Matrix diamond drag bit with PCD cylindrical cutters

摘要

A drag bit mold fabricated from high temperature resisting material is machined to accept cylindrically shaped polycrystalline diamond cutters (PCD) having tungsten carbide bodies. Each of the multiple PCD matrix pockets in the mold is formed by two independent non-parallel end mill passes. The first end mill cut defines the PCD cutter position in the cutting face of the matrix diamond drag bit. The second end mill cut superimposed over the first end mill pocket creates a surrounding pocket which fills with powder metallurgy matrix material to provide support for the cylindrical cutter. The second end mill is only slightly larger than the first end mill to minimize the size of the insert securing fillet subsequently formed thus assuring that the fillet will not interfere with the depth of penetration of each of the PCD cutters.