CUTTING INSERT

摘要

In a cutting insert, a base plate is formed into a polygonal configuration having a plurality of corners. At least one cutting-edge element is mounted on an upper surface of the corner of the base plate. The cutting-edge element is composed of a high-hardness sintered section and a super-hard sintered section which are superimposed one upon the other. The cutting-edge element is brased to the upper surface of the corner of the base plate under such a condition that the super-hard sintered section is exposed to an upper surface of the base plate. The super-hard sintered section has its upper surface which is formed therein with a chip breaker having a surface roughness within a range of from 0.5S to 10S. Furthermore, in a polygonal cutting insert having a plurality of corners which have formed therein respective chip breakers, at least one of the chip breakers is different in form from the remaining chip breakers.