Cutting elements and bits incorporating the same

Abstract

Cutting elements and bits incorporating such cutting elements are provided. The cutting elements have a substrate, a first ultra hard material layer formed over the substrate, and a second ultra hard material layer formed over the first ultra hard material layer. The second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 are cross-sectional views of exemplary embodiment cutting elements of the present invention.

FIG. 5 is a top view of an exemplary embodiment cutting element of the present invention.

FIGS. 6A, 6B and 7-11 are cross-sectional views of other exemplary embodiment cutting elements of the present invention.

FIG. 12 is a front perspective view of an exemplary embodiment cutting element of the present invention with a portion of its cutting layer worn off.

FIGS. 13A and 13B are cross-sectional views of other exemplary embodiment cutting elements of the present invention.

FIG. 14 is a perspective view of a bit incorporating cutting elements of the present invention mounted thereon.

Claims

1. A cutting element comprising: a substrate;a first ultra hard material layer formed over the substrate; anda second ultra hard material layer formed over the first ultra hard material layer, wherein the second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm.

2. A cutting element as recited in claim 1 wherein the second ultra hard material layer has a higher abrasion resistance than an first ultra hard material layer.

3. A cutting element as recited in claim 1 wherein the second ultra hard material layer comprises an average ultra hard material particle size that is smaller than an average ultra hard material particle size of the first ultra hard material layer.

4. A cutting element as recited in claim 1 wherein the second ultra hard material layer is a TSP material layer.

5. A cutting element as recited in claim 1 wherein the second ultra hard material layer is a PCD material layer.

6. A cutting element as recited in claim 1 wherein the second ultra hard material layer is a PCBN material layer.

7. A cutting element as recited in claim 1 wherein the second ultra hard material layer encapsulates the first ultra hard material layer.

8. A cutting element as recited in claim 1 wherein the second ultra hard material layer is formed over only a portion of the first ultra hard material layer.

9. A cutting element as recited in claim 1 wherein the first ultra hard material layer has an upper surface and a peripheral surface having a height and wherein the second ultra hard material layer covers between 50% to 100% of the height of the peripheral surface.

10. A cutting element as recited in claim 1 wherein the thickness of the second ultra hard material layer is not constant.

11. A cutting element as recited in claim 1 wherein a surface of the second ultra hard material layer interfacing with the first ultra hard material layer is non-uniform.

12. A cutting element as recited in claim 1 wherein the first and second ultra hard material layers comprise the same type of ultra hard material.

13. A cutting element as recited in claim 1 wherein the first and second ultra hard material layers are different types of ultra hard material layers.

14. A cutting element as recited in claim 1 wherein the first ultra hard material layer comprises a non-uniform outer surface.

15. A cutting element as recited in claim 1 wherein the first ultra hard material layer comprises a depression and wherein the second ultra hard material layer is within the depression.

16. A cutting element as recited in claim 1 further comprising a third ultra hard material layer formed over the first ultra hard material layer and spaced apart from the second ultra hard material layer, wherein the third ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm.

17. A cutting element as recited in claim 1 wherein the second ultra hard material layer defines a cutting edge of the cutting element to be used for cutting.

18. A cutting element as recited in claim 1 wherein when the second ultra hard material layer wears it forms a scar exposing the first ultra hard material layer and said second ultra hard material layer defines at least a lip having a sharp edge surrounding said scar, wherein the first ultra hard material layer wears faster than the second ultra hard material layer

19. A bit comprising a body and a cutting element as recited in claim 1 mounted on said body.

20. A bit comprising: a body; anda cutting element mounted on the body, the cutting element comprising, a substrate, anda cutting layer formed over the substrate, the cutting layer comprising, a first ultra hard material layer formed over the substrate, anda second ultra hard material layer formed over the first ultra hard material layer, wherein the second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm, wherein said second ultra hard material layer is oriented for making contact with an object to be drilled by said bit.

21. A drill bit as recited in claim 20 wherein the cutting element cutting layer further comprises a third ultra hard material layer formed over the first ultra hard material layer and spaced apart from the second ultra hard material layer, wherein the third ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm.

22. A drill bit as recited in claim 20 wherein the second ultra hard material layer covers the entire first ultra hard material layer.

23. A method for improving the cutting efficiency of a cutting layer comprising; forming a cutting element having a substrate, a first ultra hard material layer over the substrate and a second ultra hard material layer over the first ultra hard material layer, wherein the second ultra hard material layer has a thickness in the range of 0.05 mm to 2 mm, wherein the first ultra hard material layer wears faster than the second ultra hard material layer, wherein said first and second ultra hard material layers define the cutting layer;cutting an object with said cutting layer wearing a portion of the second ultra hard material layer exposing a portion of the first ultra hard material layer defining a wear scar exposing the first ultra hard material layer surrounded by the second ultra hard material layer; andcontinuing cutting said object with said cutting layer causing the inner layer to wear faster than the outer layer forming at least a lip on the outer layer having a cutting edge surrounding the wear scar.

24. The method as recited in claim 23 wherein the scar comprises an area that increases after continuous cutting with said cutting layer.