Fabrication and cutting performance of cemented tungsten carbide micro-cutting tools

We have developed cemented tungsten carbide (CTC) micro-cutting tools of 3 mu m diameter by electrical discharge machining (EDM). Microdrilling and micromilling were carried out using the developed tools, and their cutting performance was investigated. Cutting was performed in free-cutting brass plates. Ultrasonic oscillation was employed to lower the cutting resistance. As a result, holes and a slot of 3 mu m depth were successfully fabricated using tools made of CTC with 0.6 mu m grain size, indicating that successful cutting with 3 mu m-diameter tools was accomplished for the first time. Furthermore. CTC with 90 nm grain size was used as a tool material to improve the tool breakage resistance and tool form accuracy. The drilling performance of tools made of this ultrafine-grain-sized CTC was also investigated and found to exhibit a considerably improved average tool life. (C) 2011 Elsevier Inc. All rights reserved.