An exploration of friction models for the chip–tool interface using an Arbitrary Lagrangian–Eulerian finite element model

A better understanding of friction modeling is required in order to produce more realistic finite element models of machining processes to support the goals of longer tool life and better surface quality. In this work an attempt has been made to explore and evaluate various friction models used in numerical metal cutting simulations. A finite element model, based on the ALE approach, was developed for orthogonal machining and used to study the conditions prevailing at the chip–tool interface for hardened steel. The ALE approach does not require any chip separation criteria and enables an approximate initial chip shape to smoothly evolve into a reasonable chip shape, while maintaining excellent mesh properties. The results, for a wide range of feed values, were obtained using different friction models and are compared to previously published experimental findings. A reasonable agreement was obtained between the measured and predicted forces with some discrepancy between the cutting and feed force depending on the friction model: if agreement with the cutting forces was good, then the feed force was underestimated; if the feed force agreed well, then the cutting force was overestimated. In all cases the chip thickness was well estimated but the chip–tool contact length was underestimated.