Selective laser sintering with assisted powder handling

• US 5,053,090 A
• Filed: 07/02/1990
• Issued: 10/01/1991
• Est. Priority Date: 09/05/1989
• Status: Expired due to Fees

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Beaman, Joseph J., Deckard, Carl R.
• Primary Examiner(s): Powell, William A.
• Application Number:
  US07/547,857
• Time in Patent Office: 456 Days
• Field of Search: 156/62.2, 156/89, 156/242, 156/245, 156/272.4, 156/272.8, 219/121.6, 219/121.61, 219/121.63, 219/121.64, 219/121.65, 219/121.66, 219/121.73, 219/121.8, 219/121.85, 264/22, 264/24, 264/26, 264/58, 264/113, 264/125, 264/126, 264/127, 427/53.1, 427/185
• US Class Current: 264/497
• 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 10/366 Scanning parameters, e.g. hatch distance or scanning strategy
• CPC Class Codes: B22F 12/41 characterised by the type, e.g. laser or electron beam
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/49 Scanners
• CPC Class Codes: B22F 12/52 Hoppers
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B23K 26/34 Laser welding for purposes other than joining
• 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: G05B 2219/49013 Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: G05B 2219/49018 Laser sintering of powder in layers, selective laser sintering SLS
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method and apparatus for selectively sintering a layer of powder to produce a part comprising a plurality of sintered layers. The apparatus includes a computer controlling a laser to direct the laser energy onto the powder to produce a sintered mass. The computer either determines or is programmed with the boundaries of the desired cross-sectional regions of the part. For each cross-section, the aim of the laser beam is scanned over a layer of powder and the beam is switched on to sinter only the powder within the boundaries of the cross-section. Powder is applied and successive layers sintered until a completed part is formed. Preferably, the powder is deposited to the target area of the laser and attains high bulk density during sintering.

Claims

1. A method of producing a part comprising the steps of:

depositing powder onto a target surface;

increasing the bulk density of said powder; and

directing an energy beam at the target surface in such a manner that a selected portion of said powder corresponding to a cross-sectional region of the part is sintered by the energy of said beam.

2. The method of claim 1 wherein said step of increasing the bulk density is performed during said directing step.

3. The method of claim 1 wherein said step of depositing comprises:

electrostatically charging said powder; and

dispensing said powder.

4. The method of claim 1 wherein said step of depositing comprises:

electrostatically charging said powder; and

dispensing said powder;

and wherein said step of increasing the bulk density comprises;

producing an electromagnetic field proximate said target surface.

5. The method of claim 1 wherein said powder is polarizable.

6. The method of claim 1 wherein said powder is polarizable;

and wherein said step of increasing the bulk density comprises;

producing an electromagnetic field proximate said target surface.

7. The method of claim 1 wherein said step of depositing comprises:

dispensing said powder with a first electrical charge; and

placing a second electrical charge on said target surface, said first electrical charge being of opposite charge to said second electrical charge.

8. The method of claim 1 wherein said step of depositing comprises:

placing a first electrical charge on a first subportion of said powder;

dispensing said first subportion; and

contouring said dispensed first subportion.

9. The method of claim 1 wherein said step of depositing comprises:

placing a first electrical charge on a first subportion of said powder;

dispensing said first subportion;

contouring said dispensed first subportion;

placing a second electrical charge on a second subportion of said powder; and

dispensing said second subportion;

wherein said first electrical charge is opposite said second electrical charge.

10. The method of claim 1 wherein said powder is magnetic;

and wherein said step of increasing the bulk density comprises producing an electromagnetic field proximate said target surface.

11. The method of claim 1 wherein said powder is polarizable;

and wherein said step of increasing the bulk density comprises producing an electromagnetic field.

12. The method of claim 1 wherein said step of increasing the bulk density comprises directing a fluid stream to said deposited powder.

13. The method of claim 1 wherein said step of increasing the bulk density comprises applying centrifugal force to said deposited powder.