Detection of tooth breakage in end milling using machine tool axis control signals

Abstract

This paper considers the feasibility of utilizing existing machine tool axis drive control signals as a mechanism for the early identification of tool breakages. In particular the paper outlines the utilization of axis tachometer feedback signals as a means of monitoring the cutting process of a computer numerical control vertical milling machine. The work describes how a fault signature, corresponding to a tool breakage, can be identified in the axis tachometer signals at varying feed rates. The results of the preliminary testing of a monitoring system utilizing existing axis feed drive signals are presented. The paper then outlines steps being taken to develop the application of the method to an increased range of cutting conditions. This work was based upon a study of the interrelationship between the axis control signals when cutting is proceeding in either the X - or the Y -axis direction, and when both the X axis and the Y axis are feeding simultaneously.