OPTICAL SENSING TECHNIQUES FOR CALIBRATION OF AN ADDITIVE FABRICATION DEVICE AND RELATED SYSTEMS AND METHODS

• US 20190210289A1
• Filed: 01/09/2018
• Published: 07/11/2019
• Est. Priority Date: 01/09/2018
• Status: Active Grant

• Current Assignee: Formlabs Incorporated
• Original Assignee: Formlabs Incorporated
• Inventors: FrantzDale, Benjamin, Keenan, Justin
• Granted Patent: US 10,611,093 B2
• Time in Patent Office: Days
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates

Abstract

Techniques of optically sensing fiducial targets, such as calibration patterns, within an additive fabrication device are provided. In some embodiments, fiducial targets may be disposed on a structure configured to contact source material of the additive fabrication device, the source material being a material from which the device is configured to fabricate solid objects. Indirect sensing means may be employed such that light emitted from a light source of the additive fabrication device scatters from the surface of a fiducial target. At least some of this scattered light can be measured by a sensor and used to determine a position of the fiducial target. In some embodiments, the fiducial target may be configured to move relative to the light source and/or sensor to provide additional information on the target'"'"'s position via the light scattered from its surface.

Claims

1. An additive fabrication device configured to fabricate an object by forming layers of solid material on a build platform, the solid material being formed from one or more source materials, the additive fabrication device comprising:

at least one light source;

at least one sensor;

a dispenser configured to dispense the one or more source materials into a build region of the additive fabrication device;

a first structure configured to contact the one or more source materials within the build region during said fabrication of the object, wherein a surface of the first structure includes at least a first calibration pattern; and

at least one processor configured to;

direct the at least one light source to the first calibration pattern;

measure, via the at least one sensor, an intensity of light scattered from the first calibration pattern; and

determine a position of the first structure based at least in part on the measured intensity of light.

2. The additive fabrication device of claim 1, wherein the first structure is configured to move relative to the build region, and wherein the at least one processor is further configured to move the first structure during fabrication of the object.

3. The additive fabrication device of claim 1, further comprising a mounting attachment, and wherein the first structure is configured to be removably attached to and detached from the mounting attachment.

4. The additive fabrication device of claim 1, wherein the one or more source materials include a liquid photopolymer, and wherein the first structure is a container configured to hold the liquid photopolymer during fabrication of the object.

5. The additive fabrication device of claim 1, wherein the first structure is the build platform.

6. The additive fabrication device of claim 1, wherein the one or more source materials include a powdered material, and wherein the first structure is configured to contact a surface of the powdered material during fabrication of the object.

7. The additive fabrication device of claim 6, wherein the first structure is mechanically coupled to the dispenser.

8. The additive fabrication device of claim 1, wherein the calibration pattern includes a plurality of surface features having at least two different surface reflectivities.

9. The additive fabrication device of claim 1, further comprising at least one computer readable medium, and wherein the at least one processor is further configured to store a plurality of calibration values in the at least one computer readable medium based at least in part on the determined position of the first structure.

10. The additive fabrication device of claim 9, wherein the plurality of calibration values include a lookup table.

11. The additive fabrication device of claim 1, wherein the at least one light source is configured to produce light at at least one non-visible wavelength.

12. A method of calibrating an additive fabrication device configured to fabricate an object by forming layers of solid material on a build platform, the solid material being formed from one or more source materials, the method comprising:

directing at least one light source of the additive fabrication device onto a first calibration pattern, wherein the additive fabrication device comprises a first structure configured to contact the one or more source materials within the build region during said fabrication of the object, and wherein the first calibration pattern is disposed on a surface of the first structure;

measuring, via at least one sensor of the additive fabrication device, an intensity of light scattered from the first calibration pattern and originating from the at least one light source; and

determining a position of the first structure based at least in part on the measured intensity of light.

13. The method of claim 12, wherein the additive fabrication device further comprises a mounting attachment, and wherein the first structure is configured to be removably attached to and detached from the mounting attachment.

14. The method of claim 12, wherein the one or more source materials include a liquid photopolymer, and wherein the first structure is a container configured to hold the liquid photopolymer during fabrication of the object.

15. The method of claim 12, wherein the first structure is the build platform.

16. The method of claim 12, wherein the one or more source materials include a powdered material, and wherein the first structure is configured to contact a surface of the powdered material during fabrication of the object.

17. The method of claim 16, wherein the first structure is mechanically coupled to the dispenser.

18. The method of claim 12, wherein the calibration pattern includes a plurality of surface features having at least two different surface reflectivities.

19. The method of claim 12, further comprising storing a plurality of calibration values in at least one computer readable medium based at least in part on the determined position of the first structure.

20. The method of claim 12, wherein the at least one light source is configured to produce light at at least one non-visible wavelength.