Effect of Cooling on the Torque of Tapping Processes in Polymer Composites

Abstract

The tapping process in polymer composites has been analysed; threaded holes have been formed in reinforced polyamide with glass fibre, PA66-GF30, with a tap of 15º as taper angle and titanium nitride, TiN, as coating. These tests have been carried out under different environmental temperatures by means of compressed cooling air through vortex tube. The cutting speeds reached values of 15, 37.5 and 60 m/min and environmental temperatures values of -18, 2 and 22 ºC. After an experimental data collection and a statistical analysis focussed on an analysis of variance and a response surface to create a second-order regression model, some interesting results are obtained. The lower torque can be found at temperatures close to 3 ºC and at high cutting speeds in the range studied, although the significant factor is the temperature; the cutting speed has a low influence. Therefore, the cooling has been an adequate procedure to reduce the torques.