Cutting insert and cutting tool

Patent metadata

Field	Value
Publication number	US-8992134-B2
Application number	US-201313758885-A
Country	US
Kind code	B2
Filing date	Feb 4, 2013
Priority date	Jul 4, 2011
Publication date	Mar 31, 2015
Grant date	Mar 31, 2015

Abstract

An upper surface of a cutting insert includes a first rake face and a second seating surface. A lower surface of the cutting insert includes a second rake face and a first seating surface. The cutting edge includes a first cutting edge portion formed at a crossing edge line portion between the first rake face and a flank face and a second cutting edge portion formed at a crossing edge line portion between the second rake face and the flank face. The first cutting edge portion and the crossing edge line portion between the first seating surface and the flank face are positioned opposite each other. The second cutting edge portion and the crossing edge line portion between the second seating surface and the flank face are positioned opposite each other.

First claim

What is claimed is:

1. A cutting insert formed like a plate and comprising a seating surface and a cutting edge formed thereon, the seating surface formed like a plate and serving as an abutting surface when the cutting insert is attached to a tool main body, the cutting edge being formed at a crossing edge line portion between a rake face and a flank face provided on a side surface of the plate,
wherein the plate includes an upper surface with a first rake face and a second seating surface formed thereon and a lower surface with a second rake face and a first seating surface formed thereon,
the cutting edge comprises a substantially circular-arc-shaped first cutting edge portion formed at a crossing edge line portion between the first rake face formed on the upper surface of the plate and a first flank face portion formed on the side surface of the plate, and a substantially circular-arc-shaped second cutting edge portion formed at a crossing edge line portion between the second rake face formed on the lower surface of the plate and a second flank face portion formed on the side surface of the plate,
between the upper surface and lower surface of the plate, the substantially circular-arc-shaped first cutting edge portion and a crossing edge line portion between the first seating surface and the first flank face portion are positioned opposite each other, and
between the upper surface and lower surface of the plate, the substantially circular-arc-shaped second cutting edge portion and a crossing edge line portion between the second seating surface and the second flank face portion are positioned opposite each other.

2. The cutting insert according to claim 1 , wherein the substantially circular-arc-shaped first cutting edge portion and the substantially circular-arc-shaped second cutting edge portion have different lengths.

3. The cutting insert according to claim 1 , wherein the cutting insert has a substantial crescent shape, and two vertices of the substantial crescent shape each form an acute angle.

4. The cutting insert according to claim 1 , comprising at least two attaching holes penetrating the upper and lower surfaces of the plate.

5. The cutting insert according to claim 1 , wherein:
a virtual central plane (P 1 ) passing midway between the upper surface and the lower surface is referred to as a first virtual plane, and
the first flank face portion is orthogonal to the first virtual plane, and
the second flank face portion crosses the first virtual plane at an acute angle or an obtuse angle.

6. A rotary cutting tool on which at least one cutting insert according to claim 1 is removably installed.

7. The rotary cutting tool according to claim 6 , comprising a screw hole for fixing a press bolt to retain the at least one cutting insert.

8. The rotary cutting tool according to claim 6 , wherein the rotary cutting tool is a ball end mill.

9. The rotary cutting tool according to claim 8 , wherein:
two attaching holes penetrate the upper and lower surfaces of the plate; and
the first flank face portion is parallel to a central axis of at least one of the attaching holes penetrating the upper and lower surfaces of the plate.

10. The rotary cutting tool according to claim 8 , wherein:
two cutting inserts are removably installed in the ball end mill;
on each of the two cutting inserts, the substantially circular-arc-shaped first cutting edge portion and the substantially circular-arc-shaped second cutting edge portion have different lengths
a first of the two cutting inserts is mounted such that the substantially circular-arc-shaped first cutting edge portion is operative; and
a second of the two cutting inserts is mounted such that the substantially circular-arc-shaped second cutting edge portion is operative.

11. A plate-like cutting insert comprising:
an upper surface and a lower surface facing in opposite directions;
a side surface connecting the upper and lower surfaces, the side surface comprising a flank face and an abutting surface; wherein:
the upper surface has first rake face and a second seating surface formed thereon;
the lower surface has with a second rake face and a first seating surface formed thereon,
a substantially circular-arc-shaped first cutting edge portion is formed at a crossing edge line portion between the first rake face formed on the upper surface and a first flank face portion formed on the side surface;
a substantially circular-arc-shaped second cutting edge portion is formed at a crossing edge line portion between the second rake face formed on the lower surface and a second flank face portion formed on the side surface;
between the upper surface and lower surface of the plate, the first cutting edge portion and a crossing edge line portion between the first seating surface and the first flank face portion are positioned opposite each other, and
between the upper surface and lower surface of the plate, the second cutting edge portion and a crossing edge line portion between the second seating surface and the second flank face portion are positioned opposite each other.

12. The plate-like cutting insert according to claim 11 , wherein the cutting insert has a substantial crescent shape, and two vertices of the substantial crescent shape each form an acute angle.

13. The plate-like cutting insert according to claim 11 , wherein the substantially circular-arc-shaped first cutting edge portion and the substantially circular-arc-shaped second cutting edge portion have different lengths.

14. The plate-like cutting insert according to claim 11 , comprising at least two attaching holes penetrating the upper and lower surfaces.

15. The plate-like cutting insert according to claim 11 , wherein:
a virtual central plane (P 1 ) passing midway between the upper surface and the lower surface is referred to as a first virtual plane, and
the first flank face portion is orthogonal to the first virtual plane, and
the second flank face portion crosses the first virtual plane at an acute angle or an obtuse angle.

16. The plate-like cutting insert according to claim 11 , wherein:
the abutting surface of the cutting insert's side surface is provided with an orienting cutout configured to prevent improper seating of the cutting insert.

17. A ball endmill comprising two plate-like cutting inserts in accordance with claim 11 removably installed therein, wherein:
on each of the two plate-like cutting inserts, the substantially circular-arc-shaped first cutting edge portion and the substantially circular-arc-shaped second cutting edge portion have different lengths
a first of the two plate-like cutting inserts is mounted such that the substantially circular-arc-shaped first cutting edge portion is operative; and
a second of the two plate-like cutting inserts is mounted such that the substantially circular-arc-shaped second cutting edge portion is operative.

18. The ball endmill according to claim 17 , wherein:
the abutting surface of each cutting insert's side surface is provided with an orienting cutout configured to prevent improper seating of the cutting insert;
the ball endmill comprises orienting projections corresponding to the orienting cutouts formed on the cutting inserts' abutting side surfaces.

19. The ball endmill according to claim 17 , comprising a screw hole for each cutting insert for fixing a press bolt to retain said each cutting insert.

Assignees

• Tungaloy Corp

Inventors

• Bhagath Kedar Suresh

Classifications

• B23C5/205

  characterised by chip-breakers of special form · CPC title

• Y10T407/1934

  with separate means to fasten tool to holder · CPC title

• B23C5/1027 Primary

  with one or more removable cutting inserts · CPC title

• B23C2200/362

  Having two fixation holes · CPC title

• B23C2210/168

  Seats for cutting inserts, supports for replacable cutting bits · CPC title