Method and apparatus for additive manufacturing

• US 9,713,844 B2
• Filed: 12/07/2016
• Issued: 07/25/2017
• Est. Priority Date: 04/18/2013
• Status: Active Grant

• Current Assignee: Arcam Ab (Danaher Corporation)
• Original Assignee: Arcam Ab (Danaher Corporation)
• Inventors: Ackelid, Ulf
• Primary Examiner(s): ZHAO, XIAO SI
• Application Number:
  US15/371,637
• Publication Number:
  US 20170080495A1
• Time in Patent Office: 230 Days
• CPC Class Codes: B05D 3/068 using ionising radiations (gamma, X, electrons)
• CPC Class Codes: B22F 1/18 Non-metallic particles coated with metal
• CPC Class Codes: B22F 10/20 Direct sintering or melting
• 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 12/49 Scanners
• CPC Class Codes: B22F 12/52 Hoppers
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B22F 2202/01 Use of vibrations
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• 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: 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 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: C23C 14/00 Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
• CPC Class Codes: C23C 14/223 specially adapted for coating particles
• CPC Class Codes: C23C 16/00 Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes reactive sputtering or vacuum evaporation C23C14/00
• CPC Class Codes: C23C 16/4417 : Methods specially adapted for coating powder
• CPC Class Codes: Y02P 10/25 : Process efficiency

Abstract

Various embodiments provide a method and apparatus for forming a three-dimensional article through successive fusion of parts of at least one layer of a powder bed provided on a work table in an additive manufacturing machine, which parts corresponds to successive cross sections of the three-dimensional article. The method comprises the steps of: applying a layer of predetermined thickness of powder particles on the work table, applying a coating on at least a portion of the powder particles, which coating is at least partially covering the powder particles, and fusing the powder particles on the work table with an electron beam.

Claims

1. A method for forming a three-dimensional article through successive fusion of parts of at least one layer of a powder bed provided on a work table in a vacuum chamber, which parts corresponds to successive cross sections of the three-dimensional article, said method comprising the steps of:

applying a predetermined thickness of unfused powder particles on said work table in said vacuum chamber;

applying a coating material on at least a portion of said unfused powder particles while said unfused powder particles are inside said vacuum chamber and prior to fusing any portion of said powder particles, wherein said coating material (a) is at least partially covering said unfused powder particles, and (b) has at least one material characteristic that differs from a corresponding material characteristic of the unfused powder particles; and

after applying the coating material, fusing said unfused powder particles on said work table with an energy beam so as to form said at least one layer of said powder bed.

2. The method according to claim 1, wherein said coating material is applied on said unfused powder particles while said pressure in said vacuum chamber is less than 1×

10<sup>−

2</sup> mbar.

3. The method according to claim 1, further comprising the step of vibrating the work table while at least one of applying said coating material on said unfused powder particles or while said unfused powder particles are on said work table.

4. The method according to claim 1, wherein said coating material is applied by a process selected from the group consisting of:

sputtering, chemical vapor deposition, physical vapor deposition, laser ablation, resistive melting of a target, laser beam melting of a target, electron beam melting of a target, and any combination thereof.

5. The method according to claim 1, wherein said at least one material characteristic of the coating material that differs with a corresponding material characteristic of the unfused powder particles is an electrical conductivity of the coating material.

6. The method according to claim 5, wherein said electrical conductivity of the coating material is higher than an electrical conductivity of the unfused powder particles, said higher electrical conductivity of said coating material being configured for increasing the electrical conductivity of the unfused powder particles.

7. The method according to claim 1, wherein said coating material further has at least one material characteristic in common with the material of the unfused powder particles.

8. The method according to claim 1, further comprising the step of changing the material characteristics for at least one layer of the three-dimensional article by providing a predetermined thickness of said coating material on a predetermined portion of said unfused powder particles.

9. The method according to claim 1, wherein:

said unfused powder particles are made of at least one of a ceramic material or a polymer material; and

said coating material is made of an electrically conductive material.

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

11. A method for forming a three-dimensional article through successive fusion of parts of at least one layer of a powder bed provided on a work table in a vacuum chamber, which parts corresponds to successive cross sections of the three-dimensional article, said method comprising the steps of:

applying a predetermined thickness of unfused powder particles on said work table in said vacuum chamber;

applying a coating material on at least a portion of said unfused powder particles while said unfused powder particles are inside said vacuum chamber and prior to fusing any portion of said unfused powder particles, wherein said coating material (a) is at least partially covering said unfused powder particles, and (b) has an electrical conductivity that differs from an electrical conductivity of the unfused powder particles; and

after applying the coating material, fusing said unfused powder particles on said work table with an energy beam so as to form said at least one layer of said powder bed.

12. The method according to claim 11, wherein said coating material is applied on said unfused powder particles while said pressure in said vacuum chamber is less than 1×

10<sup>−

2</sup> mbar.

13. The method according to claim 11, further comprising the step of vibrating the work table while at least one of applying said coating material on said unfused powder particles or while said unfused powder particles are on said work table.

14. The method according to claim 11, wherein said coating material is applied by a process selected from the group consisting of:

sputtering, chemical vapor deposition, physical vapor deposition, laser ablation, resistive melting of a target, laser beam melting of a target, electron beam melting of a target, and any combination thereof.

15. The method according to claim 11, wherein said electrical conductivity of the coating material is higher than an electrical conductivity of the unfused powder particles, said higher electrical conductivity of said coating material being configured for increasing the electrical conductivity of the unfused powder particles.

16. The method according to claim 11, wherein said coating material further has at least one material characteristic in common with the material of the unfused powder particles.

17. The method according to claim 11, further comprising the step of changing the material characteristics for at least one layer of the three-dimensional article by providing a predetermined thickness of said coating material on a predetermined portion of said unfused powder particles.

18. The method according to claim 11, wherein:

said unfused powder particles are made of at least one of a ceramic material or a polymer material; and

said coating material is made of an electrically conductive material.

19. The method according to claim 11, wherein said energy beam is at least one of an electron beam or a laser beam.