Tool insert blanks and method of manufacture

摘要

A tool insert blank including first and second major surfaces and a plurality of edge surfaces defining an outer perimeter of the blank. A first layer defines the first major surface and a first portion of the plurality of edge surfaces proximate the first major surface. A second layer harder than the first layer is disposed substantially co-extensive with the second major surface and a second portion of the plurality of edge surfaces proximate the second major surface. At least one of the edge surfaces includes a projecting portion defining a first engagement plane and a recessed portion spaced inwardly of the engagement plane whereby the grinding wheel is engageable with the projecting portion without engaging the recessed portion. The second layer can be formed out of various materials including polycrystalline diamond and cubic boron nitride materials. A method of forming a tool insert blank is also disclosed.