Additive layer manufacturing

Patent metadata

Field	Value
Publication number	US-10427247-B2
Application number	US-201314386277-A
Country	US
Kind code	B2
Filing date	Mar 18, 2013
Priority date	Mar 19, 2012
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

Apparatus and a method for forming a metallic component by additive layer manufacturing are provided. The method includes the steps of using a heat source such as a laser to melt the surface of a work piece and form a weld pool; adding wire or powdered metallic material to the weld pool and moving the heat source relative to the work piece so as to progressively form a new layer of metallic material on the work piece; applying forced cooling to the formed layer; stress relieving the cooled layer by applying a peening step, for example with a pulsed laser, and repeating the above steps as required to form the component layer by layer.

First claim

The invention claimed is:

1. A method of forming a metallic component by additive layer manufacturing, the method comprising:
using a heat source at a treatment station to apply heat to a portion of a surface of a work piece in situ, the heat being sufficient to melt said portion of the surface, the heat source being movable relative to the work piece;
adding metallic material to the melted portion in situ using a source of metallic material at the treatment station, the source of metallic material being movable relative to the work piece, and moving the heat source relative to the work piece so as to progressively form a layer of metallic material on the work piece;
applying forced gas cooling to the added layer in situ using a cooling source at the treatment station, the application of the forced gas cooling being at the time of deposition of the added layer onto another portion of the surface of the work piece, the cooling source being movable relative to the work piece, and moving the cooling source relative to the work piece so as to bring the added layer to a state of crystallisation;
depositing a sacrificial covering upon the cooled added layer, the depositing being at the time of deposition of the added layer to another portion of the surface of the work piece;
stress relieving the cooled added layer in situ using a pulsed laser treatment on the sacrificial covering at the treatment station, stress relief of the cooled added layer being at the time of deposition of the added layer onto another portion of the surface of the work piece, the pulsed laser treatment being movable relative to the work piece, and moving the pulsed laser treatment relative to the work piece so as to relieve stress in the cooled added layer; and
repeating the using, adding, applying, and stress relieving as required to form the component.

2. The method as in claim 1 , wherein the additive layer manufacturing method is at least one of: laser blown powder manufacture, laser powder bed manufacture, and wire and arc manufacture.

3. The method as in claim 1 , wherein the stress relieving comprises applying high frequency peening to the cooled layer.

4. An additive layer manufacturing apparatus for manufacturing a metallic component, the apparatus comprising:
a treatment station that is movable relative to a work piece, the treatment station including a heat source movable relative to the work piece, a source of metallic material movable relative to the work piece, a sacrificial deposition source, a cooling source movable relative to the work piece, and a stress reliever movable relative to the work piece;
the heat source configured to melt a portion of a surface of the work piece in situ together with metallic material being fed into the heat source to form an added layer of metallic material on the work piece at the treatment station as the treatment station moves relative to the work piece;
the cooling source configured to apply forced gas cooling to the added layer in situ to cool the added layer to a state of crystallisation at the treatment station as the treatment station moves relative to the work piece, wherein the cooling source is configured to apply forced gas cooling to a first section of the added layer simultaneously with the heat source causing formation of the added layer of metallic material on a second section of the work piece;
the sacrificial deposition source configured to deposit a sacrificial covering upon the cooled added layer, wherein the sacrificial deposition source is configured to deposit the sacrificial covering upon a third portion of the cooled added layer simultaneously with the heat source causing formation of the added layer of metallic material on the second section of the work piece; and
the stress reliever configured to provide pulsed laser treatment to the sacrificial covering in situ so as to relieve stress in the added layer at the treatment station as the treatment station moves relative to the work piece, stress relief of the cooled added layer being at the time of deposition of another added layer onto the portion of the surface of the work piece.

5. The apparatus as in claim 4 , wherein the stress reliever is configured to be applied specifically to the cooled added layer so as to modify the microstructure of the added layer.

6. The apparatus as in claim 4 , wherein the heat source comprises a laser configured to be focused upon the work piece surface, wherein the source of metallic material comprises a powder, and wherein a gas delivery device is configured to deliver gas carrying the metal powder substantially to the focal point of the laser.

7. The apparatus as in claim 4 , wherein the heat source comprises a laser configured to be focused upon the work piece surface, wherein the source of metallic material comprises a powder bed in which the work piece is to be positioned, and wherein the bed is configured to be filled with metallic powder substantially to a level of the work piece surface.

8. The apparatus as in claim 4 , wherein the heat source comprises a welding arc, and wherein the source of metallic material comprises a metallic wire held on a feed, the welding arc being positioned so as to create a weld pool on the surface of the work piece and the feed being configured to feed the wire to the weld pool.

9. The apparatus as in claim 4 , wherein the cooling source comprises cryogenic cooling.

10. The apparatus as in claim 4 , wherein the sacrificial deposition source includes an applicator to deposit the sacrificial covering upon the cooled added layer.

11. The method as in claim 1 , wherein the method is computer-aided.

12. The apparatus as in claim 4 , wherein the heat source comprises a laser configured to be focused upon the work piece surface, and wherein the source of metallic material comprises a powder bed in which the work piece is to be positioned.

13. An additive layer manufacturing apparatus for manufacturing a metallic component, the apparatus comprising:
a treatment station that is movable relative to a work piece, the treatment station including a heat source movable relative to the work piece, a source of metallic material movable relative to the work piece, a sacrificial deposition source, a cooling source movable relative to the work piece, and a stress reliever movable relative to the work piece,
the heat source comprising a laser configured to be focused upon the work piece surface, or a welding arc positioned so as to create a weld pool on the work piece surface, the heat source configured to melt a portion of a surface of the work piece in situ together with metallic material being fed into the heat source to form an added layer of metallic material on the work piece at the treatment station as the treatment station moves relative to the work piece,
the cooling source configured to apply forced gas cooling to the added layer in situ to cool the added layer to a state of crystallisation at the treatment station as the treatment station moves relative to the work piece,
the sacrificial deposition source configured to deposit a sacrificial covering upon the cooled added layer, and
the stress reliever configured to provide pulsed laser treatment to the sacrificial covering in situ so as to relieve stress in the added layer at the treatment station as the treatment station moves relative to the work piece,
wherein the heat source is configured to, during a first time period, melt the portion of the surface of a first portion of the work piece in situ together with metallic material being fed into the heat source,
wherein the cooling source is configured to, during the first time period, apply the forced

Assignees

• Bae Systems Plc

Inventors

• Wescott Andrew David
• Sidhu Jagjit

Classifications

• B22F12/70

  Gas flow means · CPC title

• B22F12/47

  parallel to the deposition plane · CPC title

• B22F12/45

  Two or more · CPC title

• B22F12/43

  pulsed; frequency modulated · CPC title

• B22F12/20

  Cooling means · CPC title