Methods for screening PCD elements for EDM processing and methods for EDM processing such PCD elements

Patent metadata

Field	Value
Publication number	US-9784313-B1
Application number	US-201514962718-A
Country	US
Kind code	B1
Filing date	Dec 8, 2015
Priority date	Jul 28, 2011
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

Methods of screening a polycrystalline diamond element for suitability for electrical discharge machining (“EDM”). The method includes providing a PCD element including a plurality of bonded diamond grains, determining at least one characteristic of the PCD table correlated to electrical conductivity of the PCD element, and EDM the PCD element if the value of the at least one characteristic correlates to an electrical conductivity above a threshold value.

First claim

What is claimed is:

1. A method of fabricating a bearing assembly, the method comprising:
providing a polycrystalline diamond (“PCD”) element including a PCD volume;
determining a plurality of electrical conductivities of the PCD volume; and
brazing the PCD element to a bearing support ring upon determining that an average of the plurality of electrical conductivities is above a threshold value.

2. The method of claim 1 , wherein the PCD volume is formed by placing a layer including of un-bonded diamond particles adjacent to a carbide substrate and subjecting the layer and the carbide substrate to a high-pressure/high-temperature process.

3. The method of claim 1 , further comprising, after brazing the PCD element to the bearing support ring, electro-discharge machining the PCD element to define a bearing surface.

4. A method of fabricating a bearing assembly, the method comprising:
providing a polycrystalline diamond (“PCD”) element including a PCD volume;
determining a plurality of electrical conductivities of the PCD volume including measuring an electrical resistance between a plurality of locations of the PCD volume with an electrical impedance tomography system; and
brazing the PCD element to a bearing support ring upon determining that at least one of the plurality of electrical conductivities is above a threshold value.

5. The method of claim 1 , wherein the threshold value is about 200 S/m.

6. The method of claim 1 , wherein the threshold value is about 500 S/m.

7. The method of claim 1 , wherein the threshold value is about 1000 S/m.

8. The method of claim 1 , wherein the threshold value is about 2000 S/m.

9. The method of claim 1 , wherein the plurality of electrical conductivities of the PCD volume is calculated by measuring a plurality of electrical resistances of the PCD volume and calculating the plurality of electrical conductivities from the measured plurality of electrical resistances.

10. The method of claim 1 , wherein the PCD element includes a substrate and the PCD volume is bonded to the substrate.

11. A method of fabricating a bearing assembly, the method comprising:
providing a polycrystalline diamond (“PCD”) element including a PCD volume, the PCD volume exhibiting a coercivity of about 115 Oe or more and a metal-solvent catalyst content of less than about 7.5% by weight;
determining a plurality of electrical conductivities of the PCD volume;
brazing the PCD element to a bearing support ring upon determining that an average of the plurality of electrical conductivities of the PCD volume is above a threshold value; and
after brazing the PCD element to the bearing support ring, electro-discharge machining the PCD element to define a bearing surface.

12. The method of claim 11 , wherein the bearing surface is convexly curved or concavely curved.

13. A method of fabricating a bearing assembly, the method comprising:
providing a polycrystalline diamond (“PCD”) element including a PCD volume, the PCD volume exhibiting a coercivity of about 115 Oe or more and a metal-solvent catalyst content of less than about 7.5% by weight;
determining a plurality of electrical conductivities of the PCD volume including measuring an electrical resistance between a plurality of locations of the PCD volume with an electrical impedance tomography system;
brazing the PCD element to a bearing support ring upon determining that at least one of the plurality of electrical conductivities of the PCD volume is above a threshold value; and
after brazing the PCD element to the bearing support ring, electro-discharge machining the PCD element to define a bearing surface.

14. The method of claim 11 , wherein brazing the PCD element to a bearing support ring if at least one of the plurality of electrical conductivities is above a threshold value includes brazing the PCD element to the bearing support ring if an average of the plurality of electrical conductivities is above the threshold value.

15. The method of claim 11 , wherein the coercivity is about 115 Oe to about 250 Oe and the PCD volume exhibits a specific magnetic saturation greater than zero G·cm 3 /g to about 15 G·cm 3 /g.

16. The method of claim 15 , wherein the coercivity is about 115 Oe to about 175 Oe and the specific magnetic saturation is about 5 G·cm 3 /g to about 15 G·cm 3 /g.

17. The method of claim 11 , wherein the threshold value is about 200 S/m.

18. The method of claim 11 , wherein the threshold value is about 500 S/m.

19. The method of claim 11 , wherein the threshold value is about 1000 S/m.

20. The method of claim 11 , wherein the PCD element includes a substrate and the PCD volume is bonded to the substrate.

Assignees

• Us Synthetic Corp
• Us Synthetic Corp

Inventors

• Peterson S Barrett

Classifications

• B23K2201/002

  Operations & Transport · mapped topic

• F16C33/043 Primary

  Sliding surface consisting mainly of ceramics, cermets or hard carbon, e.g. diamond like carbon [DLC] · CPC title

• B23K1/0008

  specially adapted for particular articles or work · CPC title

• B23K31/10

  relating to cutting or desurfacing · CPC title

• F16C17/04

  for axial load only · CPC title