Cutting tool and insert therefor

• US 5,741,095 A
• Filed: 01/13/1997
• Issued: 04/21/1998
• Est. Priority Date: 03/12/1993
• Status: Expired due to Term

• Current Assignee: Valenite LLC (Sandvik AB)
• Original Assignee: Valenite Inc.
• Inventors: Reiterman, Lee, Charron, Mike, Powell, Foye
• Primary Examiner(s): Lavinder, Jack W.
• Application Number:
  US08/790,483
• Time in Patent Office: 463 Days
• Field of Search: 407/42, 407/48, 407/53, 407/54, 407/55, 407/62, 407/113
• US Class Current: 407/42
• CPC Class Codes: B23C 2200/083 curved
• CPC Class Codes: B23C 2200/085 discontinuous
• CPC Class Codes: B23C 2200/088 spherical
• CPC Class Codes: B23C 2200/203 Curved cutting edges
• CPC Class Codes: B23C 5/1027 with one or more removable cutting inserts
• CPC Class Codes: B23C 5/2213 having a special shape
• CPC Class Codes: Y10T 407/1924 Specified tool shape
• CPC Class Codes: Y10T 407/1936 Apertured tool
• CPC Class Codes: Y10T 407/1946 Face or end mill
• CPC Class Codes: Y10T 407/1964 Arcuate cutting edge
• CPC Class Codes: Y10T 407/23 including tool having plural alternatively usable cutting edges

Abstract

A ball end mill and an insert for use in the cutting tool. The insert has a constant angle maintained along the entire clearance face.

Claims

1. A cutting tool comprising:

a cylindrical shank terminating in a spherical cutting end and including at least one mounting cavity shaped for receipt in lay-down fashion of an indexable cutting insert, and means mounting the indexable cutting insert to the mounting cavity, the indexable cutting insert comprising first and second polygonal major faces and flank surfaces forming the sides of a polygon, said second major face being planar and intersecting each flank forming an included angle of at least 90 degrees, the first major face including upwardly sloping convex portions, each convex portion intersecting a flank face to form an arcuate cutting edge along a side of the polygon, said convex portions including clearance face portions extending along said first major face rearwardly from said cutting edges, the slope of said clearance faces defining a clearance angle measured relative to a line drawn over the first major face parallel to the second major face and through the center of the insert normal to the second major face, said clearance angle being constant as measured around the entire perimeter of the insert, the cavity oriented such that an arcuate cutting edge of said insert placed in lay-down fashion in the cavity will extend radially outwardly from a longitudinal axis of the shank.

2. The cutting tool of claim 1, wherein all said arcuate cutting edges are identical.

3. The cutting tool of claim 1, further comprising at least one chip gullet respectively intersecting the mounting cavity such that chips formed by the arcuate cutting edges are directed by the planar flank surfaces into the chip gullet.

4. The cutting tool of claim 1, wherein said clearance angle is constant at an angle of between about 5 to 25 degrees.

5. The cutting tool of claim 4, wherein said clearance angle is constant at an angle of about 18 degrees.

6. The cutting tool of claim 1, wherein said first and second polygonal major faces are equilateral and have identical flank surfaces.

7. The cutting tool of claim 1, wherein each said flank is planar.

8. The cutting tool of claim 1, wherein the angle formed by the intersection of the second major face and the flank is obtuse.

9. The cutting tool of claim 1 further including a second mounting cavity, said second cavity positioned on the cutting end with respect to the first cavity such that a second insert placed in lay down fashion therein presents an active arcuate cutting edge having a cutting zone which partially overlaps the cutting zone of the first insert and such that an arcuate cut of substantially uniform radius is generated by the first and second inserts.

10. The cutting tool of claim 1 wherein the second major face rests upon a planar mounting floor of the mounting cavity.

11. The cutting tool of claim 10, wherein each planar mounting floor is intersected by a threaded cavity in the spherical cutting end for receipt of an insert mounting screw.

12. The cutting tool of claim 11 wherein said first and second major faces are minimally spaced at corners of the polygon.

13. An indexable cutting insert comprising:

first and second polygonal major faces and flank surfaces forming the sides of a polygon, said second major face being planar and intersecting each flank surface forming an included angle of at least 90 degrees, the first major face including upwardly sloping convex portions, each convex portion intersecting a flank surface to form an arcuate cutting edge along a side of the polygon, said convex portions including corresponding clearance face portions extending along said first major face rearwardly from said cutting edges, the slope of said clearance faces defining a clearance angle relative to a line drawn over the first major face parallel to the second major face and through the center of the insert normal to the second major face, said clearance angle being constant as measured around the entire perimeter of the insert.

14. The insert of claim 13, wherein said clearance angle is from about 5 to 25 degrees.

15. The insert of claim 14, wherein said clearance angle is about 18 degrees.

16. The insert of claim 13, wherein said first and second polygonal major faces are equilateral and have identical flank surfaces.

17. The insert of claim 13, wherein said flank surfaces are planar.

18. The insert of claim 13, wherein said arcuate cutting edges are identical.

19. The insert of claim 13, further including a centrally located aperture extending through the insert and normal to the first and second major faces.

20. The insert of claim 13, wherein the angle formed by the intersection of the second major face and the flank is obtuse.