Three-dimensional printing system optimizing contour formation for multiple energy beams

1. A method of manufacturing a three-dimensional (3D) article comprising:

determining a lateral alignment uncertainty for a system, the system including a powder dispenser for sequentially dispensing individual layers of powder and a fusing apparatus for generating and scanning a plurality of energy beams including a first beam and a second beam to selectively melt the layers of powder, the lateral alignment uncertainty is with respect to at least the first beam and the second beam;

determining a number N of overlapping scans for forming a contour that bounds a hatch pattern, N is an integer at least equal to one, the determination is based at least partly upon the lateral alignment uncertainty;

operating the powder dispenser to dispense a layer of powder; and

operating the fusing apparatus to selectively fuse the powder including:

operating at least the first beam to fuse a first hatch pattern over an area of the layer of powder; and

operating at least the second beam to fuse a contour using the N overlapping scans to form the contour having a contour width that is equal to N times a melt width of a single scan minus a cumulative overlap of the N overlapping scans.

2. The method of claim 1 wherein the plurality of energy beams includes a third beam, the method further comprises operating the third beam to fuse a second hatch pattern over a second area of the layer of powder.

3. The method of claim 1 wherein N is monotonically related to the lateral alignment uncertainty.

4. The method of claim 1 wherein N is proportional to or increasing with the lateral alignment uncertainty.

5. The method of claim 1 wherein N times the melt width of a single scan is at least equal to the lateral alignment uncertainty.

6. A computer-readable storage medium for manufacturing a three-dimensional (3D) article, the computer-readable storage medium being non-transitory and having computer-readable program code portions stored therein that in response to execution by a processor cause a three-dimensional (3D) printing system to:

determine a lateral alignment uncertainty for a system, the system including a powder dispenser for sequentially dispensing individual layers of powder and a fusing apparatus for generating and scanning a plurality of energy beams including a first beam and a second beam to selectively melt the layers of powder, the lateral alignment uncertainty is with respect to at least the first beam and the second beam; and

determine a number N of overlapping scans for forming a contour that bounds a hatch pattern, N is an integer at least equal to one, the determination is based at least partly upon the lateral alignment uncertainty;

operate the powder dispenser to dispense a layer of powder; and

operate the fusing apparatus to selectively fuse the powder including:

operate at least the first beam to fuse a first hatch pattern over an area of the layer of powder; and

operate at least the second beam to fuse a contour using the N overlapping scans to form the contour having a contour width that is equal to N times a melt width of a single scan minus a cumulative overlap of the N overlapping scans.

7. The computer-readable storage medium of claim 6 wherein the plurality of energy beams includes a third beam, execution by the processor further causes three-dimensional (3D) printing system to fuse a second hatch pattern over a second area of the layer of powder.

8. The computer-readable storage medium of claim 6 wherein N is monotonically related to the lateral alignment uncertainty.

9. The computer-readable storage medium of claim 6 wherein N is proportional to or increasing with the lateral alignment uncertainty.

10. The computer-readable storage medium of claim 6 wherein N times the melt width of a single scan is at least equal to the lateral alignment uncertainty.