The drilling of microholes with a diameter smaller than 0.1 mm by grinding, which has not been reported previously, was attempted. Cemented tungsten carbide micropins were fabricated by electrical discharge machining and used as grinding tools. These micropins can be employed for grinding because discharge craters formed on their surfaces act as abrasive grains of grinding wheels. Workpieces were ultrasonically oscillated to decrease grinding force, because ultrasmall-diameter tools were easily broken. Helical tool feeding was also employed, where tools were moved in planetary motion. Microholes 30 μm in diameter were successfully drilled in crown glass. Ultrasonic oscillation decreased grinding force, although no effect of helical tool feeding was observed.

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To make a grinding wheel for nano-precision grinding, it is necessary to achieve fine-grained and uniformly dispersed abrasive grains in the bonding material. Such well-classified uniformly dispersed diamond abrasives and bonding resin particles were obtained using the method proposed in the previous report. An ultrasonic press machine was then developed to fabricate denser grinding wheels, and the grinding performances of two types of wheel were evaluated in this study. Compared to the conventional wheels, the grinding ratio was increased by threefold and the surface roughness was decreased by 60% using the developed wheels.

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In developing chamfering equipment for cylindrical parts made of tungsten carbide, fundamental research was performed using the quality engineering method. The conclusions are as follows. (1) Fine grain size has a large effect in reducing grinding force in the direction of the grinding wheel spindle. This large effect on reducing grinding force in radial and tangential directions cannot be maintained even with changes in processing conditions. (2) Low feeding speed condition is a large effect factor in reducing grinding temperature of wheel surface. (3) Long dwell time is a large effect factor for chatter form suppression. The above knowledge was utilized and trial production development of the chamfering equipment was carried out.

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In turning operations, the tool surface is continuously in contact with workpiece during the process of cutting, which makes it difficult to supply cutting fluids to the tool-chip interface. In addition, turning operations frequently generate long continuous chips that negatively affect both the machine tool and the machinist. To resolve these problems, vibration cutting with low frequency vibration generated by the NC program was developed in this study. A series of turning experiments for aluminum alloy were conducted to investigate the relationship between vibration conditions and cutting performance, and to evaluate the effects of cutting fluid in vibration cutting. Based on these results, a cutting tool with a micro-textured surface was applied to vibration cutting of aluminum alloy. The results indicated that chip adhesion on the tool surface was significantly suppressed even under higher efficiency machining conditions using the developed tool.

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