METHOD OF MANUFACTURING A COMPONENT

• US 20150037599A1
• Filed: 07/22/2014
• Published: 02/05/2015
• Est. Priority Date: 08/02/2013
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: BLACKMORE, Michael Lewis
• Granted Patent: US 10,137,500 B2
• Time in Patent Office: Days
• US Class Current: 428/548
• CPC Class Codes: B22F 10/10 Formation of a green body
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/50 Treatment of workpieces or articles during build-up, e.g. treatments applied to fused layers during build-up
• CPC Class Codes: B22F 10/85 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B22F 12/45 Two or more
• CPC Class Codes: B22F 12/52 Hoppers
• CPC Class Codes: B22F 12/90 Means for process control, e.g. cameras or sensors
• 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 15/002 Devices involving relative movement between electronbeam and workpiece
• CPC Class Codes: B23K 15/0086 welding for purposes other than joining, e.g. built-up welding
• 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
• CPC Class Codes: Y10T 428/12028 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]

Abstract

An additive layer manufacture (ALM) machine generates a first electron beam for selectively melting a layer of metal powder, and a second electron beam for detecting defects in the selectively melted layer once it has solidified. The second electron beam has a lower power than the first electron beam so as to be used to identify any defects without performing further melting. If any defects are detected, they can be removed, for example by re-melting, before the next layer of powder is supplied. The process may be repeated to generate a finished component with good mechanical properties.

Claims

1. A method of manufacturing a component using electron beam melting comprising:

providing a powder layer;

selectively melting at least a part of the powder layer so as to generate a solid layer of the component using a first electron beam;

identifying any defects in the solid layer by scanning the solid layer using a second electron beam; and

repeating the steps of providing the powder layer, selectively melting at least a part of the powder layer, and identifying any defects in the solid layer at least once so as to build up a shape corresponding to the component, wherein

the power of the second electron beam is lower than the power of the first electron beam.

2. A method of manufacturing a component using electron beam melting according to claim 1, wherein the powder layer is a metal powder layer and the solid layer is a solid metallic layer.

3. A method of manufacturing a component according to claim 1, wherein the step of identifying defects in the solid layer comprises detecting back scattered electrons generated by the interaction of the second electron beam with the solid layer.

4. A method of manufacturing a component according to claim 1, further comprising removing any identified defects in the solid layer before providing the next powder layer.

5. A method of manufacturing a component according to claim 4, wherein the step of removing any identified defects comprises using the first electron beam to re-melt at least a part of the solid layer.

6. A method according to claim 4, further comprising repeating the step of identifying any defects in the solid layer by re-scanning at least a part of the solid layer using the second electron beam to confirm that the identified defects have been removed.

7. T A method of manufacturing a component according to claim 1, further comprising storing data relating to the layer scanned by the second electron beam.

8. A method of manufacturing a component according to claim 7, further comprising:

using the stored data to determine whether any defects have been identified at the same position in two or more different solid layers, such defects being recurring defects; and

if any such recurring defects have been identified, adjusting one or more parameters of the selective melting step so as to avoid future recurring defects at that position.

9. A method of manufacturing a component according to claim 1, further comprising generating an image showing any identified defects in the solid layer.

10. A method of manufacturing a component according to claim 1, wherein:

if a defect is identified in the solid layer, the method further comprises making a decision about whether or not to remove any identified defects in the solid layer before providing the next powder layer; and

the decision is based on one or more predetermined criteria.

11. A method of manufacturing a component according to claim 10, wherein the decision is based at least in part on at least one of the size of the defect, the shape of the defect and the position of the defect.

12. A method of manufacturing a component according to claim 10, wherein the decision is taken by a machine.

13. A method of manufacturing a component according to claim 10, wherein the decision is taken by an operator of the machine.

14. A method of manufacturing a component according to claim 1, wherein the intensity of the second electron beam is lower than the intensity of the first electron beam.

19. A component manufactured using a method comprising the steps of claim 1.

15. An additive layer manufacturing machine for manufacturing a component, comprising:

a base plate on which the component is manufactured;

a powder delivery device for delivering successive layers of powder onto the baseplate;

an electron beam source for generating a first electron beam for selectively melting at least a part of the powder layer so as to produce a solid layer;

an electron beam source for generating a second electron beam for scanning the solid layer; and

a backscatter detector for receiving backscattered electrons from the surface of the solid layer resulting from the scan by the second electron beam to identify any defects in the solid layer, wherein;

the second electron beam has a lower power than the first electron beam.

16. An additive layer manufacturing machine according to claim 15, wherein the electron beam source for generating the first electron beam is the same as the electron beam source for generating the second electron beam.

17. An additive layer manufacturing machine according to claim 15, wherein the electron beam source for generating the first electron beam is different to the electron beam source for generating the second electron beam.

18. An additive layer manufacturing machine according to claim 15, wherein the intensity of the second electron beam is lower than the intensity of the first electron beam.

20. A component manufactured using the apparatus of claim 15.