TECHNICAL FIELD

The present disclosure relates to a cutting insert.

BACKGROUND ART

WO 2016/017470 (Patent Literature 1) describes a cutting insert having a corner cutting edge, a first rake face, a second rake face, and a raised portion. The second rake face is located between the corner cutting edge and the raised portion and is depressed relative to the first rake face.

CITATION LIST

Patent Literature

PTL 1: WO 2016/017470

SUMMARY OF INVENTION

A cutting insert according to the present disclosure includes a top surface, a seating surface, and an outer peripheral surface. The seating surface is located opposite to the top surface. The outer peripheral surface is continuous to each of the top surface and the seating surface. A ridgeline between the top surface and the outer peripheral surface constitutes a cutting edge. The cutting edge includes: a corner cutting edge portion having a curved shape; a first cutting edge portion having a straight shape and continuous to one end of the corner cutting edge portion; and a second cutting edge portion having a straight shape and continuous to the other end of the corner cutting edge portion. The top surface includes a first rake face, a second rake face, a third rake face, a front side surface, an upper surface, a first side surface, and a second side surface. The first rake face is continuous to the first cutting edge portion. The second rake face is continuous to the second cutting edge portion. The third rake face is continuous to the corner cutting edge portion and is continuous to each of the first rake face and the second rake face. The front side surface is located opposite to the corner cutting edge portion relative to the third rake face, and rises from the third rake face. The upper surface is located opposite to the third rake face relative to the front side surface, and is continuous to the front side surface. The first side surface is located opposite to the first cutting edge portion relative to the first rake face, and rises from the first rake face. The second side surface is located opposite to the first rake face relative to the first side surface, is inclined relative to the first side surface, and is continuous to each of the first side surface, the front side surface, and the upper surface. A ridgeline between the first side surface and the second side surface is continuous to the upper surface. When seen in a direction perpendicular to the seating surface, a width of a boundary between the front side surface and the third rake face is larger than a width of a boundary between the front side surface and the upper surface.

