| CPC B23C 5/109 (2013.01) [B23C 5/20 (2013.01); B23C 5/202 (2013.01)] | 20 Claims |
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1. A cutting insert, comprising:
a base comprising
a first surface having a polygonal shape,
a second surface located on a side opposite to the first surface, and
a lateral surface located between the first surface and the second surface, wherein
the first surface comprises
a first corner,
a second corner located adjacent to the first corner, and
a first side located between the first corner and the second corner,
the lateral surface comprises a first lateral surface which is located from the first side to the second surface and comprises a first rake surface region,
the first side, in a front view of the first surface, comprises
a first portion having a straight line shape and extended from the first corner toward the second corner,
a second portion having a straight line shape and located closer to the second corner than the first portion,
a third portion having a straight line shape and located closer to the second corner than the second portion, and
a fourth portion having a straight line shape and extended from the second corner toward the first corner,
in the front view of the first surface,
an imaginary straight line being in contact with and extending along the first portion is a reference line,
each of the second portion and the fourth portion is inclined relative to the reference line so as to extend away from the reference line in a direction extending away from the first portion,
an inclination angle of the first portion relative to the reference line is a first angle, an inclination angle of the second portion relative to the reference line is a second angle, an inclination angle of the third portion relative to the reference line is a third angle, and an inclination angle of the fourth portion relative to the reference line is a fourth angle,
the third angle is smaller than each of the second angle and the fourth angle, and
the fourth angle is larger than the second angle.
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