Additive layer manufacturing

• US 9,555,475 B2
• Filed: 11/06/2013
• Issued: 01/31/2017
• Est. Priority Date: 11/09/2012
• Status: Active Grant

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Sidhu, Jagjit, Wescott, Andrew David, Potter, Mark Alfred
• Primary Examiner(s): Thomas, Binu
• Application Number:
  US14/440,283
• Publication Number:
  US 20150306665A1
• Time in Patent Office: 1,182 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B22F 10/25 Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS]
• CPC Class Codes: B22F 10/32 of the atmosphere, e.g. composition or pressure in a building chamber
• CPC Class Codes: B22F 10/50 Treatment of workpieces or articles during build-up, e.g. treatments applied to fused layers during build-up
• CPC Class Codes: B22F 10/80 Data acquisition or data processing
• CPC Class Codes: B22F 10/85 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B22F 12/20 Cooling means
• CPC Class Codes: B22F 12/30 Platforms or substrates
• CPC Class Codes: B22F 12/41 characterised by the type, e.g. laser or electron beam
• CPC Class Codes: B22F 12/43 pulsed; frequency modulated
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 12/45 Two or more
• CPC Class Codes: B22F 2007/042 characterised by the layer forming method
• CPC Class Codes: B22F 7/04 with one or more layers not made from powder, e.g. made from solid metal
• CPC Class Codes: B23K 26/34 Laser welding for purposes other than joining
• CPC Class Codes: B23K 26/354 by melting
• CPC Class Codes: B23K 9/04 Welding for other purposes than joining, e.g. built-up welding
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• 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: 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: Y02P 10/25 : Process efficiency

Abstract

Apparatus and a method for forming a metallic component by additive layer manufacturing are provided. The method includes the steps of mounting a work piece (3) to ALM manufacturing apparatus including measuring means in the form of load cells (13, 14) to measure stresses tending to distort the work piece, using a laser heat source (24) to apply heat to a surface (18) of the work piece (3) sufficient to melt it; adding metallic material to the melted surface (18) and moving the heat source (24) relative to the work piece (3) whereby progressively to form a layer (30) of metallic material on it; repeating the above steps as required, whereby progressively to form the component and, while doing so, measuring stresses tending to distort the component with the load cells (13, 14) and, if they are above a predetermined threshold, stress relieving the work piece with means such as a pulsed laser (27) while still mounted to the apparatus to reduce distortion to a predetermined level, and again repeating above steps as required to complete the component. A computer (16) may be included to control the whole process.

Claims

1. An additive layer manufacturing apparatus for forming a metallic component, the apparatus including:

a mount comprising one or more clamps configured to mount a work piece to the apparatus;

a heat source movable relative to the work piece and configured to apply heat to a portion of a surface of the work piece sufficient to melt said portion;

a material delivery system configured to add metallic material to the melted portion whereby progressively to form a layer of metallic material on the work piece;

a stress measuring system forming part of the one or more clamps and configured to measure stresses tending to distort the work piece; and

a stress relieving system configured to apply a force to the work piece so as to relieve stress in the work piece while mounted to the apparatus whereby to reduce distortion of the work piece during forming of the component.

2. The apparatus as in claim 1 in which the stress measuring system is positioned in a region of extremities of the work piece whereby to measure distortion across at least a portion of the work piece.

3. The apparatus as in claim 1 including a cooling system configured to cool the work piece before operation of the stress relieving system.

4. The apparatus as in claim 1 in which the stress relieving system comprises a pulsed laser configured to apply laser peening to the added layer.

5. The apparatus as in claim 1 in which the stress relieving system is configured to apply ultrasonic peening to the added layer.

6. The apparatus as in claim 1 including a computer programmed to control:

the heat source;

the material delivery system;

movement of the heat source relative to the work piece; and

the stress relieving system in dependence upon stresses in the work piece measured by the stress measuring system.