Worn Tool Forces Based on Ploughing Stresses

Recent work in modeling of the ploughing mechanism in basic metal machining may provide a means of estimating the additional forces to be expected when cutting with a worn tool. The results predict the rubbing stresses due to the finite radius of an unworn tool edge. Since an unworn tool can be thought of as a worn tool with a wear land width VB = 0, these stresses can make up part of a strategy for predicting the additional forces incurred by a worn tool. This paper develops a wear model by proposing a technique for utilizing the stresses predicted by the ploughing model to estimate the stresses on the flank based on both elastic contact and plastic flow at the flank. Orthogonal cutting experiments with worn tools were performed to test the approach. Predictions for these tests, as well as for previously published results, are presented and show great promise for achieving a reliable wear-force prediction strategy.