| 摘要 |
<p>Provided is a cutting insert having a cutting edge portion formed to have a square cutting face. The cutting edge portion is equipped, at the end portion of a shaft-shaped insert body, with a pair of side cutting edges extending in the longitudinal direction of the insert body and a front cutting edge extending between the leading ends of those side cutting edges and in a direction to cross the longitudinal direction. At least one of paired corner edges, in which the side cutting edges and the front cutting edge intersect, as viewed in a direction perpendicular to the longitudinal direction and to confront the cutting face, is formed into a convex shape, in which tangents to the corner edges are turned from the front cutting edge along the corner edges in a direction extending the longitudinal direction and then merge into the side cutting edges with an inflection point to change the turning direction.</p> |
