Computer analysis of drill point geometry

Abstract

The difficulties in drill point geometry analysis are aggravated by the process of drill point design which now includes the hyperboloidal drill and ellipsoidal drill. This paper provides a tool based upon mathematical models for drill point and drill flute geometries which enables drill point geometry to be analyzed accurately and conveniently by computer. The explicit equations for the drill flank contour and the drill angles are derived and shown to be directly calculated from the grinding parameters. This methodology also enables one to calculate the shapes of cutting edges and chisel edges and their relationships with the grinding parameters. A flute contour is designed for the ellipsoidal drill to improve the excessive inclination angles of cutting edges near outside corners. The chisel edge shape is defined so that it can be measured quantitatively as well as qualitatively.