Cutting tool and method of making the cutting tool

• US 5,722,803 A
• Filed: 07/14/1995
• Issued: 03/03/1998
• Est. Priority Date: 07/14/1995
• Status: Expired due to Term

• Current Assignee: Kennametal Incorporated
• Original Assignee: Kennametal Incorporated
• Inventors: Inspektor, Aharon, Prizzi, John J., Oles, Edward J., Battaglia, Frank B., Cackowski, Vincent J.
• Primary Examiner(s): Rachuba, M.
• Assistant Examiner(s): TSAI, HENRY
• Application Number:
  US08/502,437
• Time in Patent Office: 963 Days
• Field of Search: 407/119, 407/118, 407/115, 51/293
• US Class Current: 407/119
• CPC Class Codes: B23B 2228/08 applied by physical vapour deposition [PVD]
• CPC Class Codes: B23B 2260/072 Grooves
• CPC Class Codes: B23B 27/146 Means to improve the adhesion between the substrate and the coating
• CPC Class Codes: Y10T 407/24 with chip breaker, guide or deflector
• CPC Class Codes: Y10T 407/27 comprising tool of specific chemical composition
• CPC Class Codes: Y10T 408/78 Tool of specific diverse material
• CPC Class Codes: Y10T 408/81 Tool having crystalline cutting edge

Abstract

A coated cutting tool, and a method of producing the same, comprising a substrate which has a roughened surface that presents a surface roughness of between 15 microinches R_a and 125 microinches R_a. A coating is applied to the roughened surface of the substrate by physical vapor deposition. A coated cutting tool having a low cobalt substrate and experiencing long tool life is also discussed.

Claims

1. A coated cutting tool comprising:

a substrate; and

a PVD coating applied directly onto the surface of the substrate, the PVD coating having an adherence as measured by the Rockwell A indentation adhesion load test of greater than or equal to 80 kg.

2. The coated cutting tool of claim 1 wherein the adherence of the PVD coating as measured by the Rockwell A indentation adhesion load test is greater than or equal to 100 kg.

3. The coated cutting tool of claim 1 wherein the PVD coating has a thickness of at least about 3 micrometers on the flank face.

4. The coated cutting tool of claim 1 wherein the PVD coating had a thickness of at least about 3 micrometers on the rake face.

5. The coated cutting tool of claim 1 wherein the coating includes TiAlN.

6. The coated cutting tool of claim 1 wherein the coating includes alumina.

7. The coated cutting tool of claim 1 wherein the coating includes TiC.

8. The coated cutting tool of claim 1 wherein the substrate comprises a hard carbide and binder, the substrate having a binder enriched peripheral layer.

9. The coated cutting tool of claim 1 wherein the substrate has a substantially uniform microstructure.

10. The coated cutting tool of claim 1 wherein the coating includes cubic Boron Nitride.

11. The coated cutting tool of claim 1 wherein the substrate has a rake face and a flank face, an edge being at the joinder of the rake face and the flank face, the substrate having a composition of between 0.2 and 2.9 weight percent Co, and the balance consisting essentially of WC.

12. The coated cutting tool of claim 11 wherein the substrate contains between about 2.3 and about 2.9 weight percent cobalt.

13. A coated cutting tool comprising:

a substrate;

a PVD coating directly on the surface of the substrate, the PVD coating having a thickness of at least 6 micrometers on a selected one of the rake face or the flank face, and the PVD coating having an adherence as measured by the Rockwell A indentation adhesion load test is greater than or equal to 60 kg.

14. The coated cutting tool of claim 13 wherein the substrate comprises a hard carbide and a binder metal, and the substrate having a binder enriched layer near the periphery thereof.

15. The coated cutting tool of claim 13 wherein the substrate has a substantially uniform microstructure.

16. The coated cutting tool of claim 13 wherein the PVD coating has a thickness of between 6 and 15 micrometers, and the adherence of the coating as measured by the Rockwell A indentation adhesion load test is equal to or greater than 60 kg.

17. The coated cutting tool of claim 16 wherein the PVD coating has a thickness of between 6 and 12 micrometers.

18. A coated cutting tool comprising:

a substrate having a rake face and a flank face, an edge being at the joinder of the rake face and the flank face, the substrate having a composition of between 0.2 and 2.9 weight percent Co, and the balance consisting essentially of WC; and

a coating where the outer layer being applied by PVD.

19. The coated cutting tool of claim 18 wherein the coating is a multi-layer coating.

20. The coated cutting tool of claim 19 wherein the coating further includes a base layer of CVD-applied TiN and an intermediate layer of CVD-applied TiCN.

21. The coated cutting tool of claim 19 wherein the coating has an adherence as measured by the Rockwell A indentation adhesion load test of greater than or equal to 45 kg.

22. The coated cutting tool of claim 19 wherein the rake face of the coated cutting tool has a surface roughness of at least about 45 microinches R_a.

23. The coated cutting tool of claim 18 wherein the coating is a single layer.

24. A cutting tool made by powder metallurgical techniques including pressing a powder composition into a green compact, the tool comprising:

a substrate with a rake face and a flank face wherein a cutting edge is at the joinder of the rake face and the flank face; and

the rake face presents a roughened surface formed during the pressing of the green substrate.

25. The cutting tool of claim 24 further including a wear-resistant coating on the rake face and the flank face.

26. The cutting tool of claim 25 wherein the coating is applied by PVD.

27. The cutting tool of claim 25 wherein the coating is applied by CVD.

28. The cutting tool of claim 25 wherein the coating has a first layer applied by CVD and a second layer applied by PVD.

29. The cutting tool of claim 25 wherein the coating is diamond.

30. The cutting tool of claim 24 wherein the rake face includes a structural chip breaker.

31. The cutting tool of claim 24 wherein the flank face presents a surface that is smoother than the rake face.

32. The cutting tool of claim 24 wherein the roughness of the rake surface is between 15 microinches R_a and 125 microinches R_a.

33. The cutting tool of claim 24 wherein the flank face has a surface roughness less than 15 microinches R_a.

34. A cutting tool comprising:

a rake face and a flank face wherein a peripheral edge is at the joinder of the rake face and the flank face; and

the rake face presents a roughened surface formed by mechanical action upon the rake face.

35. The cutting tool of claim 34 further including a wear-resistant coating on the rake face and the flank face.

36. The cutting tool of claim 34 wherein the rake face includes a structural chip breaker.

37. The cutting tool of claim 34 wherein the flank face presents a surface that is smoother than the rake face.

38. A coated cutting tool comprising:

a substantially fully dense substrate having a rake surface and a flank surface, the rake surface of the substrate having a surface roughness of between 15 microinches R_a and 125 microinches R_a ; and

an outer coating applied by physical vapor deposition so that the cutting tool presents a coated rake face and a coated flank face.

39. The coated cutting tool of claim 38 wherein the flank surface of the substrate having a surface roughness of between 15 microinches R_a and 125 microinches R_a.

40. The coated cutting tool of claim 38 wherein the coated rake face has a surface roughness of between 15 microinches R_a and 125 microinches R_a, and the coated flank face has a surface roughness of between 15 microinches R_a and 125 microinches R_a.

41. The coated cutting tool of claim 38 wherein the coated rake face has a surface roughness of between 15 microinches R_a and 125 microinches R_a, and the coated flank face has a surface roughness that is less than the surface roughness of the coated rake face and is less than 25 microinches R_a.

42. The coated cutting tool of claim 38 wherein the coated rake face has a surface roughness less than 25 microinches R_a, and the coated flank face has a surface roughness less than 25 microinches R_a.

43. The coated cutting tool of claim 38 wherein the flank surface of the substrate has a surface roughness that is less than the surface roughness of the rake surface and which is less than 25 microinches R_a.

44. The coated cutting tool of claim 43 wherein the coated rake face has a surface roughness of between 15 microinches R_a and 125 microinches R_a, and the coated flank face has a surface roughness that is less than the surface roughness of the coated rake face and is less than 25 microinches R_a.

45. The coated cutting tool of claim 43 wherein the coated rake face has a surface roughness of less than 25 microinches R_a, and the coated flank face has a surface roughness of less than 25 microinches R_a.

46. The coated cutting tool of claim 38 wherein the composition of the substrate comprises:

between 0.2 and 2.9 weight percent Co; and

the balance consisting essentially of tungsten carbide.

47. The coated cutting tool of claim 38 wherein the roughened rake surface is achieved by resintering the as-sintered substrate.

48. The coated cutting tool of claim 47 wherein the resintering occurs in a nitrogen atmosphere.

49. The coated cutting tool of claim 38 wherein the substrate is a ceramic.

50. The coated cutting tool of claim 38 wherein the substrate is a reinforced ceramic.

51. The coated cutting tool of claim 38 wherein the substrate is a cermet.

52. The coated cutting tool of claim 38 wherein the substrate is polycrystalline diamond.

53. The coated cutting tool of claim 38 wherein the substrate is polycrystalline cubic Boron Nitride.

54. The coated cutting tool of claim 38 wherein the substrate comprises a hard carbide and a binder metal, and the substrate having a binder-enriched peripheral layer.

55. The coated cutting tool of claim 54 wherein the PVD coating has an adherence as measured by the Rockwell A indentation adhesion load test of greater than or equal to 60 kg.

56. The coated cutting tool of claim 55 further including at least one layer between the PVD layer and the substrate applied by chemical vapor deposition.

57. An uncoated cutting tool comprising:

a polycrystalline diamond substrate having a rake face, a flank face and a cutting edge formed at a juncture of the rake face and flank face; and

wherein said rake face has a roughened surface.

58. The uncoated cutting tool according to claim 57 wherein said roughened surface is formed by laser etching.

59. The uncoated cutting tool according to claim 57 whereby said roughened surface provides acceptable chip control when said cutting tool is used in a chip forming machining operation.

60. The uncoated cutting tool according to claim 57 wherein said roughened surface has a surface roughness of between 15 microinches Ra and 125 microinches Ra.

61. The uncoated cutting tool according to claim 57 wherein said roughened surface has a surface roughness of between 25 microinches Ra and 125 microinches Ra.

62. The uncoated cutting tool according to claim 57 wherein said roughened surface has a surface roughness of between 40 microinches Ra and 80 microinches Ra.