On-Line Tool Wear Sensing for Turning Operations

Abstract

A sensing device was developed to measure tool wear indirectly by monitoring the change of the workpiece diameter during turning operations. The change in the diameter was sensed by electromagnetic sensors which gave a voltage output directly related to the gap between the sensor and the workpiece. After trying different alternatives, the final arrangement was set up with two sensors operating in a differential mode which allowed compensation for deflections and vibrations. The electromagnetic sensors could detect minute wear for the different cutting conditions used (speeds of 350–550 ft/min, feeds from from 0.0208–0.0232 in./rev. and depths of cuts from 0.030–0.100 in.). The experimental data obtained for flank and nose wear were in agreement with the results obtained from the conventional method of measuring the wear by a toolmaker’s microscope.