Method and apparatus for additive manufacturing

• US 9,468,973 B2
• Filed: 06/09/2014
• Issued: 10/18/2016
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Arcam Ab (Danaher Corporation)
• Original Assignee: Arcam Ab (Danaher Corporation)
• Inventors: Ljungblad, Ulric
• Primary Examiner(s): Roe, Jessee
• Assistant Examiner(s): KESSLER, CHRISTOPHER S
• Application Number:
  US14/299,887
• Publication Number:
  US 20150004045A1
• Time in Patent Office: 862 Days
• US Class Current: 1/1
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/31 Calibration of process steps or apparatus settings, e.g. before or during manufacturing
• CPC Class Codes: B22F 10/366 Scanning parameters, e.g. hatch distance or scanning strategy
• CPC Class Codes: B22F 12/45 Two or more
• CPC Class Codes: B22F 12/52 Hoppers
• CPC Class Codes: B22F 12/55 Two or more means for feeding material
• CPC Class Codes: B22F 3/003 Apparatus, e.g. furnaces in general F27B
• CPC Class Codes: B22F 3/1035 Liquid phase sintering
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method for forming a three-dimensional article comprising the steps of: applying a model of the three dimensional article, applying a first powder layer on a work table, directing a first electron beam from a first electron beam source over the work table causing the first powder layer to fuse in first selected locations according to the model to form a first cross section of the three-dimensional article, directing a second electron beam from a second electron beam source over the work table, registering at least one setting of the first electron beam source, registering at least one setting of the second electron beam source, correcting the position of the second electron beam depending on the at least one setting of the first electron beam source and the at least one setting of the second electron beam source.

Claims

1. An apparatus 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, the apparatus comprising:

an electronically produced model of the three dimensional article;

a powder distributor configured to provide a first powder layer on a work table;

at least one control unit configured to;

direct a first electron beam from a first electron beam source over the work table causing the first powder layer to fuse in first selected locations according to the model to form a first part of a first cross section of the three-dimensional article;

direct a second electron beam from a second electron beam source over the work table causing the first powder layer to fuse in second selected locations according to the model to form a second part of the first cross section of the three-dimensional article;

register at least one setting of the first electron beam source; and

register at least one setting of the second electron beam source; and

a correcting unit configured to correct the position of the second electron beam depending on the at least one setting of the first electron beam source and the at least one setting of the second electron beam source for aligning a desired second electron beam position according to the model with a real second electron beam position.

2. The apparatus according to claim 1, wherein the at least one control unit comprises at least a first control unit and a second control unit, the first control unit being configured to direct the first electron beam and the second control unit being configured to direct the second electron beam.

3. The apparatus according to claim 2, wherein the electron beam source settings comprises at least one of:

a coil current in at least one beam source coil for at least one of deflecting or shaping at least one of the electron beam or the beam power, an electrostatic lens for at least one of deflecting or shaping the electron beam, or an electrostatic plate for at least one of deflecting or shaping the electron beam.

4. The apparatus according to claim 1, further comprising a storing unit for storing position correcting values for each combination of the at least one setting in the first and second electron beam source.

5. The apparatus according to claim 1, wherein the at least one control unit is further configured to:

register a distance between a first electron beam and a second electron beam;

register an electron beam current of the first and second electron beams;

adjust a position of the first electron beam on the powder layer, where the adjustment is depending on the distance between the first and second electron beams and the beam current of the first and the second beam; and

adjust a position of the second electron beam on the powder layer, where the adjustment is depending on the distance between the first and second electron beams and the beam current of the first and the second beam.

6. The apparatus according to claim 5, wherein the steps of claim 5 are repeated until the actual position of the first and second electron beam is within a predetermined value from the desired position of the first and second electron beam.

7. An apparatus 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, the apparatus comprising:

a computer model of the three dimensional article;

a powder distributor configured for providing a first powder layer on a work table;

a control unit configured to direct a first electron beam from a first electron beam source over the work table causing the first powder layer to fuse in first selected locations according to the model to form a first part of a first cross section of the three-dimensional article;

a control unit configured to direct a second electron beam from a second electron beam source over the work table causing the first powder layer to fuse in second selected locations according to the model to form a second part of the first cross section of the three-dimensional article;

a control unit configured to register at least one setting of the first electron beam source;

a control unit configured to register at least one setting of the second electron beam source; and

a correcting unit configured to correcting the position of the second electron beam depending on the at least one setting of the first electron beam source and the at least one setting of the second electron beam source for aligning a desired second electron beam position according to the model with a real second electron beam position.

8. The apparatus according to claim 7, wherein the control unit which is configured to direct the first electron beam and the control unit which is configured to direct the second electron beam are the same unit.

9. The apparatus according to claim 7, wherein:

the control unit which is configured to register the at least one setting of the first electron beam source and the control unit which is configured to direct the first electron beam are the same unit; and

the control unit which is configured to register the at least one setting of the second electron beam source and the control unit which is configured to direct the second electron beam are the same unit.

10. The apparatus according to claim 7, further comprising:

a control unit configured to register a distance between a first electron beam and a second electron beam;

a control unit configured to register an electron beam current of the first and second electron beams;

a control unit configured to adjust a position of the first electron beam on the powder layer, where the adjustment is depending on the distance between the first and second electron beams and the beam current of the first and the second beam; and

at least one control unit configured to adjust a position of the second electron beam on the powder layer, where the adjustment is depending on the distance between the first and second electron beams and the beam current of the first and the second beam.

11. The apparatus according to claim 10, wherein the at least one control unit is configured to repeat the steps of claim 10 until the actual position of the first and second electron beam is within a predetermined value from the desired position of the first and second electron beam.