Investigations on the effects of different tool edge geometries in the finite element simulation of machining

Abstract

This work focuses on the effects of cutting edge geometries on dead metal zone formation, as well as stress and temperature distributions in orthogonal cutting of P20 material using finite element method (FEM) simulation with sharp, chamfered, double chamfered and blunt tools. The cutting process is simulated with Arbitrary Lagrangian-Eulerian (ALE) approach in ABAQUS/Explicit. The simulation results suggest that the tool edge geometry influences the shape of dead metal zone considerably, while having little influence on the chip formation. An analysis of thermo-mechanical coupling was also conducted, and the results show that the stress distribution is affected by the temperature distribution and cutting speed because of the thermal softening effect and the strain rate hardening. A common analytical model is introduced to predict the residual stress, and equivalent Mises residual stresses are all calculated with four different tools to suggest that the tool edge geometry has a significant effect on the residual stress. The experiments are conducted using a CNC with former four kinds of tools at a speed of 480 m/min, and the residual stresses beneath the machined surface were measured with X-ray diffraction and electro-polishing techniques, and a chamfer tool at three different cutting speeds (250, 600 and 1000 m/min) to obtain the forces. The machining forces in both the cutting and thrust directions increases as the chamfer angle increases and decreases as the cutting speed increases.