Performance of micro PCD drills in drilling into SiC and effects of ultrasonic vibration

The present paper deals with the micro drilling into silicon carbide (SiC) with micro polycrystalline diamond (PCD) drills. Micro PCD drills with a nominal diameter of 300 m were fabricated by wire electrodischarge machining and they were used to drill into SiC test pieces with or without ultrasonic vibration. In the drilling test, performance of drilling into SiC was investigated. As the result of the drilling test, it was possible to make holes with good shape under all conditions. Large feed condition led to large chipping around hole entrance, bad surface roughness of hole wall and a shortened tool life. On the other hand, effects of ultrasonic vibration on chipping, surface roughness of hole wall, chip form and tool life were unclear, but the surface appearance of holes drilled with ultrasonic vibration did not seem to be affected so much by increase of feed.