Simultaneous cutting and grinding of micropins using cylindrical microtools

Decreasing cutting force is always crucial in cutting processes. One method to achieve this is by minimizing tool wear, for which rotary cutting is a highly effective technique. The use of a cylindrical tool offers the additional benefit of easy tool fabrication, which is especially advantageous for a microtool capable of machining micropins. However, there have been no reported studies on rotary cutting using a cylindrical microtool. It should be noted that if a microtool is fabricated by electrical discharge machining, it is expected to engage in cylindrical grinding as well. This suggests that both rotary cutting and cylindrical grinding can be carried out simultaneously; however, there have also been no reported studies on simultaneous cutting and grinding. Therefore, the present study investigated whether this machining method can perform micropin machining, if it actually involves both cutting and grinding actions, and whether the combination of these actions enhances material removal capability. In turning and grinding experiments, where only one of the tool and workpiece was rotated, both actions were observed. Furthermore, it was confirmed that micropin machining can be performed by rotating both the tool and workpiece, resulting in a decrease in machining force to approximately one-quarter to one-half compared to that of turning. This indicates that simultaneous cutting and grinding was carried out, and the overlap of their actions enhanced material removal capability. In addition, the relationship between the machining conditions and machining force was investigated. At a small depth of cut, a tool with smaller surface roughness exhibited lower machining force than a tool with larger roughness, and the opposite was true at a large depth of cut. Finally, an ultrasmall-diameter micropin with a diameter less than 3 μm was successfully machined using conditions capable of reducing machining force.