EP-4735232-A1 - STEREOLITHOGRAPHY APPARATUS FOR IMPROVING LOCALIZED PLANARITY OF A TRANSPARENT SHEET

Abstract

A 3D printing system includes a machine chassis, a vessel support, a gas pressure source (55), a build vessel, a light engine, and a lateral movement mechanism. The build vessel is supported by the vessel support and includes a transparent sheet (34). The vessel support includes a carriage (52) having a top surface. The carriage is configured to be positioned along a lateral X-axis under the transparent sheet. The carriage defines an optical path and a fluid channel (60) that at least partially surrounds the optical path. The gas pressure source is coupled to the fluid channel. Gas flowing from the gas pressure source and out of the fluid channel is configured to maintain a vertical spacing between the top surface of the carriage and the transparent sheet. The lateral movement mechanism translates and positions the carriage and light engine together along the lateral X-axis.

Inventors

• CLINTON, Nickolas, M.
• SABO, DAVID
• DRAPER, Grant
• ROHRBACH, Samuel, David
• HULL, CHARLES, W.

Assignees

• 3D Systems, Inc.

Dates

Publication Date

20260506

Application Date

20240625

Claims (18)

1. 1 . A three-dimensional (3D) printing system configured to manufacture a 3D article comprising: a machine chassis including a vessel support and a gas pressure source; a build vessel supported by the vessel support, the build vessel including: a vessel base having a central opening; a vessel wall extending upward from the vessel base; and a transparent sheet closing the central opening of the vessel base, the vessel wall and the transparent sheet cooperate to define a fluid reservoir for containing a photocurable fluid; the vessel support or the vessel base including a carriage having a top surface and is configured to be positioned along a lateral X axis under the transparent sheet, the carriage defining: an optical path; and a fluid channel that at least partially surrounds the optical path; the gas pressure source coupled to the fluid channel, gas flowing from the gas pressure source and out of the fluid channel is configured to maintain a vertical spacing between the top surface of the carriage and the transparent sheet; a light engine configured to selectively transmit radiation through the optical path and to a build plane that is above the transparent sheet; and a lateral movement mechanism configured to position the carriage and the light engine along the lateral X axis, the carriage and the light engine are configured to move together with respect to the lateral X axis.
2. 2. The three-dimensional (3D) printing system of claim 1 wherein the vessel base includes a tension ring that presses downward and laterally tensions the transparent sheet, the tension ring laterally surrounds the build plane.
3. 3. The three-dimensional (3D) printing system of claim 2 wherein the vessel base defines a recess that laterally surrounds the tension ring and further comprising a support frame disposed within the recess, the support frame clamps a peripheral edge of the transparent sheet.
4. 4. The three-dimensional (3D) printing system of claim 3 wherein the tension ring presses downward along a closed surface of the transparent sheet that is below the peripheral edge of the transparent sheet.
5. 5. The three-dimensional (3D) printing system of claim 1 wherein the lateral movement mechanism is configured to move the light engine along a lateral Y-axis with respect to the carriage, the lateral Y-axis is perpendicular to the lateral X-axis.
6. 6. The three-dimensional (3D) printing system of claim 5 further comprising a build plate coupled to a vertical movement mechanism.
7. 7. The three-dimensional (3D) printing system of claim 6 further comprising a controller configured to: operate the vertical movement mechanism to position a lower face of the build plate or 3D article at the build plane; operate the lateral movement mechanism to sequentially position the carriage and light engine at a series of X-stop positions; at individual X-stop positions, operate the lateral movement mechanism to scan the light engine along the Y-axis; and concurrent with scanning the light engine, operate the light engine to selectively image a column of the build plane at the X-stop position.
8. 8. The three-dimensional (3D) printing system of claim 1 wherein the light engine is stationary with respect to the Y-axis and wherein the light engine spans the build plane along the Y-axis.
9. 9. The three-dimensional (3D) printing system of claim 1 wherein the light engine includes a plurality of light engines arranged along the X-axis.
10. 10. A method of manufacturing a 3D article using the 3D printing system of claim 6 comprising: operating the vertical movement mechanism to position a lower face of the build plate or 3D article at the build plane; operating the lateral movement mechanism to sequentially position the carriage and light engine at a series of X-stop positions; at individual X-stop positions, operating the lateral movement mechanism to scan the light engine along the Y-axis; and concurrent with scanning the light engine, operating the light engine to selectively image a column of the build plane at the X-stop position.
11. 11. A three-dimensional (3D) printing system configured to manufacture a 3D article comprising: a machine chassis including a vessel support and a gas pressure source; a build vessel supported by the vessel support, the build vessel including: a vessel base having a central opening; a vessel wall extending upward from the vessel base; and a transparent sheet closing the central opening of the vessel base, the vessel wall and the transparent sheet cooperate to define a fluid reservoir for containing a photocurable fluid; the vessel support or the vessel base including a carriage having a top surface and is configured to be positioned along a lateral X-axis under the transparent sheet, the carriage defining: an optical path; and a fluid channel that at least partially surrounds the optical path; the gas pressure source coupled to the fluid channel, gas flowing from the gas pressure source and out of the fluid channel is configured to maintain a vertical spacing between the top surface of the carriage and the transparent sheet; a build plate coupled to a vertical movement mechanism; a projector configured to selectively transmit radiation through the optical path and to a build plane that is above the transparent sheet; a lateral movement mechanism configured position the carriage and projector together along the lateral X-axis and to scan the projector relative to the carriage along a lateral Y-axis that is perpendicular to the lateral X-axis; and a controller programmed to operate the projector and the lateral movement mechanism.
12. 12. The three-dimensional (3D) printing system of claim 11 wherein the vessel base includes a tension ring that presses downward and laterally tensions the transparent sheet, the tension ring laterally surrounds the build plane.
13. 13. The three-dimensional (3D) printing system of claim 12 wherein the vessel base defines a recess that laterally surrounds the tension ring and further comprising a support frame disposed within the recess, the support frame clamps a peripheral edge of the transparent sheet.
14. 14. The three-dimensional (3D) printing system of claim 13 wherein the tension ring presses downward along a closed surface of the transparent sheet that is below the peripheral edge of the transparent sheet.
15. 15. The 3D printing system of claim 11 wherein the controller is configured to operate the vertical movement mechanism, the lateral movement mechanism, and the projector to form a plurality of N layers that form the 3D article, for individual layers: operate the vertical movement mechanism to position a lower face of the build plate or 3D article at the build plane; and operate the lateral movement mechanism position the carriage and the projector at a sequence of positions along the lateral X-axis, at individual positions: operate the lateral movement mechanism to scan the projector along the lateral Y-axis under a portion of the optical path; and concurrent with scanning the projector, operate the projector to selectively harden the photocurable liquid at the build plane and along the portion of the optical path.
16. 16. The three-dimensional (3D) printing system of claim 11 wherein the light engine includes a plurality of light engines arranged along the X-axis.
17. 17. A method of manufacturing a 3D article using the 3D printing system of claim 11 comprising: forming a plurality of N layers that form the 3D article, for individual layers: operating the vertical movement mechanism to position a lower face of the build plate or 3D article at the build plane; and operating the lateral movement mechanism position the carriage and the projector at a sequence of positions along the lateral X-axis, at individual positions: operating the lateral movement mechanism to scan the projector along the lateral Y-axis under a portion of the optical path; and concurrent with scanning the projector, operating the projector to selectively harden the photocurable liquid at the build plane and along the portion of the optical path.
18. 18. A three-dimensional (3D) printing system configured to manufacture a 3D article comprising: a machine chassis including a vessel support and a gas pressure source; a build vessel supported by the vessel support, the build vessel including: a vessel base having a central opening; a vessel wall extending upward from the vessel base; a transparent sheet closing the central opening of the vessel base, the vessel wall and the transparent sheet cooperate to define a fluid reservoir for containing a photocurable fluid; and a carriage having a top surface and is configured to be positioned along a lateral X axis under the transparent sheet, the carriage including: an optical closed by a transparent plate; and a fluid channel flu id ically coupled to the gas pressure source and that at least partially surrounds the optical path; a light engine configured to selectively transmit radiation through the optical path and to a build plane that is above the transparent sheet; a lateral movement mechanism configured to position the carriage and the light engine along the lateral X axis, the carriage and the light engine move together with respect to the lateral X axis; a build plate coupled to the vertical movement mechanism; and a controller programmed to: operate the vertical movement mechanism to position a lower face of the build plate or the 3D article at the build plane; operate the lateral movement mechanism to scan or sequentially step the carriage and the light engine in tandem along the X-axis; concurrent with operating the lateral movement mechanism, operate the light engine to selectively irradiate pixels over the build plane; and repeat operating the vertical movement mechanism, the lateral movement mechanism, and the light engine to complete fabrication of the 3D article in a layer-by-layer manner while gas flowing from the gas pressure source and through the fluid channel maintain a spacing between the carriage and the transparent sheet.

Description

Stereolithography Apparatus for Improving Localized Planarity of a Transparent Sheet Cross-Reference to Related Applications [0001] This non-provisional patent application claims priority to U.S. Provisional Application Serial Number 63/510,957, Entitled “Stereolithography Apparatus for Improving Planarity of a Transparent Sheet” by Nickolas M. Clinton et al., filed on June 29, 2023, incorporated herein by reference under the benefit of U.S.C. 119(e). Field of the Invention [0002] The present disclosure concerns an apparatus and method for manufacture of solid three dimensional (3D) articles from radiation curable materials in a layer-by-layer manner. More particularly, the present disclosure concerns an improved mechanism for obtaining high resolution 3D articles by a local control of flatness of a transparent sheet which forms part of an optical path. Background [0003] Three dimensional (3D) printers are in rapidly increasing use for manufacturing customized 3D articles. One class of 3D printers includes stereolithography printers having a general principle of operation including the selective curing and hardening of radiation curable (i.e. , photocurable) liquids. One type of stereolithography system includes a containment vessel holding the photocurable liquid, a movement mechanism coupled to a support tray, and a light engine. The stereolithography system manufactures or fabricates a 3D article by selectively curing layers of the photocurable liquid along a build plane above a transparent sheet. There is a desire to produce articles having features sizes that are 10 microns or smaller in size. One challenge is the weight of a column of photocurable liquid distorting the transparent sheet which in turn impacts dimensional accuracy of a 3D article due to resultant variations in the optical path from light engine to build plane. Summary [0004] In a first aspect of the disclosure, a three-dimensional (3D) printing system is configured to manufacture a 3D article. The 3D printing system includes a machine chassis, a build vessel, a light engine, and a lateral movement mechanism. The machine chassis includes a vessel support and a gas pressure source. The build vessel is supported by the vessel support and includes a vessel base, a vessel wall, and a transparent sheet. The vessel base has a central opening. The vessel wall extends upward from the vessel base. The transparent sheet closes the central opening of the vessel base. The vessel wall and the transparent sheet cooperate to define a fluid reservoir for containing a photocurable fluid. The vessel support includes a carriage having a top surface. The carriage is configured to be positioned along a lateral X-axis under the transparent sheet. The carriage defines an optical path and a fluid channel that at least partially surrounds the optical path. The gas pressure source is coupled to the fluid channel. Gas flowing from the gas pressure source and out of the fluid channel is configured to maintain a vertical spacing between the top surface of the carriage and the transparent sheet. Without the gas flow, the transparent sheet would slide against the top surface of the carriage and potentially scratch or wear a lower surface of the transparent sheet. The light engine is configured to selectively transmit radiation through the optical path and to a build plane that is above the transparent sheet. The lateral movement mechanism translates and positions the carriage and light engine together along the lateral X-axis. [0005] In one implementation the vessel base includes a recess that extends around the tension ring. A support frame clamps a peripheral edge of the transparent sheet. The support frame is mounted within the recess. The transparent sheet extends downward from the support frame, over a lower edge of the tension ring, and laterally between opposing sides of the tension ring. The transparent sheet provides a lower bound for photocurable liquid that is disposed within the build vessel. [0006] In another implementation the lateral movement mechanism is configured to move the light engine along a lateral Y-axis with respect to the carriage. The lateral Y-axis is perpendicular to the lateral X-axis. The 3D printing system also includes a build plate coupled to a vertical movement mechanism and a controller. The controller is configured to: operate the vertical movement mechanism to position a lower face of the build plate or 3D article at the build plane, operate the lateral movement mechanism to sequentially position the carriage and light engine at a series of X-stop positions, at individual X-stop positions, operate the lateral movement mechanism to scan the light engine along the Y-axis, and concurrent with scanning the light engine, operate the light engine to selectively image a column of the build plane and to selectively cure a portion of the photocurable liquid over the column at the X-stop position. [0007] The build plane is defined as