A no contact capacitive sensor to mechanical working control

Abstract The aim of this work is to use a capacitive sensor to obtain process control during turning. It will verify if the sensor is able to assess geometrical variation of the workpiece due to accidental tool failure or to regular tool wear. The sensor has no contact with the rotating piece. The experimental work consists in verifying if the capacity valued can be correlated to the real pass depth. The sensor was characterized by static tests measuring the capacity to the roughness variation of sample. The choice of dielectric was determined by the results obtained during the characterization, where it was seen that the best compromise between dimensions and sensibility of the sensor was obtained using a polyester dielectric 42 μm thick.