Cutting insert and insert cutter.

摘要

A cutting insert is disclosed which includes a polygonal plate-like insert body (21) having two opposite faces (22) directed in the direction of insert thickness and a plurality of peripheral faces (23) lying between the opposite faces. The opposite faces (22) have marginal ridges with at least one of the marginal ridges defining a main cutting edge (24). The peripheral faces (23) intersect one another to form marginal ridges (25), with one of the marginal ridges defining an auxiliary cutting edge (27) which intersects the main cutting edge (24). The peripheral surface (23) which includes the marginal ridges (25) defining the main (24) and auxiliary (27) cutting edges includes a rake surface (28) extending along the main (24) and auxiliary (27) cutting edge. This rake surface (28) is formed into a step-like formation of a plurality of sections disposed adjacent to one another to define marginal ridges terminating at one end at the main cutting edge (24) and to be convexly shaped in such a manner that an angle defined between a respective section and one of the opposite faces which extends from the main cutting edge (24) decreases stepwise in a direction away from the nose portion (29). At least one of the marginal ridges of the sections has the other end extending to the marginal ridge defined between the peripheral faces (23). Moreover, an insert cutter which employs the aforesaid insert is also disclosed.