Determination of work material flow stress and friction for FEA of machining using orthogonal cutting tests

Abstract

Finite element analysis based techniques are available to simulate cutting processes and offer several advantages including prediction of tool forces, distribution of stresses and temperatures, estimation of tool wear and residual stresses on machined surfaces, optimization of cutting tool geometry and cutting conditions. However, work material flow stress and friction characteristics at cutting regimes are not always available. This paper utilizes a metal cutting model developed by Oxley and presents an improved methodology to characterize work material flow stress and friction at primary and secondary deformation zones around the cutting edge by utilizing orthogonal cutting tests. In this paper, Johnson–Cook (JC) constitutive work flow stress model is used to characterize work flow stress in deformation zones. The friction model is based on estimation of the normal stress distribution over the rake face. The stress distribution over the tool rake face can either directly be entered in FEA software or used in determining a coefficient of the friction at the tool-chip interface. The methodology is practical and estimates the unknowns of both the work material constitutive model and the friction model over the rake face.