Patent ID: 8523497

Claim:
A single-sided cutting insert that is to be mounted detachably on a tool body ( 10 ) of an indexable face mill, comprising: a top face having a polygonal shape and a rake surface ( 2 ); a bottom face opposite the top face, the bottom face having a seat surface ( 3 ); main flank surfaces ( 4 a ) that are substantially flat surfaces having positive relief angles, provided on side faces extended from side ridges of the top face; pairs of sub-flank surfaces ( 4 b ) that are provided on side faces extended from vertex angle portions of the polygonal shaped faces; and vertex flank surfaces ( 4 c ) that are provided at the vertex angle portions between the pairs of sub-flank surfaces ( 4 b ), and are formed in a substantially projected outward curved shape, wherein the vertex flank surfaces ( 4 c ) are smoothly connected with the sub-flank surfaces ( 4 b ) in a tangential direction, and are extended along a thickness of the cutting insert in a direction along a vertex angle bisector line (B); wherein boundary lines ( 6 a ), formed by the vertex flank surfaces ( 4 c ) and the pairs of sub-flank surfaces ( 4 b ), are parallel to each other; and wherein as viewed from a direction opposite the rake surface ( 2 ), almost the same shape is provided for second curved ridges ( 5 c ), formed along an intersecting ridge line portion of the vertex flank surfaces ( 4 c ) and the rake surface ( 2 ), and for first curved ridges that are formed along an intersecting ridge line portion of the vertex flank surfaces ( 4 c ) at the vertex angle portion and the seat surface ( 3 ).