A Microprocessor Controlled Twist Drill Grinder for Automated Drill Production

Abstract

The presently available twist drill grinding machines evolved over a long period of time. They are a product of engineering ingenuity through trial and error. A recently developed mathematical model of twist drill geometry has made it possible to design rationally and to construct a geometrically simple drill grinding machine which provides for the separate and precise specification and adjustment of the important geometry parameters. The machine grinds a conical drill point specified by the four parameters of the model. The conical drill point model can be used to approximate the geometry of hyperboloidal and ellipsoidal drills, and these drills may also be ground on this machine. A microprocessor is used to control the drill grinder. It does the calculations required to convert the drill specifications into the proper positions and movements. It then controls the motion of the machine axes to initiate and complete the grinding process. The result is a machine that is simple mechanically and able to produce a variety of drill points to predetermined specifications.