The multi-wire saw is used in processing to slice brittle materials with a thin wire tool and slurry. This multi-wire saw usually uses a slurry consisting of mixed processing oil and SiC grains. The slicing of sapphire ingot has attracted a great deal of attention due to the common adoption of LEDs. As sapphire is harder than silicon ingots, the multi-wire saw using SiC grain slurry cannot be used to slice the ingots. Therefore, slicing with a multi-wire saw that uses diamond grain slurry is examined. This study considered the relation between basic slicing characteristics and the characteristics of diamond slurry, such as the viscosity of the base oil, sedimentation of grains, and the shape of diamond grains. The results indicated improvements in surface properties using this multi-wire saw with diamond grains.

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In dry grinding of carbon, dressing has been carried out at short intervals because of loading over a short grinding time. However, frequent dressing causes a decrease in production efficiency. Previously, we proposed the dressless restoration of grindactivity in which loaded chips are removed by peeling off adhesive tape from the loaded wheel surface after a roller press. In addition, buried abrasive grains in carbon chips were shown to project again on the wheel surface in the proposed method. In this report, the effect on regeneration of grindactivity in loaded wheels was verified by application of the dressless method, analyzing stock removal of the workpiece, the grinding current, and the surface roughness in grinding tests of carbon.

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Machining fluid containing various chemicals, including oil and extreme-pressure agents, etc., is used for conventional machining. This leads to high costs and harmful effects on the environment due to the discharge of large amounts of CO₂. In this investigation, the electric rust preventive machining method that uses only water as the machining fluid was developed to resolve the environmental problems. The supporting electrode was developed to achieve more effective rust prevention. Moreover, rust prevention of the electromagnetic chuck and workpiece and the optimized rust prevention current of the electromagnetic chuck and workpiece were verified using the supporting electrode. The results indicated that optimized rust prevention of electromagnetic chuck and workpiece could be achieved with a very low electrical power consumption of 0.62 W (0.1 A × 6.2 V, one workpiece, h20 mm pool electrode, and contact-type supporting electrode) to 2.0 W (0.2 A ×10 V, two workpieces, h20 mm pool electrode, and contactless-type supporting electrode).

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