Influence of tool cooling on thrust forces in tapping operations of reinforced polyamide

The machining with compressed air cooling has been identified as an environmentally conscious process. Its good performance has been achieved in materials as titanium alloys or aluminum alloys, but composites have not been explored. This work presents a first study related to evolution of thrust forces during the tapping process in reinforced polyamide with glass fiber, in particular PA66-GF30, when the tool cooling is considered. The experimental methodology was carried out by tapping operations in plates of PA66-GF30, using a drilling center. The experimental tests were executed using compressed air cooling by means of a vortex-tube cooling, in dry. Taps are of high-speed-steel with cobalt as base material and with coating; their geometry and dimensions are M12x1.75 mm. Outcomes obtained confirm that the methodology is appropriate in the tapping process of PA66-GF30. The tool cooling provides a reduction of thrust forces, although it is conditioned by type of tap and the coating.