Cutting insert, cutting tool, and method of manufacturing machined product

Patent metadata

Field	Value
Publication number	US-2016288223-A1
Application number	US-201415037153-A
Country	US
Kind code	A1
Filing date	Nov 18, 2014
Priority date	Nov 20, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

A cutting insert according to an embodiment has a lower surface, an upper surface, a side surface disposed between the lower surface and the upper surface, a pair of corner cutting edges located along an intersection of the upper surface and the side surface, and a major cutting edge located between the pair of corner cutting edges. The major cutting edge has a downwardly dented curvilinear part and a pair of straight parts respectively extending from the curvilinear part toward the pair of corner cutting edges in a side view. A portion of the curvilinear part located lowermost is close to one corner cutting edge in the side view.

First claim

1 . A cutting insert, comprising:
a polygonal shaped upper surface comprising a pair of corner parts and a side part located between the pair of corner parts; a polygonal shaped lower surface corresponding to the upper surface; a side surface disposed between the lower surface and the upper surface; a pair of corner cutting edges located along an intersection of the pair of corner parts of the upper surface and the side surface; and a major cutting edge located along an intersection of the side part of the upper surface and the side surface, wherein the major cutting edge has a downwardly dented concave shape as a whole, and comprises
a first section having a downwardly dented concave curvilinear shape in a side view, and
a pair of second sections being in a shape of a straight-like line, the pair of second sections respectively extending from the first section toward the pair of corner cutting edges and having a larger height as approaching the pair of corner cutting edges, and
wherein a portion of the first section which is located lowermost is close to one of the corner cutting edges in the side view.

2 . The cutting insert according to claim 1 ,
wherein the pair of second sections comprises
a first straight part extending from the first section to one of the corner cutting edges, and
a second straight part extending from the first section to another of the corner cutting edges, and
wherein the first straight part is longer than the second straight part.

3 . The cutting insert according to claim 1 , wherein the side surface comprises a plane part located at a portion corresponding to the major cutting edge.

4 . The cutting insert according to claim 1 , wherein the major cutting edge has an inwardly dented concave shape in a top view.

5 . The cutting insert according to claim 1 ,
wherein the upper surface comprises
a first rake surface located along the first section of the major cutting edge,
a second rake surface located along the second section of the major cutting edge, and
a third rake surface located along the corner cutting edge, and
wherein a rake angle of the second rake surface is larger than a rake angle of each of the first rake surface and the third rake surface.

6 . The cutting insert according to claim 5 , wherein the rake angle of the first rake surface is larger than the rake angle of the third rake surface.

7 . The cutting insert according to claim 1 , wherein a bottom portion of the first section is close to one of the pair of corner cutting edges which is located away from a processing surface of a workpiece when cutting the workpiece.

8 . A cutting tool, comprising:
a holder comprising a plurality of insert pockets at a front end part of the holder, and a cutting insert according to claim 1 , the cutting insert being attached to the insert pocket so that the major cutting edge protrudes beyond the holder.

9 . A method of manufacturing a machined product, comprising:
rotating the cutting tool according to claim 8 ; bringing the major cutting edge in the cutting tool being rotated into contact with a workpiece; and separating the cutting tool from the workpiece.

Assignees

• Kyocera Corp

Inventors

• Ishi Hirohisa

Classifications

• B23C2200/208

  Wiper, i.e. an auxiliary cutting edge to improve surface finish · CPC title

• B23C2200/0455

  Square · CPC title

• B23C2200/0461

  rounded · CPC title

• B23C2200/203

  Curved cutting edges · CPC title

• B23C2200/205

  Discontinuous cutting edges · CPC title