Cutting force, tool wear and surface finish in drilling metal matrix composites

In this paper the evolution of the cutting force, tool wear and surface fin ish, measured when drilling the metal matrix composite A356/20/SiCp-T6, is presented. The experimental work was developed through the continuous measu rement of the torque with an appropriate piezoelectric dynamometer and the results were used to derive the cutting power (ranging from 0.1 to 0.4 kW) and the specific cutting pressure, K-s (1700-3500 N/mm(2)). The tool wear t ype was identified and its evolution with cutting time was measured for dif ferent sets of cutting conditions, using polycrystalline diamond drills. Th e holes' surface finish was evaluated and very good results, exceeding stan dard values for drilling, were obtained (R-a between 0.25 and 1.2 mum).