Method for additive manufacturing of three-dimensional articles

• US 9,789,541 B2
• Filed: 02/12/2015
• Issued: 10/17/2017
• Est. Priority Date: 03/07/2014
• Status: Active Grant

• Current Assignee: Arcam Ab (Danaher Corporation)
• Original Assignee: Arcam Ab (Danaher Corporation)
• Inventors: Fager, Mattias
• Primary Examiner(s): Dunn, Colleen
• Assistant Examiner(s): Bajwa, Rajinder
• Application Number:
  US14/621,209
• Publication Number:
  US 20150251249A1
• Time in Patent Office: 978 Days
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/32 of the atmosphere, e.g. composition or pressure in a building chamber
• CPC Class Codes: B22F 10/36 of energy beam parameters
• CPC Class Codes: B22F 10/366 Scanning parameters, e.g. hatch distance or scanning strategy
• CPC Class Codes: B22F 10/38 to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures
• CPC Class Codes: B22F 12/45 Two or more
• CPC Class Codes: B22F 12/49 Scanners
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B28B 1/001 Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00
• 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 64/182 in parallel batches
• CPC Class Codes: B29C 64/386 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B29K 2105/251 Particles, powder or granules expandable particles B29K2105/046
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method for forming at least one three-dimensional article through successive fusion of parts of a powder bed, which parts correspond to successive cross sections of the three-dimensional article, the method comprising the steps of: providing a model of the at least one three-dimensional article; applying a first powder layer on a work table; directing a first energy beam from a first energy beam source over the work table causing the first powder layer to fuse in first selected locations according to corresponding models to form a first cross section of the three-dimensional article, where the first energy beam is fusing at least a first region of a first cross section with parallel scan lines in a first direction; varying a distance between two adjacent scan lines, which are used for fusing the powder layer, as a function of a mean length of the two adjacent scan lines.

Claims

1. A method for forming at least one three-dimensional article without introducing either porosities or incomplete fusion therein through successive fusion of parts of a powder bed, which parts correspond to successive cross sections of the three-dimensional article, said method comprising the steps of:

applying a first powder layer on a work table;

determining, via at least one computer processor of a control unit, a length of at least one of two adjacent of two or more parallel scan lines either applied to the first powder layer or to be applied to the first powder layer;

setting, via the at least one computer processor of the control unit, a distance between the two adjacent of two or more parallel scan lines as a function of the determined length, wherein the function of the determined length is such that as the determined length increases;

(a) the distance increases while the determined length is less than a predetermined value, and (b) the distance is a constant value while the determined length is equal to or greater than the predetermined value; and

directing, via the at least one computer processor of the control unit, a first energy beam from a first energy beam source over said work table so as to cause said first powder layer to fuse in first selected locations according to a corresponding model of said at least one three-dimensional article so as to form a first cross section of said three-dimensional article, where said first energy beam is configured to fuse at least a first region of a first cross section either with said two adjacent of said two or more parallel scan lines extending in a first direction and separated by said set distance, or with at least one additional parallel scan line extending in said first direction and separated from said two adjacent of said two or more parallel scan lines by said set distance.

2. The method according to claim 1, wherein said distance is also a function of the sequence of said adjacent scan lines.

3. The method according to claim 2, wherein:

a first set of two adjacent scan lines are separated with a first distance;

a second set of two adjacent scan lines, provided later than said first set of adjacent scan lines, are separated with a second distance; and

said first distance is smaller than said second distance.

4. The method according to claim 1, wherein said distance is determined based upon at least one of:

a function of the mean length of said two adjacent scan lines, a function of the longest of said two adjacent scan lines, or a function of the shortest of said two adjacent scan lines.

5. The method according to claim 1, further comprising the step of keeping at least one of a scan speed, an energy beam power, or an energy beam spot size on said powder layer constant for said two adjacent scan lines.

6. The method according to claim 1, further comprising the step of keeping a time sink and a scan line time constant for each scan line in at least one cross section of said three-dimensional article.

7. The method according to claim 1, wherein said distance between two adjacent scan lines varies at least one of:

linearly as a function of a mean length of said two adjacent scan lines up to said predetermined value, or as a function of the shortest scan line of said two adjacent scan lines up to said predetermined value.

8. The method according to claim 1, wherein said energy beam is at least one of an electron beam or a laser beam.

9. The method according to claim 1, wherein the scan lines in at least one layer of at least one three-dimensional article are straight lines.

10. The method according to claim 1, wherein the scan lines in at least one layer of at least one three-dimensional region are meandering lines.

11. The method according to claim 1, wherein the adjacent scan lines in at least a first region are fused with a first energy beam from a first energy beam source and a second energy beam from a second energy beam source.

12. The method according to claim 11, wherein:

said first energy beam is emanating from a first electron beam source; and

said second energy beam is emanating from a first laser beam source.

13. The method according to claim 11, wherein:

said first energy beam is emanating from a first electron beam source; and

said second energy beam is emanating from a second electron beam source.

14. The method according to claim 11, wherein:

said first energy beam is emanating from a first laser beam source; and

said second energy beam is emanating from a second laser beam source.

15. The method according to claim 11, wherein said first and second energy beams are configured to fuse said adjacent scan lines simultaneously.

16. The method according to claim 1, wherein said distance between two adjacent scan lines varies linearly as a function of a mean length of said two adjacent scan lines up to said predetermined value.

17. The method according to claim 1, wherein said distance between two adjacent scan lines varies linearly as a function of the shortest scan line of said two adjacent scan lines up to said predetermined value.