Analyses of Drill Flute and Cutting Angles

Abstract

The analysis of drill cutting angles is important for the design of high-performance drill geometry. The cutting angles along the cutting edge of a drill are determined by the combination of its flute and flank surfaces. This paper examines the analysis of both flute and flank surface models and the evaluation of drill cutting angles. A new mathematical model for an arbitrary drill flute face is developed by sweeping the polynomial representation of the flute cross-sectional curve along the drill axis, with a helical movement. On the basis of the quadratic flank face, a relationship between the grinding and the geometrical design parameters of the flank face is also established. The vector analysis method is employed for the analysis of the cutting angles for various drill geometries. A comparison of the analytical results with the actual measured cutting angles of an example drill has shown that the average error is less than 5%.