Apparatus, method, and computer program product for fusing a workpiece

• US 10,058,921 B2
• Filed: 03/14/2018
• Issued: 08/28/2018
• Est. Priority Date: 04/02/2014
• Status: Active Grant

• Current Assignee: Arcam Ab (Danaher Corporation)
• Original Assignee: Arcam Ab (Danaher Corporation)
• Inventors: Backlund, Johan, Lock, Tomas
• Primary Examiner(s): Dunn, Colleen P
• Assistant Examiner(s): BAJWA, RAJINDER S
• Application Number:
  US15/921,401
• Publication Number:
  US 20180200797A1
• Time in Patent Office: 167 Days
• Field of Search: None
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/36 of energy beam parameters
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B23K 15/0013 Positioning or observing workpieces, e.g. with respect to the impact; Aligning, aiming or focusing electronbeams
• CPC Class Codes: B23K 15/0086 welding for purposes other than joining, e.g. built-up welding
• CPC Class Codes: B23K 15/02 Control circuits therefor
• CPC Class Codes: B23K 26/0643 comprising mirrors
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0732 into a rectangular shape
• CPC Class Codes: B23K 26/0736 into an oval shape, e.g. elliptic shape
• CPC Class Codes: B23K 26/0738 into a linear shape
• CPC Class Codes: B23K 26/342 Build-up welding
• CPC Class Codes: B23K 26/702 Auxiliary equipment
• 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: B28B 17/0081 Process control
• 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 64/393 for controlling or regulating additive manufacturing processes
• 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: G02B 27/0911 : Anamorphotic systems
• CPC Class Codes: Y02P 10/25 : Process efficiency

Abstract

Various embodiments of the present invention relate to a method for welding a workpiece comprising the steps of: making a first weld at a first position on said workpiece with a high energy beam, deflecting the high energy beam with at least one deflection lens for making a second weld at a second position on said workpiece, focusing the high energy beam on said workpiece with at least one focusing lens, shaping the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam. The invention is also related to the use of an astigmatism lens and to a method for forming a three dimensional article.

Claims

1. A method for welding a workpiece, said method comprising the steps of:

making a first weld at a first position on said workpiece with a high energy beam;

deflecting the high energy beam with at least one deflection source to make a second weld at a second position on said workpiece;

focusing the high energy beam on said workpiece with at least one focusing lens so as to form a high energy beam spot on said workpiece; and

shaping the high energy beam spot on said workpiece with at least one astigmatism lens so that the shape of the high energy beam spot on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam,

wherein;

a ratio of a length of said high energy beam spot in said parallel direction and a width of said high energy beam spot in said perpendicular direction is varying as a function of the power of said energy beam on said workpiece either during a scan of said high energy beam on said workpiece or between successive scans of said high energy beam on said workpiece; and

the width of said high energy beam spot in said perpendicular direction is a constant value.

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

3. The method according to claim 1, wherein said deflection source is at least one of a tiltable mirror or a tiltable lens.

4. The method according to claim 1, wherein said deflection source is a deflection coil.

5. The method according to claim 1, wherein the ratio of the length of said high energy beam spot in said parallel direction and the width of said high energy beam spot in said perpendicular direction is also varying as a function of a position of said high energy beam on said workpiece.

6. The method according to claim 1, wherein said energy beam spot is at least five (5) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction.

7. The method according to claim 1, wherein said energy beam spot is at least ten (10) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction.

8. The method according to claim 1, wherein a mean spot size on said workpiece in a direction perpendicular to the scanning direction is smaller than a mean spot size on said workpiece in a direction parallel to the scanning direction for one or more of a full scan length, a full cross section, or a full 3-dimensional article.

9. The method according to claim 1, wherein one or more of the steps of deflecting, focusing, and shaping the high energy beam are performed via execution of one or more computer processors.