Extracting cutting force coefficients from drilling experiments

Determining cutting force equations and the associated specific cutting pressures require a relatively large number of orthogonal cutting tests. These tests need to cover wide ranges of cutting speeds, feeds, and rake angles. Given the inherent variation of the rake angle and the tangential velocity over the drill's cutting lip, this work introduces a methodology for extracting these cutting force coefficients by performing a few drilling experiments on pre-drilled pilot holes.First, the contributions of the ploughing forces acting on the lip and margin are determined. Subtracting these edge forces from the measured total values, torque and thrust cutting forces and the corresponding cutting pressure distributions along the lip are derived. These distributions are then used to produce equations that estimate cutting force coefficients over a wide range of cutting parameters. The coefficients determined in this work from drilling experiments in Aluminium 6061-T6 compare favorably with others generated from orthogonal cutting experiments reported in the literature.