Tool Wear Monitoring Through the Dynamics of Stable Turning

Abstract

This paper describes a microcomputer-based technique for monitoring the flank wear on a single-point tool engaged in a turning operation. The technique is based on the real-time computation of a Wear Index (WI). This WI is a measure of the resistance, at the tool tip-workpiece interface along the flank, to the forced oscillations of the cantilever portion of the tool holder, during machining. Increasing flank wear results in an increasing area of contact between tool tip and workpiece. This translates to an increasing WI, proportional to flank wear-land width and independent of other cutting process variables. This WI, which can be computed on-line as a ratio of the measured dynamic force amplitude to the vibration amplitude, at the first natural frequency of the cantilever portion of the toolholder, forms the basis of the microcomputer system described in this paper for tool wear monitoring.