Method of repairing a firtree feature with wire electrical discharge machining

Patent metadata

Field	Value
Publication number	US-11208891-B2
Application number	US-201916577321-A
Country	US
Kind code	B2
Filing date	Sep 20, 2019
Priority date	Sep 20, 2019
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

Methods of repairing a part having a firtree-shaped feature requiring rework are disclosed. An embodiment of the method includes receiving the part having the firtree-shaped feature requiring rework. The part is installed in a machine configured for wire electrical discharge machining (EDM). A location of the firtree-shaped feature relative to a datum of the machine is then determined. Wire EDM is performed on the firtree-shaped feature.

First claim

What is claimed is:

1. A method for repairing a part having a firtree-shaped feature requiring rework defined in the part, the method comprising:
receiving the part having the firtree-shaped feature requiring rework, the firtree-shaped feature having a firtree profile and a thickness;
installing the part in a machine configured for wire electrical discharge machining (EDM);
locating the firtree-shaped feature relative to a datum of the machine, locating the firtree-shaped feature including locating an orientation of a surface of the firtree-shaped feature along the thickness of the firtree-shaped feature; and
performing wire EDM on the firtree-shaped feature.

2. The method as defined in claim 1 , wherein locating the firtree-shaped feature relative to the datum of the machine includes locating a position and an orientation of the firtree-shaped feature relative to a reference coordinate system of the machine.

3. The method as defined in claim 1 , wherein performing wire EDM comprises performing a plurality of wire EDM passes in a region of the firtree-shaped feature, the wire EDM passes having a process parameter of different values.

4. The method as defined in claim 3 , wherein the region defines only part of the firtree-shaped feature.

5. The method as defined in claim 3 , wherein the process parameter is a spark energy intensity.

6. The method as defined in claim 1 , wherein:
the surface of the firtree-shaped feature has a projection and a groove; and
locating the orientation of the surface of the firtree-shaped feature along the thickness of the firtree-shaped feature includes locating an orientation of the projection along the thickness of the firtree-shaped feature.

7. The method as defined in claim 1 , wherein:
the firtree-shaped feature has a radial axis that extends through a center of rotation of the part and a radially-inner extremity of the firtree-shaped feature relative to the center of rotation; and
locating the firtree-shaped feature includes locating the radial axis.

8. The method as defined in claim 7 , wherein locating the radial axis includes locating a midpoint between two points on the firtree-shaped feature and on opposite sides of the radial axis.

9. The method as defined in claim 7 , wherein:
the firtree-shaped feature is a slot; and
the two points are in a live rim of the firtree-shaped feature.

10. The method as defined in claim 9 , comprising locating the two points using electrical touching with a wire of the machine.

11. The method as defined in claim 7 , wherein locating the firtree-shaped feature includes locating an intersection between the surface of the firtree-shaped feature and the radial axis.

12. The method as defined in claim 11 , comprising locating the intersection between the surface of the firtree-shaped feature and the radial axis using electrical touching with a wire of the machine.

13. The method as defined in claim 1 , wherein the part is a disc and the firtree-shaped feature is a slot.

14. A method of manufacturing a disc of a bladed rotor, the method comprising:
using a machine configured for wire electrical discharge machining (EDM), machining a firtree-shaped slot in a disc-shaped workpiece using wire EDM, the firtree-shaped slot extending radially inwardly from a periphery of the workpiece, the firtree-shaped slot having a firtree-shaped profile and a thickness;
removing the workpiece from the machine;
after a portion of the firtree-shaped slot requiring rework has been identified, installing the workpiece in the same or another machine configured for wire EDM;
locating the firtree-shaped slot relative to a datum of the same or the other machine, locating the firtree-shaped slot including locating an orientation of a surface of the firtree-shaped slot along the thickness of the firtree-shaped slot; and
performing wire EDM on the portion of the firtree-shaped slot requiring rework.

15. The method as defined in claim 14 , wherein performing wire EDM on the portion of the firtree-shaped slot requiring rework comprises performing a plurality of wire EDM passes on the portion of the firtree-shaped slot requiring rework, the wire EDM passes having a process parameter of different values.

16. The method as defined in claim 15 , wherein the process parameter is a spark energy intensity.

17. The method as defined in claim 14 , wherein:
the firtree-shaped slot has a radial axis that extends through a center of rotation of the bladed rotor and a radially-inner extremity of the firtree-shaped slot relative to the center of rotation;
locating the firtree-shaped slot includes locating a position of the radial axis; and
locating the firtree-shaped slot includes locating an intersection between the firtree-shaped slot and the radial axis.

18. The method as defined in claim 17 , locating the radial axis includes locating a midpoint between two points on the firtree-shaped slot and on opposite sides of the radial axis.

19. A method for repairing a part having a firtree-shaped feature requiring rework defined in the part, the method comprising:
receiving the part having the firtree-shaped feature requiring rework;
installing the part in a machine configured for wire electrical discharge machining (EDM);
locating the firtree-shaped feature relative to a datum of the machine; and
performing wire EDM on the firtree-shaped feature, wherein:
performing wire EDM comprises performing a plurality of wire EDM passes in a region of the firtree-shaped feature, the wire EDM passes having a process parameter of different values; and
the process parameter is a spark energy intensity.

Assignees

• Pratt & Whitney Canada

Inventors

• Ing Visal
• Hardy Ghislain
• Jean Joel

Classifications

• B23H9/10

  Working turbine blades or nozzles · CPC title

• F05D2230/80

  Repairing, retrofitting or upgrading methods · CPC title

• B23H7/02

  Wire-cutting · CPC title

• B23H7/08

  Wire electrodes · CPC title

• F05D2230/10

  by removing material · CPC title