Method for additive manufacturing

Patent metadata

Field	Value
Publication number	US-2017341141-A1
Application number	US-201715495250-A
Country	US
Kind code	A1
Filing date	Apr 24, 2017
Priority date	May 24, 2016
Publication date	Nov 30, 2017
Grant date	—

Abstract

A method for forming a three-dimensional article through successive fusion of parts of a metal powder bed is provided, comprising the steps of: distributing a first metal powder layer on a work table inside a build chamber, directing at least one high energy beam from at least one high energy beam source over the work table causing the first metal powder layer to fuse in selected locations, distributing a second metal powder layer on the work table, directing at least one high energy beam over the work table causing the second metal powder layer to fuse in selected locations, introducing a first supplementary gas into the build chamber, which first supplementary gas comprising hydrogen, is capable of reacting chemically with or being absorbed by a finished three-dimensional article, and releasing a predefined concentration of the gas which had reacted chemically with or being absorbed by the finished three dimensional article.

First claim

We claim:

1 . A method for forming a three-dimensional article through successive fusion of parts of a metal powder bed, which parts corresponds to successive cross sections of the three-dimensional article, the method comprising the steps of:
distributing a first metal powder layer on a work table inside a build chamber, directing at least one high energy beam from at least one high energy beam source over the work table causing the first metal powder layer to fuse in selected locations to form a first cross section of the three-dimensional article, distributing a second metal powder layer on the work table, directing at least one high energy beam over the work table causing the second metal powder layer to fuse in selected locations to form a second cross section of the three-dimensional article, wherein the second layer is bonded to the first layer, introducing a first supplementary gas into the build chamber, which first supplementary gas comprising hydrogen, is capable of reacting chemically with or being absorbed by a finished three-dimensional article, and releasing a predefined concentration of the gas which had reacted chemically with or being absorbed by the finished three dimensional article.

2 . The method according to claim 1 , wherein the predefined concentration of the gas which is released from the finished three-dimensional article is at least 95% of the amount being absorbed or chemically reacted with the finished three-dimensional article.

3 . The method according to claim 1 , wherein the predefined concentration of the gas which is released from the finished three-dimensional article is at least 99% of the amount being absorbed or chemically reacted with the finished three-dimensional article.

4 . The method according to claim 1 , wherein the first supplementary gas is at least one inert gas.

5 . The method according to claim 1 , wherein the first supplementary gas is a gas selected from the group consisting of: deuterium, hydrocarbons, gaseous organic compounds, ammonia, nitrogen, oxygen, carbon monoxide, carbon dioxide, nitrogen, nitrous oxide, helium, Argon, Neon, Krypton, Xenon and/or Radon.

6 . The method according to claim 1 , wherein the metal powder is Ti, Ti-6Al-4V or any other Ti alloy and wherein the first supplementary gas, absorbed by or chemically reacted with the finished three-dimensional article, is capable of hydrogenizing the Ti, Ti-6Al-4V or the Ti alloy.

7 . The method according to claim 1 , wherein the releasing of a predefined concentration of the gas which had reacted chemically with or being absorbed by the three dimensional article is performed by holding the finished three-dimensional article at a predetermined temperature interval for a predefined time interval in the build chamber when a second supplementary gas is introduced into the build chamber or without any supplementary gas introduced into the build chamber.

8 . The method according to claim 7 , wherein the second supplementary gas is free from H2.

9 . The method according to claim 1 , wherein the releasing of a predefined concentration of the gas which had reacted chemically with or being absorbed by the three dimensional article is performed in a post process outside the build chamber.

10 . The method according to claim 9 , wherein the post process is Hot Isostatic Pressing (HIP).

11 . The method according to claim 1 , wherein the high energy beam is either an electron beam or a laser beam.

12 . The method according to claim 1 , wherein the high energy beam is an electron beam and wherein the build chamber is a vacuum chamber.

13 . The method according to claim 1 , wherein one or more of the steps recited therein are computer-implemented.

14 . An apparatus for forming a three-dimensional article through successive fusion of parts of a metal powder bed, which parts corresponds to successive cross sections of the three-dimensional article, the apparatus comprising:
a build chamber; a working table onto which layers of powdery material are to be placed; at least one high energy beam source; and at least one control unit, wherein the apparatus is configured, via the at least one control unit, for:
distributing a first metal powder layer on a work table inside the build chamber,
directing at least one high energy beam from the at least one high energy beam source over the work table causing the first metal powder layer to fuse in selected locations to form a first cross section of the three-dimensional article,
distributing a second metal powder layer on the work table,
directing at least one high energy beam over the work table causing the second metal powder layer to fuse in selected locations to form a second cross section of the three-dimensional article, wherein the second layer is bonded to the first layer,
providing a first supplementary gas into the build chamber, which first supplementary gas comprising hydrogen, is capable of reacting chemically with or being absorbed by a finished three-dimensional article, and
releasing a predefined concentration of the gas which had reacted chemically with or being absorbed by the finished three dimensional article.

15 . The apparatus according to claim 14 , wherein the predefined concentration of the gas which is released from the finished three-dimensional article is at least 95% of the amount being absorbed or chemically reacted with the finished three-dimensional article.

16 . The apparatus according to claim 14 , wherein the first supplementary gas is at least one inert gas.

17 . The apparatus according to claim 14 , wherein the first supplementary gas is a gas selected from the group consisting of: deuterium, hydrocarbons, gaseous organic compounds, ammonia, nitrogen, oxygen, carbon monoxide, carbon dioxide, nitrogen, nitrous oxide, helium, Argon, Neon, Krypton, Xenon and/or Radon.

18 . The apparatus according to claim 14 , wherein the metal powder is Ti, Ti-6Al-4V or any other Ti alloy and wherein the first supplementary gas, absorbed by or chemically reacted with the finished three-dimensional article, is capable of hydrogenizing the Ti, Ti-6Al-4V or the Ti alloy.

19 . The apparatus according to claim 14 , wherein the releasing of a predefined concentration of the gas which had reacted chemically with or being absorbed by the three dimensional article is performed by holding the finished three-dimensional article at a predetermined temperature interval for a predefined time interval in the build chamber when a second supplementary gas is introduced into the build chamber or without any supplementary gas introduced into the build chamber.

20 . The apparatus according to claim 19 , wherein the second supplementary gas is free from H2.

21 . The apparatus according to claim 14 , wherein either:
the high energy beam is either an electron beam or a laser beam; or the high energy beam is an electron beam and the build chamber is a vacuum chamber.

22 . A computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions embodied therein, the computer-readable program code portions comprising at least one executable portion configured for:
distributing a first metal powder layer on a work table inside a build chamber, directing at least one high energy beam from at least one high energy beam source over the work table causing the first metal powder layer to fuse in selected locations to form a

Assignees

• Arcam Ab

Inventors

• Ackelid Ulf

Classifications

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title

• B23K26/342

  Build-up welding · CPC title

• B23K26/126

  in an atmosphere of gases chemically reacting with the workpiece · CPC title

• B23K15/02

  Control circuits therefor · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title