Heating method of electron beam powder bed fusion

Abstract

Additive layer manufacturing and apparatus (1, fig 1) using a charged particle beam, e.g. electron beam (17, fig 1), to fuse metal powder in a powder bed (2, fig 1) by heating a plurality of discrete

Claims

1. A method of additive layer manufacturing using a charged particle beam to fuse powder within a powder bed to form a product layer-by-layer, the method comprising heating a predetermined area of the powder using the charged particle beam, wherein the predetermined area is defined by a plurality of discrete points, and wherein heating the predetermined area comprises:(i) positioning the charged particle beam at each point, respectively, in a first group of the plurality of discrete points to heat the powder at each point in the first group, wherein at least some of the points in the first group are adjacent;(ii) positioning the charged particle beam at least one discrete point away from the first group;(iii) positioning the charged particle beam at each point, respectively, in a second group of the plurality of discrete points to heat the powder at each point in the second group, wherein at least some of the points in the second group are adjacent; and(iv) positioning the charged particle beam at least one discrete point away from the second group;the method further comprising:(v) repeating steps (i) to (iv) for at least one subsequent first and second group, until the charged particle beam has been positioned at every discrete point in the predetermined area.

2. The method of claim 1, wherein the at least one subsequent first group is adjacent to a previous first group and the at least one subsequent second group is adjacent to a previous second group.

3. The method of claim 1 or 2, wherein the predetermined area is divided into a plurality of sub-areas, and the method comprises:performing step (i) in each sub-area of the plurality of sub-areas;performing steps (ii) and (iii) in each sub-area; andperforming steps (iv) and (v) in each sub-area, until the charged particle beam has been positioned at every discrete point in every sub-area of the predetermined area.

4. The method of claim 1 or claim 2, wherein the predetermined area is divided into a plurality of sub-areas, and wherein the method comprises:performing step (i) in a sub-area of the plurality of sub-areas;performing step (ii) to position the charged particle beam in a different subarea of the plurality of sub-areas; andperforming step (iii) in the different sub-area of the plurality of sub-areas.

5. The method of any preceding claim, further comprising repeating steps (i), (ii), (iii), (iv) and (v) until the charged particle beam has been positioned at every discrete point in the predetermined area at least twice.

6. The method of any preceding claim, wherein the plurality of discrete points are regularly spaced in a first direction.

7. The method of any preceding claim, wherein a first point of the second group is spaced apart from a last point of the first group by the at least one discrete point.

8. The method of any preceding claim, wherein the plurality of discrete points defining the predetermined area are arranged in a grid, the grid comprising one or more rows.

9. The method of claim 8, wherein the one or more rows extend in a first direction and wherein each of the one or more rows are offset from one another in a second direction.

10. The method of claim 8 or claim 9, wherein the points in each of the first and / or second group are arranged adjacent to each other in a same row.

11. The method of claim 8 or claim 9, wherein the points in each of the first and / or second group are distributed across two adjacent rows.

12. The method of any preceding claim, wherein step (ii) comprises positioning the charged particle beam a first predetermined number of discrete points away from the first group and step (iv) comprises positioning the charged particle beam a second predetermined number of discrete points away from the second group.

13. The method of claim 12, wherein steps (ii) and (iv) comprise:jumping the charged particle beam at least some of the first and / or second predetermined number of discrete points along a same row, and / orjumping the charged particle beam at least some of the first and / or second predetermined number of discrete points along a next row.

14. The method of claim 12 or 13, wherein the number of points in each group is equal and wherein the first predetermined number of discrete points and the second predetermined number of discrete points is a same predetermined number of discrete points, wherein the same predetermined number is a multiple of the number of discrete points in each group.

15. The method of any preceding claim, wherein the predetermined area of the powder is greater than an area of powder corresponding to a layer of the product to be formed.

16. The method of any preceding claim, further comprising varying one or more of the following parameters:a current of the charged particle beam;a spot size of the charged particle beam;a velocity of the charged particle beam;17. An additive layer manufacturing apparatus comprising means for performing the method of any of claims 1 to 16.

18. A computer-readable storage device storing instructions that, when executed, cause at least one processor of an additive layer manufacturing apparatus to perform the method of any of claims 1 to 16.

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