Method and apparatus for build thickness control in additive manufacturing

Patent metadata

Field	Value
Publication number	US-11498283-B2
Application number	US-201916280390-A
Country	US
Kind code	B2
Filing date	Feb 20, 2019
Priority date	Feb 20, 2019
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

A method for forming a part layer by layer using an additive manufacturing apparatus. The additive manufacturing apparatus includes a resin support, a stage, a measuring system, and an actuator configured to change the relative position of the stage and the resin support. The method includes the steps of: performing an additive manufacturing cycle including the following steps: depositing an uncured layer of resin; moving the stage to a target location; curing the uncured layer of resin; and moving the stage away from the target location; repeating the additive manufacturing cycle; performing a measuring process wherein the measuring process includes the following steps: using the measuring system to take a measurement indicative of an actual position of a structure; comparing the actual position of the structure to an expected position of the structure to determine an error; and using the error to modify the target location.

First claim

What is claimed is:

1. A method for forming a part using an additive manufacturing apparatus that includes a resin support configured to support an uncured layer of resin within a build zone, a stage configured to hold a stacked arrangement of one or more cured layers of the resin that form at least a portion of the part, a measuring system, and an actuator configured to change the relative position of the stage and the resin support the method comprising the steps of:
performing an additive manufacturing cycle including the following steps:
depositing an uncured layer of resin;
moving the stage to a target location;
curing the uncured layer of resin; and
moving the stage away from the target location;

repeating the additive manufacturing cycle;
performing a measuring process wherein the measuring process includes the following steps:
using the measuring system to take a measurement indicative of an actual position of a structure;
comparing the actual position of the structure to an expected position of the structure to determine an error; and
using the error to modify the target location,
wherein the measuring system is configured to determine a plane of the structure by measuring a first set of one or more locations after a first cycle and measuring a second set of one or more locations after a second cycle, the second set of one or more locations being different than the first set of one or more locations.

2. The method of claim 1 , wherein the step of performing a measuring process is performed every cycle.

3. The method of claim 1 , wherein the step of using the error is performed every cycle during which a measuring process is performed.

4. The method of claim 1 , wherein a total error is determined utilizing multiple steps of using the measuring system.

5. The method of claim 1 , wherein the structure is one of the following: the stage, a surface of the uncured layer of resin, a surface of the part, or a combination thereof.

6. The method of claim 1 , wherein the structure is the part.

7. The method of claim 1 , wherein the measurement indicative of the actual position of the structure is taken relative a reference location that is positioned on the stage.

8. The method of claim 7 , wherein the reference location is defined by a cured layer of resin.

9. The method of claim 8 , wherein the reference location is defined by the part.

10. The method of claim 8 , wherein the apparatus is configured such that the reference location can be defined by a block that is built on the stage in parallel with the part.

11. The method of claim 10 , wherein the block is a frame positioned around the part.

12. The method of claim 1 , wherein the structure is a surface of the part.

13. The method of claim 12 , further comprising generating a signal indicative of a position of the stage, wherein the signal is feedback utilized by the computer to adjust the height of the stage relative to an expected height.

14. The method of claim 12 , wherein the stage is configured to move an adjusted distance equal to a predetermined layer thickness plus an amount equal to accumulated error.

15. The method of claim 14 , wherein a cured layer of resin is created in a cycle and the stage is configured to move the adjusted distance after a predetermined number of cycles.

16. An additive manufacturing apparatus, comprising:
a resin support that defines a build surface that is configured to support an uncured layer of resin;
a stage configured to hold a stacked arrangement of one or more cured layers of resin that form a part that defines a surface positioned opposite the stage;
a radiant energy apparatus positioned opposite to the stage such that it is operable to generate and project radiant energy in a predetermined pattern;
an actuator configured to change the relative position of the stage and the resin support; and
a measuring system that is configured for measuring the position of one or more structures relative to the resin support, determining an error in the position of the one or more structures, and determining a plane of the one or more structures by measuring a first set of one or more locations after a first cycle and measuring a second set of one or more locations after a second cycle, the second set of one or more locations is different than the first set of one or more locations; and
a controller communicatively coupled to the actuator and the measuring system, the controller programmed to:
receive a signal indicative of the error from the measuring system; and
transmit one or more instructions to the actuator to cause a change in the relative position of the stage and the resin support;

wherein the structure is one of the following: the stage, a surface of the uncured layer of resin, a surface of the part, or a combination thereof.

17. The additive manufacturing apparatus of claim 16 , wherein the measuring system includes a laser rangefinder and the structures to be measured are the surface of the part and the surface of the uncured resin and the measuring system is configured to generate a signal indicative of the position of the surface of the part relative to the surface of the uncured resin and to determine movement of the stage based upon the signal.

18. The additive manufacturing apparatus of claim 17 , wherein the layer of uncured resin is configured to be cured by a first range of light frequencies and the measuring system includes an optical sensor that generates a second range of light frequencies and the second range is different than the first range.

19. The additive manufacturing apparatus of claim 16 , comprising a reference location that is positioned on the stage.

20. A method for forming a part using an additive manufacturing apparatus that includes a resin support configured to support an uncured layer of resin within a build zone, a stage configured to hold a stacked arrangement of one or more cured layers of resin that form at least a portion of the part, a measuring system, and an actuator configured to change the relative position of the stage and the resin support, the method comprising the steps of:
operating the additive manufacturing apparatus in accordance with a build profile to create a cured build layer of a part;
measuring a dimension of the part using the measuring system, wherein the measuring system is configured to determine a plane of the part by measuring a first set of one or more locations after a first cycle and measure a second set of one or more locations after a second cycle, the second set of one or more locations is different than the first set of one or more locations;
determining whether the dimension includes an error;
responding to the determination of an error by modifying the build profile to include a compensation layer wherein the thickness of the compensation layer is chosen to compensate for the error.

21. The method according to claim 20 , further comprising the steps of:
adding the error to an accumulated error value;
determining the thickness of the compensation layer by using the accumulated error value; and
wherein the accumulated error value is developed over multiple cycles.

22. The method according to claim 21 , further comprising the steps of
comparing the accumulated error value to a threshold error value; and
performing the step of creating the compensation layer when the accumulated error value exceeds the threshold error value.

23. The method according to claim 20

Assignees

• Gen Electric

Inventors

• Dubelman Meredith Elissa
• Thompson Mary Kathryn
• Barnhill Christopher
• Yang Xi

Classifications

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C64/393 Primary

  for controlling or regulating additive manufacturing processes · CPC title

• B29C64/106

  using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title