SUS316 has excellent corrosion resistance, and is therefore widely used for manifold units in food processing machines, medical instruments, and analytical instruments. With the miniaturization of manifold units, the demand for small-diameter cross-hole drilling of SUS316 has been increasing. The burrs formed at the intersections of holes in manifold units can cause contamination of the fluid flowing through them. Therefore, burr-free drilling techniques are required. This study was performed to examine the burr suppression effect of ultrasonic vibration-assisted drilling of SUS316. In addition, to clarify the mechanism of burr suppression, we investigated the effects of ultrasonic vibration on the metal crystal structure and hardness distribution in the area of the processing hole. The results indicated that ultrasonic vibration causes crystal refinement in the area, increases the hardness, and thus suppressing the growth of burrs.

XAFS analysis clarifies the relative compound ratios of oxides remaining on the 4H-SiC plane polished under ultraviolet irradiation and various polishing conditions. The final polished surface roughness should be less than 0.5 nm of Ra and 2 nm of Rz, and the amount of remaining oxide should have a relative compound ratio less than 1% on the polished surface. UV induces the production of SiC oxides and reduces the mechanical scratching action of diamond abrasive grains against the SiC plane polished using a fiber-type soft cotton pad. A net-like hard cotton pad can produce a smoother surface polished in Ra of 0.662 nm and Rz of 2.80 nm, and that has a relative compound ratio of oxides less than 10 %. The final polishing process was carried using 5-nm diamond powder and 5-μm CeO₂. Ultraviolet-excitation polishing achieves a very smooth surface with roughness below 0.5 nm in Ra and 2 nm in Rz. This polishing process minimizes the residual volumes that are less than 1 % of interface oxide and 0 % of SiO₂.

In this study, fiber bond grinding wheels containing nano-diamond were fabricated using a PELID technique capable of producing microfibers. The frictional coefficient of the fabricated grinding wheels was investigated, and the inclusion of nano-diamond was confirmed to reduce the frictional coefficient. Fiber grinding wheels containing nano-diamond using SD#2000 abrasives were also developed.