Abstract: A new approach for on-line monitoring of tool breakage in milling operations is pres-ented.It is based on recognizing changes in milling force/ torque wavefonn using a table dynamometer and a new kind of torque sensing cutter holder,which integrates a strain gauge and atransmitter.Two kinds of detecting algorithms to recognize milling tool breakage are proposed。 The first algorithm is the rate of peaks in tooth-period, and the other algorithm is the eccentricity relative to max. cutting thickness. They are independent of changes in the cutting conditions,so The threshold for alann can be easi ly set. The results of experiments confirm the practical applicability of the sensor and the detecting algorithms.

Key words: milling (machining), cutters, breaking, detection