Patent ID: 8251618

Claim:
A cutting insert comprising: an upper surface; a lower surface; a first side and a second side meeting at a corner section; an inner side defined between the first side, the second side and the corner section and extending in an inward direction from the corner section, the first side and the second side; a side surface intersecting with the upper surface and the lower surface; a cutting edge comprising a corner cutting edge located at the corner section and where the side surface intersects with the upper surface and comprising a first cutting edge located at the first side; a rake face extending along the cutting edge on the upper surface; and a protruding portion located deeper on the inner side than the rake face and located on the upper surface, the protruding portion comprising: a first surface inclined upward in the inward direction from the cutting edge; a second surface that is located on a higher location with respect to the first surface and deeper on the inner side with respect to the first surface and that is inclined upward in the inward direction; and a third surface located between the first surface and the second surface, wherein an intersection portion between the first surface and the third surface is inclined downward in the inward direction; wherein the rake face comprises: a first rake face extending along the cutting edge; and a second rake face located deeper on the inner side in relation to the first rake face and spaced from the corner section with respect to the first surface and the third surface, the second rake face being located between the first rake face and the second surface; wherein an intersection line along which the third surface meets the second rake face extends at an angle of 90 degree or less with respect to the first side as viewed in a top plane view from the upper surface in direction of the lower surface.