio and hence can be useful in extensive274925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) research and industrial uses. Incorporating CFRP in AM provides further opportunities for significant weight reduction

[0029] , Benefiting from the advantages of AM for free-forming, it is possible to manufacture components with complex internal structures to meet specific energy absorption requirements

[0030] ,

[0163] To further demonstrate the capability of the developed system, a lightweight car bumper energy absorber was designed and manufactured in the examples, as illustrated in FIGs. 6A-6E. The CFRP composite utilized in the examples was tested to be isotropic, with a Poisson’s ratio of .3.

[0164] FIG. 6 A illustrates a photograph of a maize stem under a microscope, as well as a lattice replicating the tissue structure of the maize stem. The design of the energy absorber was inspired by the intricate structure of cortical tissues of maize stems (see photograph 600), where the thickness and size of cells vary at different locations of the tissues, resulting in efficient energy absorption (Fig. 6A).

[0165] FIG. 6B illustrates a schematic of a conventional car bar energy’ absorber 604 attached to car 606. The examples incorporated hexagonal honeycomb structures 602 as the inner filler, while retaining the outer shell to effectively distribute the load (outer shell dimension provided by Ford Inc.). To further enhance its performance, the examples introduced two topological gradients to the honeycomb structure: thickness gradient and unit cell size gradient. The effect of these two gradients was studied in numerical simulation in Abaqus.

[0166] FIG. 6C is stress-strain chart for three different lattice designs. The stress-strain chart shows the stress-strain curves of three representative honeycomb lattice configurations, where the curve 622 corresponds to the baseline design 602 with uniform thickness and cell size, the curve 620 corresponds to the baseline design with a graded thickness of 10%, and the curve 624 corresponds to a lattice with graded cell size.

[0167] The examples investigated two critical parameters: peak stress (strength o_p) and strain energy density (SED) 626. which was calculated as the enclosed area of the stress-strain curve and had a unit of MJ / m3. Notably, under compression, the uniform lattice exhibited global buckling, with two layers buckling simultaneously. After the first peak, a prolonged plateau was observed, followed by a drop, signifying the collapse of one layer.

[0168] Introducing thickness gradients with an offset of 10% (varying from 90% to 110%) results in stress-strain curve 620. As shown by stress-strain curve 620, the peak stress of the graded lattice was lowered by 17%, from 1.98 MPa to 1.65 MPa, compared to that of the uniform lattice. Moreover, a higher second peak stress in the stress-strain curve w as observed,284925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) which resulted in an increase in the volumetric energy absorption at approximately 15% strain. This was because the top layer had lower strength, which buckled first before the buckling of the second layer with a thicker wall. This sequential buckling mechanism differed from the uniform lattice buckling and contributed to enhanced energy absorption.

[0169] Curve 624 illustrates the stress-strain curve of the lattice with graded cell size, which exhibited an even higher strain energy density’. This improvement is attributed to the local buckling of the small unit cell members of the lattice. Specifically, the small cells gradually buckle and collapse until the larger cells fail. This local buckling provides a more steady stress level after the peak stress, resulting in a higher average plateau stress level and thus providing additional energy absorption capacity.

[0170] Even though the designs corresponding to the curves in Fig. 6C have different geometries, they all have the same relative density. Therefore, a fair comparison can be made between them based on the plotted stress-strain curves. Higher energy’ absorption is usually desirable, and lower peak stress is preferred as the stress will ultimately be transferred to the vehicle body or the object that was impacted.

[0171] FIG. 6D is a figure of merit chart for three different lattice designs corresponding to the curves shown in FIG. 6C. To further evaluate the performance of each design, a figure of merit was defined to account for both SED and peak stress using the equation: FOM=SED- w_i °_P- where o_p is the strength of the structure, w_i is a weight factor, which was set to 10%. This equation was utilized this equation to identify the optimal design for the specific application scenario. A higher FOM value indicates better performance for a given design.

[0172] FIG. 6D shows the evaluation of multiple designs with different configurations depending on the gradient value and plotted their corresponding figure of merit (FOM) values. FIG. 6D illustrates that introducing either a thickness gradient of 10% or varying cell sizes can improve the FOM. Varying the cell size gradient produced optimal design 632, and varying the thickness gradient produced optimal design 630. Based on these results, we identified the optimal design that maximized the FOM and generated the final design by superimposing these two gradients into a single design volume.

[0173] FIG. 6E is a design of a lightweight bumper energy' absorber 650 featuring gradient wall thickness and unit cell sizes, capable of being printed in accordance with exemplary embodiments of the present invention. As depicted in FIG. 6E, the middle section of the absorber to serve as the impact area 640, which was filled with graded unit cell sizes (632) to enhance its energy’ absorption capabilities. In addition, a thickness gradient of 10% 630 was294925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) applied along the width direction to induce sequential buckling in the remaining areas of the absorber. The absorber design 650 spans roughly 110 cm in length and stands 13.3 cm wide and 10.2 cm tall, with the thinnest plate measuring only about 1 mm thick.

[0174] FIG. 7A is an image of a sliced layer of the energy’ absorber 650 shown in FIG. 6E segmented into sub-images in accordance with exemplary' embodiments of the present invention. To accommodate the size of the vat, the entire absorber was divided into four parts, with two parts configured to be printed simultaneously, as illustrated in FIG. 7A. Each sliced layer (e.g., layer 790, depicted in FIG. 7A) consisted of 3x5 sub-images. The total printing size was 22.428 cm2.

[0175] FIG. 7B is a photograph showing two parts of the energy absorber design 650 shown in FIG. 6E which was printed in accordance with exemplary' embodiments of the present invention. As shown in FIG. 7B, two parts, 740a and 740b, of the energy' absorber design 650 are attached to the printing platform 722 (similar to printing platform 122) of 3D printing system 700 (similar to 3D printing system 100). As discussed herein, and in accordance with embodiments of the present invention, the 3D printing system 700 also includes a vat 720 (which may be similar to vat 120) and a scanning projection system 701 (similar to scanning projection system 101) beneath the vat. The printing resin was formulated with 2 wt% short carbon fibers.

[0176] As FIG. 7B show s, two parts of the energy absorber, 740a and 740b were printed simultaneously' in one batch, using CFRP resin. The small honeycomb lattices in the zoomedin photo demonstrate a satisfactory' alignment between tw o bridging sub-sections 742.

[0177] In the examples, after the printing, the support structure was removed, and the absorber was post-cured. The four parts were then assembled using J-B Weld ClearWeld glue, as shown in FIG. 7C.

[0178] FIG. 7C is a photograph of a large-scale car bumper energy absorber 740 corresponding to the design shown in FIG. 6E as fabricated in accordance with exemplary embodiments of the present invention. The large-scale car bumper energy absorber 740 was fabricated with a length of 110 cm, width of 13.3 cm wide, and height of 10.2 cm. The car bumper energy' absorber 740 exhibited excellent stiffness and toughness during mechanical testing. The absorber 740 has a relative density of only -40% and has optimized energy absorption capability. The bumper energy absorber 740 designed and printed has an exceptional property of efficiently absorbing significant amounts of energy while maintaining a relatively' lightweight structure. This property is particularly7advantageous in the automotive304925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) industry, where utilizing lightweight materials can enhance fuel efficiency and minimize emissions.Multi -Material DLP Printing

[0179] Embodiments of the invention also include a novel multi-material VPP system and method that utilizes centrifugal-assisted and ultrasonic-assisted washing in an immiscible, lighter liquid to remove resin residue. In embodiments, unlike, solvent-based methods, these techniques do not dissolve the residue but instead dislodges it through mechanical agitation while simultaneously replacing it with the immiscible liquid. The macro-scale centrifugal force effectively removes larger residues, while ultrasound assists in dislodging finer residues, including particle-loaded resins such as piezo-ceramic-filled formulations. Since water (or other liquids) is immiscible with many photocurable resins and lighter in density’, the displaced residue sinks to the bottom of the washing chamber, preventing reattachment and contamination. Thus, an advantage of the present invention is that it preserves interfacial strength, prevents cracking, and ensures clean and well-defined material boundaries of 3D printed objects.

[0180] A still further advantage is that this method enhances charge-programmed selective deposition after printing, seamlessly integrating conductive and non-conductive regions within a single print. Accordingly, the system can be used for the micro-resolution fabrication of 3D electronic devices, such as 3D interconnects and piezoelectric force decoupling sensors (as shown below), enabling the seamless integration of functional electronic materials into complex geometries while maintaining structural integrity and material selectivity.

[0181] FIG. 10 is a schematic of a multi-material digital light processing system incorporating a centrifugal-assisted and ultrasonic-assisted washer in accordance with exemplary embodiments of the present invention. FIG. 10A is a schematic of a centrifugal- assisted and ultrasonic-assisted washer in accordance with exemplary embodiments of the present invention.

[0182] As shown in FIG. 10, in embodiments, a multi-material DLP system (e.g., 3D printer 1000) includes a projection system (e.g., projection system 1001). a plurality of vats (e.g., vats 1020), a rotary build stage 1022, and an ultrasonic washer 1030. In embodiments, these components may be configured similarly to those discussed employed and with respect to 3D printing system 100 (FIGs. 1A, 1C) and scanning projection system 101 (FIGs. IB, ID) and scanning projection system 201 (FIG. 2A)314925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0183] In embodiments, the projection system includes a light engine (e.g., UV projector 1002) and other optics (e.g.. optics 1024). In embodiments, the optics include one or more of a collimating lens, a reflection mirror, a focusing lens, a reflection mirror, a projection lens, as discussed further with respect to FIG. IB and FIG. 2A. For example, the optics may include a mirror for reflecting light from the ultraviolet projector towards one or more of the plurality of vats. In embodiments, the optics may include a CCD camera (e.g., CCD Camera 204), as discussed with respect to FIG. 2A. In embodiments, one or more components of the projection system are attached to one or more motion stages (e.g., x motion stage 1028, also referred to as “Switch Direction (x)'’ to give an example) configured to move the respective one or more component (e.g., a mirror, a projector, a lens, to give a few examples) along a two-dimensional plane. In embodiments, by moving one or more components of the projection system, the vat in which three-dimensional printing is occurring can be selected and adjusted. The projection system may be a scanning projection in accordance with exemplary embodiments of the present inventions.

[0184] In embodiments, the plurality of vats includes a first vat (e.g., vat 1020a) and a second vat (e g., vat 1020b). In embodiments, the plurality of vats includes additional vats (not show n). In embodiments, the plurality of vats may be attached to and / or rest on a vat platform 1032. The vat platform may include openings, either hollow or covered using material configured to allow light to pass through (e.g., glass), such that the vat platform can support the plurality of vats while also allowing for the projector to project light into one or more vats. In embodiments, the plurality of vats and / or the vat platform may be attached to one or more motion stages and / or an elevator. In embodiments, the one or motion stages and / or the elevator may be configured to allow the vat platform to move in the x. y , and / or z directions, respectively (e.g.. along a two-dimensional plane in the x-y direction using motion stages and in the z direction using an elevator, to give an example). In embodiments, the one or motion stages may be configured to allow7the vat platform to move rotationally. For example, as an alternative to, or in addition to, moving the UV projector 1002, the vat platform may rotate to enable printing using resin in the second vat 1020b upon exposure to UV light from the UV projector after having first printed in the first vat 1020a. In embodiments, the plurality of vats and / or the vat platform are stationary, while other components move around them. In embodiments, both the plurality of vats and / or the vat platform and other components of the three-dimensional printing system are configured to move324925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011)

[0185] In embodiments, the projection system is configured and used to project a projected image (not shown) on a projection plane (not shown) of a first vat of the plurality of vats (e.g., vat 1020a), so as to form layers of three-dimensional objects upon photopolymerization based upon the images / patterns displayed on the resin. In embodiments, the projection system is configured and used to project a projected image (not shown) on a projection plane (not shown) of a second or third vat of the plurality of vats (e g., vat 1020b, to give an example), so as to form additional layers of three-dimensional objects upon photopolymerization based upon the images / patterns displayed on the resin. For example, the projection system may be used to cure resin exposed to a first image to form a first layer of a three-dimensional object, and then to cure resin exposed to a second image to form a second layer of the three-dimensional object. Continuing the example, the second layer may be cured in a different vat, using a different resin.

[0186] As shown in FIG. 10A, in embodiments, the ultrasonic washer (e.g., ultrasonic washer 1030) comprises a washing chamber (e.g., washing chamber 1034) and an ultrasound generator (e.g.. ultrasound generator 1036). In embodiments, the washing chamber is a hollow cylinder enclosed with a cylindrical wall and a floor and is configured to hold a wash medium. In embodiments, the wash medium is selected to be an immiscible, lighter liquid (e.g., liquid 1038) than resins in the plurality of vats (e.g., resin 1018a in vat 1020a and resin 1018b in resin 1020b, to name a few examples). For example, the wash medium may include water and / or hexane, to name a few. In embodiments, the w ash medium includes one or more of an aqueous and a non-aqueous liquid. In embodiments, the wash medium includes one or more additives such as buffers, salts, pH modifiers, stabilizers, and / or dispersants. In embodiments, the washing chamber may also include resin waste (e.g.. waste 1040) displaced during the washing process. In embodiments, the ultrasound generator is configured to propagate ultrasonic waves through the wash medium and any waste to dislodge residue from a three-dimensional object placed within the washing chamber. In embodiments, since water is immiscible with many photocurable resins and lighter in density, the displaced residue sinks to the bottom of the washing chamber, preventing reattachment and contamination.

[0187] In embodiments, the frequency of the ultrasonic waves is selected based on the size of the three-dimensional object being printed. In embodiments, the ultrasonic waves may be selected to be at 40khz. In embodiments, the ultrasonic w aves may be selected to be from 20khz - 200khz.334925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0188] In embodiments, the multi-material DLP system includes a plurality of washing chambers (e.g.. washing chamber 1034 as well as additional washing chambers not shown). In embodiments, each of the plurality of washing chambers is associated with a respective one or more vats (e.g., a first washing chamber for a first vat, a second washing chamber for a second vat. etc). In embodiments, the plurality of washing chambers may include a plurality of liquid types. In embodiments, the plurality of washing chambers may be used sequentially. In embodiments, the plurality of washing chambers may be used to clean specific resins.

[0189] In embodiments, the rotary7build stage provides a platform for the layers of resin to attach to as it is cured. In embodiments, the rotary build stage is operably connected to one or more elevators used to raise and lower the build stage. For example, in embodiments, after a layer is printed, the elevator raises the rotary build stage slightly, enabling the printing of another layer using the same resin. As another example, in embodiments, the elevator raises build stage so as to lift out the printed portion of a three-dimensional object from a vat of resin, enabling it to be placed in the ultrasonic washer, in another vat of resin, or removed. In embodiments, the rotary build stage is operably connected to, or otherwise moveable by, one or motion stages, enabling the build stage to be moved between the plurality of vats and the ultrasonic washer.

[0190] In embodiments, the rotary7build stage rotates in order to produce a macro-scale centrifugal force to effectively remove larger residues while retaining the printed portion of a three-dimensional object on the printed layer. In embodiments, since water is immiscible with many photocurable resins and lighter in density, the displaced residue sinks to the bottom of the washing chamber, preventing reattachment and contamination. In embodiments, the rotational build stage rotates at a speed of hundreds of RPMs (e.g., between 100 and 1000 RPMs, to give an example). In embodiments, the rotational build stage is configured to rotate in various directions. For example, the rotational build stage may rotate in opposite directions in subsequent periods of time so as to “shake off” excess residue.

[0191] In embodiments, a three-dimensional object completes a full rotation within the wash medium. In embodiments, the three-dimensional object completes less than a full rotation within the wash medium. In embodiments, the three-dimensional object completes two or more rotations within the wash medium.

[0192] In embodiments, the wash medium may accumulate in one or more of the plurality of vats (e.g., vats 1020a and 1020b) as shown in FIG. 10A, a result of the cleaning process. In embodiments, this produces little if any interference with the cleaning process since the wash344925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) medium is lighter than resin. In embodiments, upon resin / material change, any water is removed from the plurality of vats and any waste is removed from the washing chamber.

[0193] In embodiments, the multi -material DLP system is operably connected to and / or includes PC(s) 800, a power supply 810, limit switches 812, controller(s) 808, motions stages 128a, 128b, shutter servo 814, light engine / projector 102, CCD camera 204, one or more components of the processing system 820. one or more components of the control system 840, and / or one or more components of the mechanical system 860, as discussed further with respect to FIGs. 8A and 8B.

[0194] FIGs. 11A-11C are photographs of aspects of a multi-material digital light processing system incorporating a centrifugal-assisted and ultrasonic-assisted washer in accordance with exemplary embodiments of the present invention.

[0195] As depicted in FIG. 11A, rotary' print stage 1122, with a three-dimensional structure / object 1124 attached, is in vat 1120 with the three-dimensional structure 1124 partially submerged in a wash medium 1138 (e.g., water) and material 1118 (e.g., resin Ml). As shown in FIG. 11 A, the wash medium 1 138 sits atop material 1118. The wash medium is from a washing chamber (e.g., washing chamber 1134).

[0196] As depicted in FIG. 11B, between or after cleanings, three-dimensional structure 1124, still attached to the rotary’ print 1122, is placed in the washing chamber 1134. which includes a wash medium 1138 and waste residue 1140. The waste residue is printing material (e.g., material 1118, such as resin), cleaned off after printing in a vat (e.g., vat 1120).

[0197] As depicted in FIG. 11C, after a cleaning (e.g., after the rotary build stage has been moved to place the three-dimensional object in another vat), the washing chamber 1034 includes both the wash medium 1138 (e.g., water, to give an example) and the waste material 1140 (e.g., collected residue). In embodiments, the collected residue is removed by flushing the washing chamber and refilling it or otherwise emptying it.

[0198] FIG. 12 is a flow chart depicting a process for 3D printing a three-dimensional multi -material object in accordance with exemplary embodiments of the present invention.

[0199] In embodiments, the process begins with step SI 200. At step SI 200, resin is exposed to light (e.g., UV light projected from a projector) to cure a layer of a 3D object on a rotary’ build stage. In embodiments, the process may continue with step SI 200, for example, where another layer using the same resin in the same vat is to be printed. In this example, the rotary' build stage is raised as to enable the printing of another layer of the three-dimensional object. In embodiments, the process continues instead with steps S1202.354925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0200] In embodiments, at step S 1202, the three-dimensional object is removed from the vat while attached to the rotary- build stage. In embodiments, the rotary build stage is removed from the vat by raising it using an elevator operably connected to the rotary stage. In embodiments, the rotary build stage rotates after being removed from the vat so as to cause excess resin to drip from the three-dimensional object. In embodiments, the process continues with step SI 204. In embodiments, for example where the three-dimensional object is competed (or a phase of printing is completed), the process continues with step S 1212.

[0201] In embodiments, at step S1204, the three-dimensional object is placed within a washing chamber of an ultrasonic washer having a wash medium while still attached to the rotary- build stage. In embodiments, the washing chamber includes a wash medium (e g., water and / or hexane, to give a couple of examples)and is used to collect waste residue from the three- dimensional object. In embodiments, the ultrasonic washer is operably connected to, and / or includes an ultrasonic generator for generator ultrasonic waves. In embodiments, the process continues with steps S1206 and S1208.

[0202] In embodiments, at steps S1206 and S1208, the ultrasonic washer and rotating build stage are used to clean residue from the printing process from the three-dimensional object.

[0203] In embodiments, at step S1206, the rotary- build stage rotates the three-dimensional object within the wash medium to remove residue from the three-dimensional object. In embodiments, the rotary build stage rotates at a speed of hundreds of RPMS (e.g., between 100 and 1000 RPMS, to give an example range). In embodiments, the rotary build stage operates at different rotational speeds throughout the cleaning process. In embodiments, the rotational speed is selected based on the size of the three-dimensional object printed. In embodiments, the rotary build stage switches rotational direction during the cleaning process. In embodiments, the rotary build stage completes one or more full rotations during step S1206. In embodiments, step S1206 may occur before, simultaneously with, and / or after the step S1208.

[0204] In embodiments, at step S1208. the three-dimensional object is exposed to ultrasonic waves / vibrations within the wash medium so as to remove residue from the three- dimensional object. In embodiments, the ultrasonic waves are generated by an ultrasound generator. In embodiments, the ultrasonic waves have a frequency of 40kHz. In embodiments, the frequency of the ultrasonic waves is based upon the size of the three-dimensional object printed.364925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011)

[0205] An advantage of performing both steps S1208 and S 1210 is that the rotational forces are able to facilitate the removal of larger residue while the ultrasonic waves are able to facilitate the removal of smaller (e.g., ultrafine residue). In embodiments, such waste residue sinks to the bottom of the washing chamber, enabling the wash medium in the chamber to be able to continue to be used to effectively clean the three-dimensional object.

[0206] In embodiments, additionally cleaning processing can take place. For example, compressed air may be used to agitate residue attached to the three-dimensional object, either before it is placed within the ultrasonic washer or during it. As another example, heating can be applied through the washing medium to aid the cleaning process.

[0207] In embodiments, the process continues from steps S 1206 and S 1208 with step S I 210.

[0208] In embodiments, at step S1210, the three-dimensional object is removed from the washing chamber while attached to the rotary' build stage. In embodiments, the rotary build stage is removed from the washing chamber by raising it using an elevator operably connected to the rotary stage. In embodiments, the rotary build stage rotates after being removed from the vat so as to cause excess washing medium to drip from the three-dimensional object. In embodiments, the process continues with step S1200 or step S1212. In embodiments, where the three-dimensional object is still being printed, the process continues with step SI 200. In embodiments, where the printing (or a stage of printing is completed), the process continues with step S1212.

[0209] In embodiments, for example where the three-dimensional object is competed (or a phase of printing is completed), the process continues with step S1212, where post-print processing occurs.

[0210] This process may be used to facilitate the efficient printing of three-dimensional multi-material objects. For example, where the first vat includes a first resin, a first layer made of a first material is cured during the printing process (S 1200). Continuing the example, after cleaning (e.g., using steps S 1202-S 1210), the three-dimensional can be placed in a second vat including a second resin in order to enable a second layer of a second material to be printed (S1200). In embodiments, these layers may be on the same ‘z’ level. Continuing the example, in embodiments, the object may then be cleaned again (e.g., using steps S1202-S1210). After this cleaning, the three-dimensional object may then be placed back in the first vat to allow another layer of the first material to be fabricated, back in the second vat to allow another layer of the second material to be fabricated, and / or in another vat (e.g., a third, fourth, fifth vat, to374925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) give examples) to allow another layer of a third material (corresponding to a third resin) to be formed. It will be understood that the exact order of which vats are used and which resins / materials are used will, in embodiments, depend on the three-dimensional object being printed. In this manner, multi-material objects may be formed quickly without the need for frequent material changes.

[0211] FIGs. 13A-13D are photographs of three-dimensional objects fabricated in accordance with exemplary embodiments of the present invention. FIG. 13A is a photograph a 3D ring interconnect 1300 with copper 1302 fabricated in accordance with exemplary embodiments of the present invention. FIG. 13B is a photograph of a miniature 3D force decoupling sensor 1310 with copper and piezo composites 1312 fabricated in accordance with exemplary embodiments of the present invention. FIG. 13C is a photograph of a larger 3D force decoupling sensor 1320 with copper and piezo composites 1322 fabricated in accordance with exemplary embodiments of the present invention. FIG. 13D is a photograph of a 3D base interconnect circuit board 1330 coated with nickel 1332 fabricated in accordance with exemplary embodiments of the present invention.

[0212] Methods for three-dimensional printing three-dimensional structures and multimaterial objects have been disclosed herein. It will be understood that such methods, in embodiments, are executed using computers and softw are modules on such computers, control systems, and components of three-dimensional printers, as discussed herein. For example, in embodiments, a three-dimensional multi -material object may be designed using CAD software (e g., KICAD, EAGLE, ORCAD, PROTEUS, CIRCUITMAKER, AUTODESK Fusion 360, PROTEUS, CIRCUITMAKER, SOLIDWORKS, BLENDER, MAYA, SKETCHUP, AUTOCAD, TINKERC AD, to name a few examples) to create a CAD model. In embodiments, the CAD model is a digital representation of a multi -matenal object.

[0213] In embodiments, the CAD model, which may be stored as a design file is obtained by a computer system, such as PC(s) 800 comprising processing system modules 802 and control system modules 806. In embodiments, the CAD model is created and stored on the computing device (e.g., using databases 804).

[0214] A computer or computer system typically includes one or more processors for executing processing system modules as well as a variety7of computer-readable media. Computer-readable media can be any available media that can be accessed by the computer and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media can include computer storage384925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory' or other memory' technology7, CD-ROM, digital video disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any' other medium which can be used to store the desired information and which can be accessed by' the computer.

[0215] Communication media typically embodies computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism, and includes any information delivery media. The term "modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF. cellular, infrared and other wireless media. Combinations of the any of the above should also be included within the scope of computer-readable media.

[0216] In embodiments, the computer system may also include a display device (e.g., a monitor) and one or more input devices (e.g., mouse and keyboard, to give an example). The computer system may also have an output device, such as a usb port, that enable the computer system to be operably connected, and transmit information to, a three-dimensional printer. Additionally, or alternatively, the computer system may be configured to store, for example via external memory like a USB stick, information, which can then be removed and plugged into the three-dimensional printer.

[0217] In embodiments, the computer system is used to generate a print filed based upon the CAD design file. In embodiments, software, such as slicer software (e.g., SLIC3R, CURA, OCTOPRINT, KISSSLICER, PRUSASLICER. SELFCAD, ICESL, MANGO3D, LYCHEE, TINKERINE, to name a few), may be used to generate the print file. In embodiments, the slicer software is the same as the CAD software. In embodiments, the slicer software is stored on the same computer as the CAD software.

[0218] In embodiments, the print file includes code such as G-code and / or other machine- readable instructions. In embodiments, the print file includes not only instructions as to how to394925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) layers needed for a three-dimensional object, but further includes instructions as to when the object should be cleaned, moved between vats, and other parts of the print.

[0219] In embodiments, the print fde contains machine-readable instructions which, when executed by a three-dimensional printer (e.g., by a controller operably connected to components of the three-dimensional printer such as the UV projector, rotary building stage, an ultrasound generator to name a few), cause the three-dimensional printer to perform printing methods in accordance with exemplary embodiments of the present invention.

[0220] In embodiments, the claimed invention includes a non-transitory computer-readable medium storing instructions that, when executed by one or more processors of a system, cause the system to perform a method comprising: a) exposing a first resin in a first vat to light so as to cure a first layer of a three-dimensional object upon a rotary build stage; b) removing the three-dimensional object from the first vat while still attached to the rotary build stage; c) placing the three-dimensional object in a wash medium within a washing chamber while the three-dimensional object is still attached to the rotary build stage; d) rotating the three- dimensional object within the wash medium; e) exposing the three-dimensional object to ultrasonic waves within the wash medium generated by an ultrasonic generator; f) removing the three-dimensional object from the wash medium; g) exposing a second resin in a second vat to light so as to cure a second layer of the three-dimensional object upon the rotary build stage; h) removing the three-dimensional object from the second vat while still attached to the rotary' build stage; i) placing the three-dimensional object in the wash medium within the washing chamber while the three-dimensional object is still attached to the rotary build stage; j) rotating the three-dimensional object within the wash medium; k) exposing the three- dimensional object to ultrasonic waves within the wash medium generated by an ultrasonic generator; and 1) removrng the three-dimensional object from the wash medium.

[0221] In embodiments, the claimed invention includes a non-transitory computer-readable medium storing instructions that, when executed by one or more processors of a system, cause the system to perform a method comprising: a) emitting, by an illumination device, light rays corresponding to an initial rmage; b) propagating the light rays emitted from the rllumination device through the collimating lens to form aligned light rays; c) reflecting, by a first movable reflection mirror, the aligned light rays to form reflected aligned light rays; d) propagating the reflect aligned light rays through a movable focusing lens to form an intermediate image based on the reflected aligned light rays; e) reflecting, by a second movable reflection mirror, the intermediate image to form a reflected intermediate image; 1) projecting, by a movable404925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) projection lens, a final image onto curable resin located on a projection plane; and g) developing a curable resin to form a portion of a 3D object after exposure to the final image.

[0222] Now that embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon can become readily apparent to those skilled in the art. Accordingly, the exemplary embodiments of the present invention, as set forth above, are intended to be illustrative, not limiting. The spirit and scope of the present invention is to be construed broadly.REFERENCES[1] D. Chen, X. Zheng, Multi-material additive manufacturing of metamaterials with giant, tailorable negative Poisson’s ratios, Scientific reports 8(1) (2018) 1-8.[2] Z. Xu. R. Hensleigh, N.J. Gerard, H. Cui, M. Oudich, W. Chen, Y. Jing, X.R. Zheng, Vat photopolymerization of fly-like, complex micro-architectures with dissolvable supports, Addit Manuf 47 (2021) 102321.[3] D. Behera, S. Chizari, L.A. Shaw, M. Porter, R. Hensleigh, Z. Xu, N.K. Roy, L.G. Connolly, X.R. Zheng. S. Saha, Current challenges and potential directions towards precision microscale additive manufacturing-Part II: Laser-based curing, heating, and trapping processes, Precision Engineering 68 (2021) 301-318.[4] D. Behera, S. Chizari, L.A. Shaw, M. Porter, R. Hensleigh, Z. Xu, X. Zheng, L.G. Connolly, N.K. Roy, R.M. Panas, Current challenges and potential directions towards precision microscale additive manufacturing-Part IV: Future perspectives, Precision Engineering 68 (2021) 197-205.[5] M P. Lee, G J. Cooper, T. Hinkley, G.M. Gibson, M.J. Padgett, L. Cronin, Development of a 3D printer using scanning projection stereolithography, Scientific reports 5(1) (2015) 9875.[6] M.M. Emami, F. Barazandeh, F. Yaghmaie, Scanning-projection based stereolithography: Method and structure, Sensors and Actuators A: Physical 218 (2014) 116- 124.[7] V. Meenakshisundaram, L.D. Sturm, C.B. Williams, Modeling A scanning-mask projection vat photopolymerization system for multiscale additive manufacturing. Journal of Materials Processing Technology 279 (2020) 116546.[8] X. Zheng, W. Smith, J. Jackson, B. Moran, H. Cui, D. Chen, J. Ye, N. Fang, N. Rodriguez, T. Weisgraber, Multiscale metallic metamaterials, Nature materials 15(10) (2016) 1100-1106.414925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)[9] J. Wang, A. Papathanasopoulos, Y. Rahmat-Samii, R. Hensleigh, Z. Xu, X. Zheng, Ultra-lightweight transmitarray antenna enabled by charge-programmed three-dimensional multi-material printing, 2022 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM), IEEE, 2022, pp. 293-294.

[0010] J. Wang, R. Hensleigh, Z. Xu, Z. Wang, X. Zheng, Y. Rahmat-Samii, Fully 3D- Printed Lightweight Combination of a Circularly Polarized Transmitarray and a Feed Hom, 2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S / URSI), IEEE, 2022, pp. 645-646.

[0011] X. Zheng, H. Lee, T.H. Weisgraber, M. Shusteff, J. DeOtte, E.B. Duoss, J.D. Kuntz, M.M. Biener, Q. Ge, J.A. Jackson, Ultralight, ultrastiff mechanical metamaterials, Science 344(6190) (2014) 1373-1377.

[0012] Z. Xu, C.S. Ha, R. Kadam, J. Lindahl, S. Kim, H.F. Wu, V. Kune, X. Zheng, Additive manufacturing of two-phase lightweight, stiff and high damping carbon fiber reinforced polymer microlattices, Addit Manuf 32 (2020) 101106.

[0013] P.P. Indurkar, A. Shaikeea, Z. Xu, H. Cui, X. Zheng, V. Deshpande, The coupled strength and toughness of interconnected and interpenetrating multi -material gyroids, MRS Bulletin 47(5) (2022) 461-473.

[0014] M.-T. Hsieh, C.S. Ha, Z. Xu, S. Kim, H.F. Wu, V. Kune, X. Zheng, Stiff and strong, lightweight bi-material sandwich plate-lattices with enhanced energy' absorption, Journal of Materials Research 36(18) (2021) 3628-3641.

[0015] Y. Li, W. Li, T. Han, X. Zheng, J. Li, B. Li, S. Fan, C.-W. Qiu, Transforming heat transfer with thermal metamaterials and devices, Nature Reviews Materials 6(6) (2021) 488- 507.

[0016] N.J. Gerard, M. Oudich, Z. Xu, D. Yao, H. Cui, C.J. Naify, A. Ikei, C.A. Rohde, X.R. Zheng, Y. Jing, Three-dimensional trampolinelike behavior in an ultralight elastic metamaterial, Physical Review Applied 16(2) (2021) 024015.

[0017] R.Y. Wu, L. Zhang, L. Bao, L.W. Wu, Q. Ma, G.D. Bai, H.T. Wu, T.J. Cui, Digital metasurface with phase code and reflection-transmission amplitude code for flexible full-space electromagnetic manipulations, Advanced Optical Materials 7(8) (2019) 1801429.

[0018] R. Hensleigh, H. Cui, Z. Xu, J. Massman, D. Yao, J. Berrigan, X. Zheng, Chargeprogrammed three-dimensional printing for multi-material electronic devices, Nature Electronics 3(4) (2020) 216-224.

[0019] H. Cui, D. Yao, R. Hensleigh. H. Lu, A. Calderon, Z. Xu, S. Davaria, Z. Wang, P. Mercier, P. Tarazaga, Design and printing of proprioceptive three-dimensional architected424925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) robotic metamaterials, Science 376(6599) (2022) 1287-1293.

[0020] P.J. Bartolo, Stereolithography: materials, processes and applications, Springer Science & Business Media201 1.

[0021] Nikon, Infinity Optical Systems, 2021. https: / / www.microscopyu.com / microscopy-basics / infinity-optical-systems. (Accessed 07 / 12 2021).

[0022] J. Kirk, Fixed start open traveling salesman problem genetic algorithm in matlab, 2014. http: / / fieesourcecode.net / matlabprojects / 56913 / fixed-start-open-traveling-salesman- problem — genetic-algorithm-in-matlab#.YXzW9LFXqpE. (Accessed 10 / 29 2021).

[0023] Y. Xu, Y. Zhu, Y. Sun, J. Jin, Y. Chen, A vibration-assisted separation method for constrained-surface-based stereolithography, Journal of Manufacturing Science and Engineering 143(5) (2021).

[0024] Y. Pan, H. He, J. Xu, A. Feinerman, Study of separation force in constrained surface projection stereolithography. Rapid Prototyping Journal 23(2) (2017) 353-361.

[0025] C. Zhou, Y. Chen, Z. Yang, B. Khoshnevis, Digital material fabrication using mask-image-projection-based stereolithography, Rapid Prototyping Journal (2013).

[0026] X. Wu, Q. Lian, D. Li, Z. Jin, Tilting separation analysis of bottom-up mask projection stereolithography based on cohesive zone model, Journal of Materials Processing Technology' 243 (2017) 184-196.

[0027] F. Liravi, S. Das, C. Zhou, Separation force analysis and prediction based on cohesive element model for constrained-surface Stereolithography processes, Computer-Aided Design 69 (2015) 134-142.

[0028] A. Maier, R. Schmidt, B. Oswald-Tranta, R. Schledjewski, Non-destructive thermography analysis of impact damage on large-scale CFRP automotive parts, Materials 7(1) (2014) 413-429.

[0029] P. Yeole, A.A. Hassen, S. Kim, J. Lindahl, V. Kune, A. Franc, U. Vaidya, Mechanical characterization of high-temperature carbon fiber-polyphenylene sulfide composites for large area extrusion deposition additive manufacturing, Addit Manuf 34 (2020) 101255.

[0030] S. Kim, G.D. Dreifus, B.T. Beard, A. Glick, A.K. Messing, A.A. Hassen, J.M. Lindahl, P. Liu, T. Smith, J. A. Failla, Graded infill structure of wind turbine blade accounting for internal stress in big area additive manufacturing, Oak Ridge National Lab.(ORNL), Oak Ridge, TN (United States). 2018.

[0031] Q. Ge, Z. Li, Z. Wang, K. Kowsan, W. Zhang, X. He, J. Zhou, N.X. Fang,434925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)Projection micro stereolithography based 3D printing and its applications, Int J Extreme Manuf 2(2) (2020) 022004.

[0032] N.P. Macdonald, J.M. Cabot, P. Smejkal, R.M. Guijt, B. Pauli, M.C. Breadmore, Comparing microfluidic performance of three-dimensional (3D) printing platforms, Analytical chemistry 89(7) (2017) 3858-3866.

[0033] Prusa, Original Prusa MINI+ kit, 2023. https: / / www.prusa3d.com / product / original-prusa-mini-kit-3 / . (Accessed 03 / 03 2023).

[0034] Creality, Creality shop - Ender 3 DIY 3D Printers Kit, 2023. https: / / crealitjAd.shop / . (Accessed 03 / 03 2023).

[0035] E. Jabari, F. Liravi, E. Davoodi, L. Lin, E. Toyserkani, High speed 3D materialjetting additive manufacturing of viscous graphene-based ink with high electrical conductivity, Addit Manuf 35 (2020) 101330.

[0036] X. Shen, H.E. Naguib, A robust ink deposition system for binder jetting and material jetting, Addit Manuf 29 (2019) 100820.

[0037] B. Hayes, T. Hainsworth, R. MacCurdy, Liquid-solid co-printing of multi-material 3D fluidic devices via material jetting. Addit Manuf 55 (2022) 102785.

[0038] T. Inc, Additive production systems, 2023. https: / / www.trumpf.com / en_US / products / machines-systems / additive-production-systems / . (Accessed 03 / 03 2023).

[0039] E. Inc, Systems and materials for additive manufacturing with metals, 2023. https: / / www.eos.info / en / industrial-3d-printer / metal. (Accessed 03 / 03 2023).

[0040] Q. Ge, A.H. Sakhaei, H. Lee, C.K. Dunn, N.X. Fang, M.L. Dunn, Multimaterial 4D printing with tailorable shape memory polymers, Scientific reports 6(1) (2016) 1-11.

[0041] R. Zhang, N.B. Larsen, Stereolithographic hydrogel printing of 3D culture chips with biofunctionalized complex 3D perfusion networks, Lab on a Chip 17(24) (2017) 4273- 4282.

[0042] A.I. Shallan, P. Smejkal, M. Corban, R.M. Guijt, M.C. Breadmore, Cost-effective three-dimensional printing of visibly transparent microchips within minutes, Analytical chemistry' 86(6) (2014) 3124-3130.

[0043] S. Kawata, H.-B. Sun, T. Tanaka, K. Takada, Finer features for functional microdevices, Nature 412(6848) (2001) 697-698.

[0044] K. Takada, H.-B. Sun, S. Kawata, Improved spatial resolution and surface roughness in photopolymerization-based laser nanowriting, Applied Physics Letters 86(7) (2005) 071122.444925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)

[0045] S.K. Saha, D. Wang, V.H. Nguyen, Y. Chang, J.S. Oakdale, S.-C. Chen, Scalable submicrometer additive manufacturing, Science 366(6461) (2019) 105-109.

[0046] Thorlabs, Does collimated light maintain a constant beam diameter out to infinity?, 2023. https: / / www.thorlabs.com / newgrouppage9.cfm?objectgroup_id=14489. (Accessed 03 / 03 2023)

[0047] Y. Wu, H. Su, M. Li, H. Xing, Digital light processing-based multi-material bioprinting: Processes, applications, and perspectives. (n.d.). https : / / doi . org / 10.1002 / j bm. a.37473.

[0048] S. Subedi, S. Liu, W. Wang, S.M.A. Naser Shovon, X. Chen, H.O.T. Ware, Multi-material vat photopolymerization 3D printing: a review of mechanisms and applications, Npj Adv. Manuf. 1 (2024) 1-17. https: / / doi.org / 10.1038 / s44334-024-00005-w.

[0049] D. Han, C. Yang, N.X. Fang, H. Lee, Rapid multi-material 3D printing with projection micro-stereolithography using dynamic fluidic control, Additive Manufacturing 27 (2019) 606-615. https: / / doi.Org / 10.1016 / j.addma.2019.03.031.

[0050] R.F. Quero. D.P. de Jesus, J.A.F. da Silva. Simple modification to allow high- efficiency and high-resolution multi -material 3D-printing fabrication of microfluidic devices. Lab Chip 23 (2023) 3694-3703. https: / / doi.org / 10.1039 / D3LC00356F.

[0051] Z. Wang, J. Wang, Z. Xu, R. Hensleigh, H. Lu, M. Sowers, M.A. Worsley, Y. Rahmat-Samii, X. (Rayne) Zheng, Charge-Programmable Photopolymers for 3D Electronics via Additive Manufacturing, Advanced Functional Materials 34 (2024) 2313839. https: / / doi.org / ! 0. 1002 / adfm.202313839.

[0052] C.-D. Matte, M. Pearson, F. Trottier-Coumoyer, A. Dafoe, T.H. Kwok, Automated storage and active cleaning for multi-material digital-light-processing printer, Rapid Prototyping Journal 25 (2019) 864-874. https: / / doi.org / 10.1108 / RPJ-08-2018-0211.

[0053] J. Cheng, R. Wang, Z. Sun, Q. Liu, X. He, H. Li, H. Ye, X. Yang, X. Wei, Z. Li, B. Jian, W. Deng, Q. Ge, Centrifugal multimaterial 3D printing of multifunctional heterogeneous objects, Nat Commun 13 (2022) 7931. https: / / doi.org / 10.1038 / s41467-022- 35622-6.454925-6100-0046v.l

Claims

Attorney Docket # 00495-0031 (B2025-011)CLAIMS:What is claimed is:

1. A method of 3D printing comprising: a) exposing a first resin in a first vat to light so as to cure a first layer of a three- dimensional obj ect upon a rotary' build stage; b) removing the three-dimensional object from the first vat while still attached to the rotary build stage; c) placing the three-dimensional object in a wash medium within a washing chamber while the three-dimensional object is still attached to the rotary build stage; d) rotating the three-dimensional object within the wash medium; e) exposing the three-dimensional object to ultrasonic waves within the wash medium generated by an ultrasonic generator; f) removing the three-dimensional object from the wash medium; g) exposing a second resin in a second vat to light so as to cure a second layer of the three-dimensional object upon the rotary build stage; h) removing the three-dimensional object from the second vat while still attached to the rotary' build stage; i) placing the three-dimensional object in the wash medium within the washing chamber while the three-dimensional object is still attached to the rotary build stage; j) rotating the three-dimensional object within the wash medium; k) exposing the three-dimensional object to ultrasonic waves within the wash medium generated by an ultrasonic generator; and l) removing the three-dimensional object from the wash medium.

2. The method of claim 1, wherein the wash medium comprises hexane.

3. The method of claim 1, wherein the wash medium comprises water.

4. The method of claim 1, wherein three-dimensional object completes a full rotation within the wash medium.

5. The method of claim 1, wherein the rotational speed of the rotary build stage is between 100 and 1000 rotations per minute.

6. The method of claim 1, wherein the frequency of the ultrasonic waves generated by the ultrasonic generator is 40,000 Hz.

7. The method of claim 1, wherein the first resin and the second resin are different resins.

8. The method of claim 1, wherein the three-dimensional object is a multi -material object.

9. The method of claim 1, wherein the method further comprises:464925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011) m) exposing the first resin in the first vat to light so as to cure a third layer of the three- dimensional object upon a rotary build stage.

10. The method of claim 1, wherein the method further comprises: m) exposing the second resin in the second vat to light so as to cure a third layer of the three-dimensional obj ect upon a rotary' build stage.

11. The method of claim 1, wherein the method further comprises: m) exposing a third resin in a third vat to light so as to cure a third layer of the three- dimensional object upon a rotary' build stage.

12. A 3D printing system comprising: a) a rotary build stage; b) a plurality of vats comprising a first vat and a second vat, each configured to hold a respective resin; c) a projection system configured to project an image so as to cause resin to cure; d) a first washing chamber configured to hold a first wash medium; and e) an ultrasound generator configured to transmit ultrasonic waves within the first washing chamber when filled with the first wash medium.

13. The 3D printing system of claim 12, wherein the 3D printing system further comprises an elevator for raising and lowering the rotary' build stage.

14. The 3D printing system of claim 12, wherein the 3D printing system further comprises one or more motion stages for moving the rotary build stage along a two-dimensional plane.

15. The 3D printing system of claim 12, wherein the plurality' of vats comprises a third vat.

16. The 3D printing system of claim 12, wherein the projection system includes an ultraviolet projector and one or more optical components.

17. The 3D printing system of claim 16, wherein the one or more optical components comprise a mirror for reflecting light from the ultraviolet projector towards one or more of the plurality7of vats.

18. The 3D printing system of claim 16, wherein the 3D printing system further comprises one or more motion stages configured to move one or more of the one or more optical components along a two-dimensional plane.

19. The 3D printing system of claim 16, wherein the 3D printing system further comprises one or more motion stages configured to move the ultraviolet projector along a two- dimensional plane.

20. The 3D printing system of claim 12, wherein the first wash medium comprises hexane.474925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)21. The 3D printing system of claim 12, wherein the first wash medium comprises water.

22. The 3D printing system of claim 12, wherein the 3D printing system further comprises a second washing chamber configured to hold a second wash medium.

23. The 3D printing system of claim 22, wherein the second wash medium comprises hexane.

24. The 3D printing system of claim 22, wherein the second wash medium comprises water.

25. The 3D printing system of claim 12, wherein the 3D printing system further comprises a vat platform, wherein each of the plurality of vats and the first washing chamber sit atop the vat platform.

26. The 3D printing system of claim 25, wherein the 3D printing system further comprises one or more motion stages configured to move the vat platform along a two-dimensional plane.

27. The 3D printing system of claim 25, wherein the 3D printing system further comprises one or more elevators configured to raise and lower the vat platform.

28. The 3D printing system of claim 25, wherein the 3D printing system further comprises at least one rotational stage configured to rotate the vat platform.

29. A scanning projection system comprising: a) an illumination device, configured to emit light rays corresponding to an initial image; b) a collimating lens configured to propagate the tight rays emitted from the illumination device to form aligned tight rays; c) a first movable reflection minor configured to reflect the aligned light rays to form reflected aligned tight rays; d) a movable focusing lens configured to propagate reflected aligned tight rays to form an intermediate image based on the reflected aligned tight rays; e) a second movable reflection mirror configured to reflect the intermediate image to form a reflected intermediate image; and f) a movable projection lens configured to receive the reflected intermediate image and project a final image onto curable resin located on a projection plane.

30. The scanning projection system of claim 29, wherein the resolution of the final image is adjustable by moving the movable projection lens.

31. The scanning projection system of claim 29, wherein the curable resin, after exposure to the final image, develops to generate a portion of a 3D structure.

32. The scanning projection system of claim 29, wherein the illumination device is a light engine including a digital micromirror device.484925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011)33. The scanning projection system of claim 29, wherein the scanning projection system further includes: g) a beam splitter between the collimating lens and the first movable reflection mirror, wherein the beam splitter is configured to receive the aligned tight rays and form split aligned light rays; and h) a camera configured to detect light intensity of the split aligned light rays corresponding to the initial image.

34. The scanning projection system of claim 33, wherein a second initial image is determined based on the detected light intensity.

35. The scanning projection system of claim 29, wherein the illumination device is configured to emit second light rays corresponding to a second initial image.

36. The scanning projection system of claim 29, wherein the movable focusing lens is a tube lens.

37. The scanning projection system of claim 29, wherein the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are mounted on one or more linear motion stages.

38. The scanning projection system of claim 29, wherein the first movable reflection mirror is mounted on a first linear motion stage, and movable focusing lens, the second movable reflection mirror and the movable projection lens are mounted on a second linear motion stage, wherein the second linear motion stage is perpendicular to the first linear motion stage and is mounted on the first linear motion stage.

39. The scanning projection system of claim 29, wherein the location of the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are controlled by a controller.

40. The scanning projection system of claim 29, wherein the projection pixel resolution of the final image is between 10 micrometers and 100 micrometers.

41. A method of 3D printing comprising: a) emitting, by an illumination device, light rays corresponding to an initial image; b) propagating the light rays emitted from the illumination device through the collimating lens to form aligned light rays; c) reflecting, by a first movable reflection mirror, the aligned light rays to form reflected aligned light rays; d) propagating the reflect aligned light rays through a movable focusing lens to form an intermediate image based on the reflected aligned light rays;494925-6100-0046V.1Attorney Docket # 00495-0031 (B2025-011) e) reflecting, by a second movable reflection mirror, the intermediate image to form a reflected intermediate image; f) projecting, by a movable projection lens, a final image onto curable resin located on a projection plane; and g) developing a curable resin to form a portion of a 3D object after exposure to the final image.

42. The method of 3D printing of claim 41, wherein the projection pixel resolution of the final image is adjustable by moving the movable projection lens.

43. The method of 3D printing of claim 41, wherein the illumination device is a light engine including a digital micromirror device.

44. The method of 3D printing of claim 41, wherein between steps (b) and (c) the method further includes: h) splitting, by a beam splitter between the collimating lens and the first movable reflection mirror, the aligned light rays to form second aligned light rays corresponding to the first image; i) detecting, by the beam a camera, light intensity of the second aligned light rays; j) determining, by a first processing device, a second initial image based on the detected light intensity; and k) emitting, by the illumination device, second light rays corresponding to the second initial image.

45. The method of 3D printing of claim 41, wherein the focusing lens is a tube lens.

46. The method of 3D printing of claim 41, wherein the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are mounted on one or more linear motion stages.

47. The method of 3D printing of claim 41, wherein the first movable reflection mirror is mounted on a first linear motion stage, and the movable focusing lens, the second movable reflection mirror and the movable projection lens are mounted on a second linear motion stage.

48. The method of 3D printing of claim 47, wherein the second linear motion stage is perpendicular to the first linear motion stage.

49. The method of 3D printing of claim 47, wherein the second linear motion stage is mounted on the first linear motion stage.504925-6100-0046v.lAttorney Docket # 00495-0031 (B2025-011)50. The method of 3D printing of claim 41, wherein the location of the first movable reflection mirror, first movable focusing lens, second movable reflection mirror, and second movable projection lens are controlled by a controller.

51. The method of 3D printing of claim 41 , wherein the proj ection pixel resolution of the final image is between 10 micrometers and 100 micrometers.514925-6100-0046v.l

Images