CPC B23B 27/1611 (2013.01) [B23B 35/00 (2013.01)] | 9 Claims |
1. A cutting insert, comprising:
an upper surface;
a lower surface located on a side opposite to the upper surface;
a front lateral surface located between the upper surface and the lower surface; and
a rear lateral surface located between the upper surface and the lower surface and located on a side opposite to the front lateral surface,
the upper surface comprising
a first upper cutting edge located on an intersection with the front lateral surface, and
an upper constraining surface which is located closer to the rear lateral surface than the first upper cutting edge, and which is contactable with a holder,
the lower surface comprising a lower constraining surface contactable with the holder,
the lower constraining surface comprising a lower protrusion extended from a side of the front lateral surface toward the rear lateral surface,
the lower protrusion comprising
a first region located on a side opposite to the upper constraining surface,
a second region located closer to the front lateral surface than the first region, and
a third region located closer to the rear lateral surface than the first region, wherein
a wedge angle of the first region is a first angle, a wedge angle of the second region is a second angle and a wedge angle of the third region is a third angle in a cross section orthogonal to an extending direction of the lower protrusion, and
the first angle is smaller than each of the second angle and the third angle.
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