JP2024522725A - 3D PRINTING SYSTEM HAVING WASTE COLLECTION SUBSYSTEM - Google Patents

Abstract

The three-dimensional printing system (2) includes a resin container (6), a fabrication subsystem (26), a waste collection subsystem (28), and a controller (38). The resin container is configured to contain a photocurable resin (8). The fabrication subsystem is configured to form a 3D article (4) by layer-by-layer selective curing of the photocurable resin. The fabrication subsystem includes a build plate (10), a build plate support structure (14), and a vertical movement mechanism (16). The waste collection subsystem is secured to the build plate support structure and configured to capture the partially polymerized resin as the build plate support structure moves upward. The controller is configured to (a) operate the vertical movement mechanism to translate the build plate support structure to a lower position, and (b) operate the vertical movement mechanism to raise the waste collection subsystem through the resin to a position where the partially polymerized resin can be removed from the waste collection subsystem.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional patent application claims priority to U.S. Provisional Patent Application No. 63/215,165, filed June 25, 2021, by Andrew Enslow et al., entitled "3D Printing System with Waste Collection Subsystem," which is incorporated by reference herein under 35 U.S.C. 119(e).

The present disclosure relates to an apparatus and method for the digital fabrication of three-dimensional (3D) articles by layer-by-layer solidification of liquid photocurable build material. More particularly, the present invention relates to a solution to the problem of partially cured photocurable build material accumulating in a resin container.

3D printing systems are widely used for product prototyping and manufacturing. One type of 3D printing system utilizes a process called stereolithography. A typical stereolithography system utilizes a resin container, an imaging system, and a build plate in liquid photocurable resin held by the resin container. Three-dimensional (3D) articles are fabricated layer-by-layer by selectively imaging and solidifying layers of photocurable resin onto the build plate using radiation.

When a 3D article is made, stray radiation can result in unintended partial curing of photocurable resin that is not part of the 3D article. The partial cure tends to propagate through the resin even in the absence of radiation. Over time, the resin becomes unusable and must be replaced at high cost, resulting in wasted material.

In a first aspect of the disclosure, a three-dimensional (3D) printing system is configured to fabricate a three-dimensional 3D article layer-by-layer. In a fabrication mode, the 3D printing system forms a vertical stack of multiple layers by selective polymerization of individual layers. The 3D printing system includes a resin container, a fabrication subsystem, a waste collection subsystem, and a controller. The resin container is configured to contain a photocurable resin. The fabrication subsystem is configured to form a 3D article by selective layer-by-layer curing of the photocurable resin. The fabrication subsystem includes a build plate, a build plate support structure, and a vertical movement mechanism. The waste collection subsystem is attached to the build plate support structure and configured to capture the partially polymerized resin as the build plate support structure moves in an upward direction. The controller is configured to (a) operate the vertical movement mechanism to translate the build plate support structure to a downward position, and (b) operate the vertical movement mechanism to raise the waste collection subsystem upward through the resin to a position where the partially polymerized resin can be removed from the waste collection subsystem. The waste collection subsystem allows for an automated and convenient method for cleaning debris and partially polymerized resin chunks from the resin container.

In one implementation, the resin container has walls that define a generally rectangular lateral container area for containing the photocurable resin. The build plate has a generally rectangular lateral extent that occupies most of the container area with a rectangular gap between the build plate and the container wall. The waste collection subsystem includes an intake located within the rectangular gap. As the build plate rises, a portion of the resin flows into the intake. With a perforated build plate and an intake occupying most of the rectangular gap, and a sufficient upward velocity of the waste collection subsystem, a majority of the resin passing through the build plate will pass through the waste collection subsystem. This implementation thus allows for a high degree of removal of debris and partially polymerized resin.

In another implementation, the waste collection subsystem includes an intake supported along the edge of the build plate and a sieve container supported below the build plate. A conduit connects the intake to the sieve container. The intake is wider than the conduit. Resin enters the intake vertically and then makes a 90 degree turn along the conduit before entering the sieve container. Debris and partially polymerized resin are captured in the sieve container. The conduit includes a check valve to prevent resin from flowing back from the sieve container into the intake. The sieve container can be easily removed and replaced to facilitate removal of debris and partially polymerized resin from the resin container.

In a second aspect of the disclosure, a three-dimensional (3D) printing system is configured to fabricate a three-dimensional 3D article layer-by-layer. The 3D printing system includes a container, a fabrication subsystem, a waste collection subsystem, and a controller. The container is configured to contain a photocurable resin. The container includes at least one wall defining a wall boundary that laterally encloses the photocurable resin. The fabrication subsystem includes a build plate, a build plate support structure, and a vertical translation mechanism. A lateral gap is defined between the build plate and the wall boundary. The waste collection subsystem includes an intake fluidly coupled to a sieve container. The intake is positioned laterally within the gap. The controller is configured to operate the vertical translation mechanism to translate the build plate and the waste collection subsystem upwardly through the photocurable resin and direct a fluid flow of the photocurable resin through the intake and into the sieve container as the build plate rises.

In various implementations, the wall boundary can be circular, elliptical, polygonal, square, rectangular, or irregular. In a particular implementation, the at least one wall includes four walls and the wall boundary is rectangular.

Schematic of a three-dimensional (3D) printing system Schematic plan view of a portion of a 3D printing system. Isometric view of waste collection subsystem Waste Collection Subsystem Cross Section

1 is a schematic diagram of a three-dimensional (3D) printing system 2 for producing a 3D article 4. In describing the system 2, mutually orthogonal axes X, Y, and Z are utilized, alternatively referred to as the X-, Y-, and Z-axes. Axes X and Y are generally horizontal horizontal axes. The Z-axis is a vertical axis generally aligned with a gravity reference. The term "generally" means that the direction or magnitude is not necessarily precise, but is by design. Thus, the term "generally horizontal" means horizontal (perpendicular to the gravity vector) within design and manufacturing tolerances. The term "generally aligned" means aligned within design and manufacturing tolerances.

The 3D printing system 2 includes a resin container 6 for containing a photocurable resin 8. In the illustrated embodiment, the photocurable resin 8 includes, among other things, a monomer, a catalyst, and a filler. The catalyst allows the resin 8 to be solidified and cured by application of radiation, such as blue radiation, violet radiation, or ultraviolet radiation, typically having a wavelength of less than about 450 nanometers (nm). The resin container 6 includes at least one outer vertical wall 7 joined to a bottom wall 9 for containing the resin 8. In the illustrated embodiment, the at least one outer wall 7 can include four outer walls 7 that laterally contain the resin 8 within a rectangular area. Alternatively, the at least one outer wall 7 can be a single wall that defines an elliptical, circular, or other closed shape for containing the resin 8.

The system 2 includes a build plate 10 having an upper surface 12 on which the 3D article 4 is formed. A build plate support structure 14 supports the build plate 10. A vertical movement mechanism 16 is operable to vertically position the build plate support structure 14, and thus the build plate 10. In one embodiment, the vertical movement mechanism 16 includes a stationary motor coupled to a lead screw. The build plate support structure 14 includes a threaded bearing that receives the lead screw. As the motor rotates the lead screw, the build plate support structure 14 is translated up and down.

System 2 includes a material coating subsystem 18 configured to apply a thin layer of resin to the top surface 12 of the build plate 18 or the 3D article 4. In one embodiment, the material coating subsystem 18 includes a rubber wiper that translates along the lateral Y-axis. The material coating subsystem 18 may include a lateral motion mechanism such as a lead screw (similar to that described for the vertical motion mechanism 16) or a motor-driven belt that provides movement and positioning of the wiper along Y. Such lateral motion mechanisms are known in the art for applications such as conventional scanners and printers.

System 2 includes an imaging subsystem 20 for selectively curing a layer of photocurable resin 8 in a build plane 22. In the illustrated embodiment, imaging system 20 generates a radiation beam 24 that scans along build plane 22. Imaging system 20 includes a laser that generates radiation beam 24 and a pair of galvanometer mirrors for scanning the radiation beam across build plane 22 along X and Y. Build plate 10, build plate support structure 14, vertical motion mechanism 16, material coating subsystem 18, and imaging subsystem 20 are collectively referred to as a fabrication subsystem 26.

The system 2 includes a waste collection subsystem 28 configured to remove partially polymerized material and debris from the photocurable resin 8 during the upward movement of the build plate 10. The waste collection subsystem 28 is mechanically coupled to the build plate support structure 14. The waste collection subsystem 28 includes an intake 30 disposed proximate an edge 32 of the build plate 10. The waste collection subsystem 28 includes a conduit 34 fluidly coupling the intake 30 to a sieve container 36.

The controller 38 includes a processor 40 coupled to a non-volatile or non-transitory information storage device 42. The processor 40 may alternatively be referred to as a processing unit (PU) or a central processing unit (CPU), as known in the art of computing technology. The non-transitory information storage device 42 may include one or more of flash memory and other mass storage devices, such as magnetic disk drives, both of which are known in the art of computing technology. The storage device 42 stores software instructions. The controller 38 is configured to operate the fabrication subsystem 26 when the processor 40 executes the software instructions.

The controller 38 is configured to remove polymerized material and debris from the vessel 6 by the following operations: (A) the controller 38 operates the vertical movement mechanism 16 to lower the waste collection subsystem 28 into the vessel 6. This may be part of the fabrication process or may be solely for the purpose of operating the waste collection subsystem 28. (B) the controller 38 operates the vertical movement mechanism 16 to raise the waste collection subsystem 28. As the waste collection subsystem 28 rises, the photocurable resin 8 enters the inlet 30, passes through the conduit 34, and through the sieve vessel 36. Chunks and debris of partially polymerized material are captured and accumulated in the sieve vessel 36. (C) the waste collection subsystem 28 is raised, allowing the sieve vessel 36 to be removed and replaced as needed.

The controller 38 is configured to create or manufacture the 3D article 4 by the following steps: (a) the controller 38 operates the vertical movement mechanism 16 to position the top surface 12 (of the build plate 10 or a previously imaged portion of the 3D article 4) proximate to the build plane 22; (b) the controller 38 operates the coating subsystem 18 to form a new layer of photocurable resin 8 on the top surface 12; (c) the controller 38 operates the imaging subsystem 20 to selectively cure and solidify the new layer of photocurable resin 8; and repeating (a)-(c) to complete the manufacture of the 3D article 4.

2 is a schematic plan view of a portion of the system 2. At least one wall 7 has an inner surface 43 that contacts the resin 8, thus defining a wall boundary 44 around the resin 8. In the illustrated embodiment, there are four inner surfaces 43 that define a generally rectangular lateral container area 46 for receiving the photocurable resin 8. A rectangular gap 48 is defined laterally between the wall boundary 44 and the build plate 10. An intake 30 of the waste collection subsystem 28 is disposed within the rectangular gap 48. As the waste collection subsystem 28 is raised through the container 6, a majority of the resin 8 flows into the intake 30, allowing for efficient removal of partially polymerized resin material and debris. In the illustrated embodiment, the intake 30 has a major axis that is generally aligned with the X-axis and the major axis of the rectangular gap 48.

In alternative embodiments, at least one wall 7 defines a one-sided wall boundary 44 having a circular, elliptical, or some other continuous shape. In other alternatives, the wall boundary 44 may be triangular, polygonal, or irregularly shaped, thus having two, three, five, six, or more sides. For any of these alternative embodiments, a lateral gap 48 is defined between the wall boundary and the build plate 10. Regardless of shape, the intake 30 of the waste collection subsystem 28 is positioned within the gap 48. The intake 30 can have a lateral geometry that optimally covers a portion of the gap 48. Ideally, the intake 30 matches the geometry of the gap 48 as closely as possible to maximize capture of partially cured resin and debris as the intake 30 translates upward.

3A is an isometric view of a portion of an embodiment of the waste collection subsystem 28. The waste collection subsystem 28 is mechanically coupled to the end and underside of the build plate support structure 14. FIG. 3B is a side cross-sectional view through the waste collection subsystem 28. Between the inlet 30 and the conduit 34 is a bend 50. Arrows 52 indicate the fluid path of the resin 8 as it flows through and out of the waste collection subsystem 28. As the waste collection subsystem 28 is translated upward (+Z) through the resin 8, the resin (a) enters the inlet 30 along the Z axis, (b) flows through a 90 degree bend through the bend 50, (c) flows through the conduit 34 to the sieve vessel 36, and (d) flows through small holes or openings in the sieve vessel 36. In one embodiment, the sieve vessel 36 is a replaceable bag.

The conduit 34 includes a check valve 54. The check valve 54 is configured to open to allow resin flow through the conduit 34 when the waste collection subsystem 28 translates upward, but to close to prevent backflow otherwise. Thus, waste material captured in the sieve vessel 36 does not flow back into the resin vessel 6 when the waste collection subsystem 28 is not translating upward.

The specific embodiments and applications described above are illustrative only and do not exclude modifications and variations encompassed by the appended claims.

Claims (15)

1. A three-dimensional (3D) printing system for producing a 3D article, comprising:
A container configured to contain a photocurable resin;
a fabrication subsystem configured to form the 3D article by layer-by-layer selective curing of the photocurable resin, the fabrication subsystem including a build plate, a build plate support structure, and a vertical translation mechanism;
a waste collection subsystem attached to the build plate support structure and configured to capture partially polymerized resin as the build plate support structure moves in an upward direction; and a controller,
The controller:
activating the vertical translation mechanism to translate the build plate support structure to a lower position;
configured to operate the vertical movement mechanism to raise the waste collection subsystem upward through the resin to a position where partially polymerized resin can be removed from the waste collection subsystem.
Characterized in that
Three-dimensional (3D) printing system. The three-dimensional (3D) printing system of claim 1, characterized in that the container has walls defining a generally rectangular lateral container area for containing the photocurable resin, the build plate has a generally rectangular lateral extent occupying most of the container area with a rectangular gap between the build plate and the container wall, and the waste collection subsystem includes an intake located within the rectangular gap, and a portion of the resin flows into the intake when the build plate is raised. The three-dimensional (3D) printing system of claim 1, wherein the waste collection subsystem includes an intake port supported along an edge of the build plate and a sieve container supported below the build plate, and when the build plate is raised, the resin flows into the intake port and then through the sieve container. The three-dimensional (3D) printing system of claim 3, characterized in that the intake is coupled to a conduit, the intake being relatively wider than the conduit, and the conduit being coupled to the sieve container. The three-dimensional (3D) printing system of claim 3, wherein the waste collection subsystem includes a conduit connecting the inlet to the sieve container, and when the build plate is raised, the resin enters the inlet vertically and then flows laterally from the conduit to the sieve container. The three-dimensional (3D) printing system of claim 3, characterized in that the waste collection subsystem includes a conduit connecting the inlet to the sieve container, the conduit including a check valve to prevent backflow of the resin from the waste collection system when the build plate is not elevated. 1. A method of operating a three-dimensional (3D) printing system configured to manufacture a 3D article, comprising:
A container configured to contain a photocurable resin;
providing a fabrication subsystem configured to form the 3D article by layer-by-layer selective curing of the photocurable resin, the fabrication subsystem including a build plate, a build plate support structure, and a vertical movement mechanism; and a waste collection subsystem attached to the build plate support structure and configured to capture partially polymerized resin as the build plate support structure moves in an upward direction.
operating the vertical translation mechanism to translate the build plate support structure to a lower position; and operating the vertical translation mechanism to raise the waste collection subsystem upward through the resin to a position where partially polymerized resin can be removed from the waste collection subsystem.
A method comprising: 8. The method of claim 7, wherein the container has walls defining a generally rectangular lateral container area for receiving the photocurable resin, the build plate has a generally rectangular lateral extent occupying a majority of the container area with a rectangular gap between the build plate and the container wall, and the waste collection subsystem includes an intake located within the rectangular gap, and a portion of the resin flows into the intake when the build plate is raised. The method of claim 7, wherein the waste collection subsystem includes an intake supported along an edge of the build plate and a sieve container supported below the build plate, and when the build plate is raised, the resin flows into the intake and then through the sieve container. The method of claim 9, wherein the waste collection subsystem includes a conduit connecting the inlet to the sieve vessel, and when the build plate is raised, the resin enters the inlet vertically and then flows laterally from the conduit to the sieve vessel. The method of claim 9, wherein the waste collection subsystem includes a conduit connecting the inlet to the sieve container, the conduit including a check valve to prevent backflow of the resin from the waste collection system when the build plate is not elevated. 1. A three-dimensional (3D) printing system for producing a 3D article, comprising:
a container configured to contain a photocurable resin and including at least one wall defining a wall boundary laterally surrounding said photocurable resin;
a fabrication subsystem configured to form the 3D article by layer-by-layer selective curing of the photocurable resin, the fabrication subsystem including a build plate, a build plate support structure, and a vertical translation mechanism, wherein a gap is defined laterally between the build plate and the wall boundary;
a waste collection subsystem including an intake fluidly coupled to the sieve receptacle, the intake positioned laterally within the gap;
A controller is provided.
The controller:
a vertical translation mechanism configured to operate the build plate and the waste collection subsystem to translate upward through the photocurable resin and direct a fluid flow of the photocurable resin through the intake and into the sieve receptacle as the build plate rises. The three-dimensional (3D) printing system of claim 12, characterized in that the wall boundary is rectangular. The three-dimensional (3D) printing system of claim 12, wherein the waste collection subsystem is supported along an edge of the build plate adjacent the gap. The three-dimensional (3D) printing system of claim 12, characterized in that a check valve is fluidly coupled between the inlet and the sieve container and configured to prevent backflow of resin from the waste collection system when the build plate is not elevated.

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