Patent ID: 9630256
Date: 2017-04-25
CPC Classifications: B23B,Y10T

Claim:
1. A cutting insert comprising: an insert main body which has a rake face and a flank face; and a cutting edge which is formed at a ridge section between the rake face and the flank face in the insert main body, the cutting edge provided with a corner section which forms a convex arc shape when seen in a planar view from the direction facing the rake face and a linear section which is in contact with the corner section at an end of the corner section and extends linearly, wherein the insert main body is formed symmetrical with respect to a bisector of the corner section when seen in the planar view, the cutting edge is provided with a first region along the corner section, a second region along the linear section, and a third region positioned between the first region and the second region along the linear section, when seen in the planar view, and a cross-sectional area of the insert main body orthogonal to the cutting edge is largest in the third region among the first, the second and the third regions, and is smallest in the second region among the first, the second and the third regions, the cross-sectional area of the insert main body being within a distance equal to a radius R (mm) of the corner section in perpendicular to the cutting edge in the planar view, and a border line between the second region and the third region in a planar view is positioned at where there is an increase in the cross-sectional area of the insert main body from the third region to the second region, an inclination face which is inclined toward a face on a side opposite to the rake face of the insert main body with moving toward the inside of the rake face from the cutting edge on a cross-section orthogonal to the cutting edge is formed on the rake face from the first region, the second region to the third region, and an inclination angle of the inclination face in the third region is smaller than an inclination angle of at least in one of the first region and the second region.