Analytical and numerical solutions of transient heat conduction in monolayer-coated tools

Abstract

The heat generation during metal cutting processes affects accuracy of the machined surface and strongly influences tool wear and tool life. Knowledge of the ways in which the tool material affects the temperature distribution is therefore essential for the study of thermal effects on tool life and workpiece quality. Many studies have been done on simulation temperature distribution in coated cutting tools by means of the finite element method or the finite difference method. In this study, a thermal analytical model is firstly developed to determine temperature distribution in monolayer-coated cutting tools during orthogonal metal cutting. In the analytical model one equivalent heat source applied on the coating layer boundary substitutes for the heat generation introduced from the primary deformation zone, the secondary deformation and the frictional zone along the tool–chip interface as well as the tertiary or the sliding frictional zone at tool–workpiece interface. A mathematical model of the transient heat conduction in monolayer-coated tools is then proposed. The temperature distribution formulations in monolayer-coated tools are obtained using Laplace transform. The influence of different parameters including thermophysical properties of tool coating and tool substrate and thickness of the coating layer on temperature distribution in monolayer-coated tools is lastly discussed and illustrated.