Simulation of orthogonal cutting: The effect of separation criteria and cutting tool geometry

A central step in understanding the mechanism of a material cutting process is the investigation of chip formation. Therefore, to build up a reliable finite element model for orthogonal cutting simulation, the chip formation phases must be analyzed first. In this study, the finite element analysis was applied to model and simulate the chip formation and the contact phenomena during the orthogonal cutting of metals. The material behavior during separation was modelled with a feasible constitutive equation that allows element death to occur upon rupture. The chip separation criteria were based on a critical accumulative effective plastic strain. A comparison with the relevant analytical solution of cutting forces was used to correlate the threshold of separation. Some special techniques were used to treat the contact and the generation of new contact surface during chip separation. The effects of local rake angle on cutting forces and residual stresses were addressed. The cutting forces and surface residual stresses were predicted with respect to cutting tool geometry. Results showed that under quasi-static steady plane-strain conditions, the chip separation threshold of 0.1 accumulative effective plastic strain yields close agreement with the analytical solution in terms of the cutting force stability and accuracy and that the local change of the tip rake angle plays a key role on not only the pattern of the distribution of surface residual stresses but also the stability of the cutting forces.