Abstract
Tool damage detecting system has been developed by using a wear sensor-integrated cutting insert and an eddy current type proximity switch. A beltlike TiN coated layer on cutting edges was used as the sensor. The TiN layer has good electric conductivity, so that when the layer is damaged, an electric resistance of the layer becomes large or infinity. To detect the conductivity of the sensor without wire, a resonance circuit consisted with the sensor, a coil and a capacitor was used. The coil of the resonance circuit acts as a metal to the eddy current type proximity switch when the sensor has low resistance, while the sensor becomes high resistance, an electric current becomes small and the coil can not act as a metal anymore, so that the switch can detect the breakage of the tool.
