Additive manufacturing method and apparatus

• US 9,718,129 B2
• Filed: 11/18/2013
• Issued: 08/01/2017
• Est. Priority Date: 12/17/2012
• Status: Active Grant

• Current Assignee: Arcam Ab (Danaher Corporation)
• Original Assignee: Arcam Ab (Danaher Corporation)
• Inventors: Wildheim, Martin, Ljungblad, Ulric
• Primary Examiner(s): Johnson, Jonathan
• Assistant Examiner(s): JONES, JEREMY CONRAD
• Application Number:
  US14/443,015
• Publication Number:
  US 20150283610A1
• Time in Patent Office: 1,352 Days
• Field of Search: 419 55
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/52 Hoppers
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• CPC Class Codes: B22F 5/00 Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• CPC Class Codes: B22F 7/02 of composite layers B22F7/002 takes precedence
• 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 64/268 using laser beams; using electron beams [EB]
• CPC Class Codes: B29C 64/386 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method for forming a three-dimensional article, said method comprising the steps of: providing a predetermined amount of powder for forming a first powder layer on a start plate, distributing said predetermined amount of powder with a powder distributor for forming said first powder layer, directing an energy beam over said start plate causing said first powder layer to fuse in selected locations according to a model to form a first cross section of said three-dimensional article. At least one image of the powder to be distributed is captured with a camera at least one time during said distribution of said powder on said start plate for forming said first powder layer and at least one value of at least one parameter in said image detected with said camera is compared with a reference parameter value.

Claims

1. A method for forming a three-dimensional article through successive fusion of parts of a powder bed, which parts corresponds to successive cross sections of the three-dimensional article, said method comprising the steps of:

providing a predetermined amount of powder on a powder table for forming a first powder layer on a surface;

distributing said predetermined amount of powder initially from said powder table to and over said surface for forming said first powder layer on said surface;

directing an energy beam over said first powder layer causing said first powder layer to fuse in selected locations according to a model to form a first cross section of said three-dimensional article;

capturing at least one image of a shape of at least one portion of said predetermined amount of powder that has yet to be initially distributed, said at least one image being captured with a camera at least one time during said initial distribution of another portion of said predetermined amount of powder from said powder table to said surface, said at least one image being captured with the camera prior to distribution of an entirety of all portions of said predetermined amount of powder over said surface and prior to removal of any portions of said predetermined amount of powder from said surface; and

comparing at least one value of at least one parameter in said image detected by said camera with a corresponding reference parameter value,

wherein the at least one parameter is associated with the shape of the at least one portion of said predetermined amount of powder that has yet to be initially distributed.

2. The method according to claim 1, further comprising the step of changing said predetermined amount of powder for forming a second powder layer on top of said first powder layer which is fused in selected locations if at least one parameter value in said image of said powder when forming said first powder layer is deviating at least one Δ

-value from a corresponding reference parameter value.

3. The method according to claim 2, wherein said step of changing said predetermined amount of powder involves at least one of an increase or a decrease in said predetermined amount.

4. The method according to claim 1, further comprising the step of providing a second predetermined amount of powder for forming said first powder layer a second time and distributing said second predetermined amount of powder for forming said first powder layer said second time if at least one parameter value in said image is at least one Δ

-value smaller than a corresponding reference parameter value when forming said first powder layer said first time.

5. The method according to claim 4, wherein said predetermined amount of powder is different than said second predetermined amount of powder.

6. The method according to claim 1, wherein said energy beam is an electron beam.

7. The method according to claim 1, wherein said powder is metallic powder.

8. The method according to claim 1, wherein said image is captured by at least one of an IR-camera, a CCD-camera, a digital camera, a CMOS camera, or a NIR-camera.

9. The method according to claim 1, wherein said parameter in said image may be selected from the group of:

a shape of powder front in front of a powder distributor;

a distance of powder front to a reference position;

a width of powder front; and

a position of powder front.

10. The method according to claim 1, wherein said surface on top of which said first powder layer is provided is at least one of a powder bed or a start plate.

11. The method according to claim 1, wherein said powder table is a powder container with a movable floor for providing said predetermined amount of powder.