Cutting insert, tool holder, and related method

1. A generally parallelogram-shaped cutting insert, comprising:

a top face;

first and second main radial clearance faces, each intersecting the top face;

first and second minor axial clearance faces, each intersecting the top face and connecting the first and second main radial clearance faces;

a main cutting edge at the intersection of the top face and the first main radial clearance face; and

a variable radial rake angle along the length of the main cutting edge, the main cutting edge comprising a portion having a positive radial rake angle and a portion having a negative radial rake angle;

wherein the first main radial clearance face and the second main radial clearance face each comprise at least two radial clearance surfaces; and

the first minor axial clearance face and the second minor axial clearance face each comprise at least two axial clearance surfaces.

2. The generally parallelogram-shaped cutting insert of claim 1 , wherein the radial rake angle of the main cutting edge changes from a positive radial rake angle to a negative radial rake angle along the main cutting edge.

3. The generally parallelogram-shaped cutting insert of claim 1 , further comprising:

a main corner nose.

4. The generally parallelogram-shaped cutting insert of claim 1 , wherein the radial rake angle of the main cutting edge near the main corner nose is positive.

5. The generally parallelogram-shaped cutting insert of claim 4 , wherein the radial rake angle is zero at least at one point along the main cutting edge.

6. The generally parallelogram-shaped cutting insert of claim 5 , wherein the radial rake angle is zero at only one point along the main cutting edge.

7. The generally parallelogram-shaped cutting insert of claim 1 , wherein the length of the portion of the main cutting edge having a positive radial rake angle is at least three times longer than the length of the portion of the main cutting edge having a negative radial rake angle.

8. The generally parallelogram-shaped cutting insert of claim 1 , further comprising:

a cutting edge at the intersection of the top face and the first main radial clearance face; and

a cutting edge at the intersection of the top face and the second main radial clearance face;

wherein each cutting edge includes a variable radial rake angle along the length of the cutting edge, the main cutting edge comprising a portion having a positive radial rake angle and a portion having a negative radial rake angle.

9. The generally parallelogram-shaped cutting insert of claim 8 , further comprising:

a bottom face; and

two minor cutting edges, each minor cutting edge comprising at least a first portion and a second portion, wherein the first portion comprises a facet edge parallel to the bottom face and the second portion at an angle to the facet edge of the first portion.

10. The generally parallelogram-shaped cutting insert of claim 1 , further comprising:

two main corner noses and two minor corner noses, each major corner nose and each minor corner nose connecting a main cutting edge and a minor cutting edge, and wherein each of the main corner noses is one of a full nose and a truncated nose.

11. The generally parallelogram-shaped cutting insert of claim 1 , wherein at least one radial clearance face includes a notch.

12. The generally parallelogram-shaped cutting insert of claim 1 , wherein at least one radial clearance face includes a notch extending across the entire radial clearance face.

13. The generally parallelogram-shaped cutting insert of claim 1 , wherein at least one axial clearance face includes a notch.

14. The generally parallelogram-shaped cutting insert of claim 13 , wherein at least one axial clearance face includes a notch extending across at least a portion of the axial clearance face.

15. A peripheral cutting tool, comprising:

a tool holder comprising at least one insert pocket; and

a generally parallelogram-shaped cutting insert comprising a main cutting edge, wherein the cutting insert is positioned in the insert pocket of the tool holder such that a midpoint of the main cutting edge is located in a primary radial plane comprising the axis of rotation of the tool holder, and wherein a support plane including a bottom surface of the insert pocket is perpendicular to a secondary radial plane that comprises the axis of rotation of the tool holder and is perpendicular to the primary radial plane;

wherein the generally parallelogram-shaped cutting insert comprises:

a top face;

first and second main radial clearance faces, each intersecting the top face;

first and second minor axial clearance faces, each intersecting the top face and connecting the first and second main radial clearance faces;

a main cutting edge at the intersection of the top face and the first main radial clearance face; and

a variable radial rake angle along the length of the main cutting edge, the main cutting edge comprising a portion having a positive radial rake angle and a portion having a negative radial rake angle.

16. The peripheral cutting tool of claim 15 , wherein the radial rake angle of the main cutting edge changes from a positive radial rake angle to a negative radial rake angle along the main cutting edge.

17. The peripheral cutting tool of claim 16 , wherein the length of the portion of the main cutting edge having a positive radial rake angle is at least three times longer than the length of the portion of the main cutting edge having a negative radial rake angle.

18. The peripheral cutting tool of claim 15 , wherein the generally parallelogram-shaped cutting insert comprises a main corner nose.

19. The peripheral cutting tool of claim 15 , wherein the radial rake angle of the main cutting edge near the main corner nose is positive.

20. The peripheral cutting tool of claim 15 , wherein the parallelogram-shaped cutting insert comprises:

a cutting edge at the intersection of the top face and the first main radial clearance face; and

a cutting edge at the intersection of the top face and the second main radial clearance faces;

wherein each such cutting edge has a variable radial rake angle along the length of the cutting edge, each such cutting edge comprising a portion having a positive radial rake angle and a portion having a negative radial rake angle.

21. A method for positioning a generally parallelogram-shaped cutting insert comprising a main cutting edge in an insert pocket of a tool holder of peripheral cutting tool, the method comprising:

positioning the cutting insert in the insert pocket so that a midpoint of the main cutting edge is located in a primary radial plane comprising the axis of rotation of the tool holder, and wherein a support plane including a bottom surface of the insert pocket is perpendicular to a secondary radial plane that comprises the axis of rotation of the tool holder and is perpendicular to the primary radial plane;

wherein the generally parallelogram-shaped cutting insert comprises:

a top face;

first and second main radial clearance faces, each intersecting the top face;

first and second minor axial clearance faces, each intersecting the top face and connecting the first and second main radial clearance faces;

a main cutting edge at the intersection of the top face and the first main radial clearance face; and

a variable radial rake angle along the length of the main cutting edge, the main cutting edge comprising a portion having a positive radial rake angle and a portion having a negative radial rake angle.

22. The method of claim 21 , wherein the radial rake angle of the main cutting edge changes from a positive radial rake angle to a negative radial rake angle along the main cutting edge.

23. The method of claim 21 , wherein the generally parallelogram-shaped cutting insert comprises a main corner nose.

24. The method of claim 21 , wherein the radial rake angle of the main cutting edge near the main corner nose is positive.

25. The method claim 21 , wherein the length of the portion of the main cutting edge having a positive radial rake angle is at least three times longer than the length of the portion of the main cutting edge having a negative radial rake angle.

26. A generally parallelogram-shaped cutting insert, comprising:

a top face;

a bottom face;

first and second main radial clearance faces, each intersecting the top face;

first and second minor axial clearance faces, each intersecting the top face and connecting the first and second main radial clearance faces;

a main cutting edge at the intersection of the top face and the first main radial clearance face;

a variable radial rake angle along the length of the main cutting edge, the main cutting edge comprising a portion having a positive radial rake angle and a portion having a negative radial rake angle;

a cutting edge at the intersection of the top face and the first main radial clearance face;

a cutting edge at the intersection of the top face and the second main radial clearance face;

wherein each cutting edge includes a variable radial rake angle along the length of the cutting edge, the main cutting edge comprising a portion having a positive, radial rake angle and a portion having a negative radial rake angle; and

two minor cutting edges, each minor cutting edge comprising at least a first portion and a second portion, wherein the first portion comprises a facet edge parallel to the bottom face and the second portion at an angle to the facet edge of the first portion.

27. The generally parallelogram-shaped cutting insert of claim 26 , wherein the radial rake angle of the main cutting edge changes from a positive radial rake angle to a negative radial rake angle along the main cutting edge.

28. The generally parallelogram-shaped cutting insert of claim 26 , further comprising:

a main corner nose.

29. The generally parallelogram-shaped cutting insert of claim 26 , wherein the radial rake angle of the main cutting edge near the main corner nose is positive.

30. The generally parallelogram-shaped cutting insert of claim 29 , wherein the radial rake angle is zero at least at one point along the main cutting edge.

31. The generally parallelogram-shaped cutting insert of claim 30 , wherein the radial rake angle is zero at only one point along the main cutting edge.

32. The generally parallelogram-shaped cutting insert of claim 26 , wherein the length of the portion of the main cutting edge having a positive radial rake angle is at least three times longer than the length of the portion of the main cutting edge having a negative radial rake angle.

33. The generally parallelogram-shaped cutting insert of claim 26 , further comprising:

two main corner noses and two minor corner noses, each major corner nose and each minor corner nose connecting a main cutting edge and a minor cutting edge, and wherein each of the main corner noses is one of a full nose and a truncated nose.

34. The generally parallelogram-shaped cutting insert of claim 26 , wherein

the first main radial clearance face and the second main radial clearance face each comprise at least two radial clearance surfaces; and

the first minor axial clearance face and the second minor axial clearance face each comprise at least two axial clearance surfaces.

35. The generally parallelogram-shaped cutting insert of claim 26 , wherein at least one radial clearance face includes a notch.

36. The generally parallelogram-shaped cutting insert of claim 26 , wherein at least one radial clearance face includes a notch extending across the entire radial clearance face.

37. The generally parallelogram-shaped cutting insert of claim 26 , wherein at least one axial clearance face includes a notch.

38. The generally parallelogram-shaped cutting insert of claim 37 , wherein at least one axial clearance face includes a notch extending across at least a portion of the axial clearance face.