This study was performed to examine the characteristics of thread cutting when using a TiSiN-based coating thread mill, which is a thread cutting tool, and using the helical interpolation motion of a machining center. The cutting force measured using the wireless holder was confirmed on the polar coordinate display. As the work material, carbon steel S50C, which is an industrial material for general use, stainless steel SUS310S, which is considered to be a difficult-to-cut material, and titanium alloy (Ti-6Al-4V-ELl) were used. Measurements were taken with a wireless holder and a thermography camera. The results indicated that the processing temperature of titanium alloy, which is a difficult material to cut, tends to rise, but the cutting resistance decreases. The relationship between changes in cutting conditions of titanium alloys and cutting resistance was clarified.

In this study, we propose a mirror surface finishing method using a spherical polycrystalline diamond (PCD) rotary tool to efficiently finish cemented carbide mold cavities by CNC machining, such as using a machining center. A tool with a ball diameter of ∼ 0.5 mm was trial-manufactured and investigated with regard to chip removal condition, roughness of the finished surface, and changes in internal structure. The results showed that a mirror finish with a surface roughness within 20 nmRa could be achieved, flat-type chips were generated, and with little damage to the structure under the finished surface.