Thin film sensor for wear detection of cutting tools

This contribution deals with novel smart tools for the cutting industry. Based on the combination of advanced coating techniques with an efficient sensor and MEMS technology smart tools have been realized, which enable on-line control of the cutting conditions measured directly at the cutting edges. For achieving this, special thin film sensors for wear measurement have been integrated into the hard coating system of cutting inserts. Since the sensors are arranged at the vertical flank of inserts, the electrical wiring must run over the edges to a shadowed flank area, where only one electrical contact was placed. This contacted an electronic module, which contained signal conditioning and telemetric transfer of the data to the control station of the lathe. The other pole of the sensors was connected to ground. This paper focussed on a novel sensor technique, which makes use of a wear resistant hard layer system and a microstructuring technique for the lithographic fabrication of the sensor and wiring structures. The inserts with integrated surface sensors showed a good performance during turning operations with different types of steel. (C) 2004 Elsevier B.V. All rights reserved.