Single crystal silicon carbide is a next-generation material for power devices, because these devices have higher breakdown voltages and operating temperatures. On the other hand, SiC is difficult to machine because of its high hardness. This paper proposes a combined polishing technology that generates relatively lower hardness material with UV irradiation and/or electrochemical process, and mechanically removes the material with abrasive grains. The hardness of the grains is higher than that of the generated material and lower than that of SiC. The SiC polishing experiment is carried out with the combined process. The polishing speed is from 10 to 50 times higher than the speed of the conventional CMP process.

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This paper focuses on numerical consideration of the path interval formula proposed in our previous report. The path interval formula was derived based on geometrical configuration suitable for flat surface machining; moreover, the advanced treatment was provided for freeform machining. The first report showed that the proposed formula had high flexibility for tool posture change in 5-axis flat end milling. In this second report, numerical investigation was intensively given to the path interval formula. The visual evidences were expressed with varying tool postures in 5-axis flat end milling, and the detailed discussion found the several characteristics which required special attention in the practice.

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In this study, high-speed steel drills 0.5, 1.0, and 1.5 mm in diameter are employed in drilling titanium alloy for basic drill failure data acquisition. First, the relationships between drilling depth, cutting force, and failure are investigated in conventional drilling. The cutting force is considered in three divisions: stability region, rising region, and unstable region. The relation of rising ratio of thrust force in the rising region of cutting force to drilling depth is clarified. Next, step feed drilling was examined for each drill diameter. Cutting force is also unstable as in the case of conventional drilling when drill failure occurred. Finally, the aspect ratio was more than 10 in step feed drilling with each drill diameter.

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Newly developed resin-based composites including nanofiller particles have been developed for use in dental clinics. The polishing procedure for nanofilled resin-based composites is special, because nanofiller particles have relative high hardness. Therefore, a multistep process for touch-up using several polishing tools is required to obtain a smooth surface on the composites with current polishing technology. Dentists and dental technicians require means of reducing the number of steps in polishing. A high-performance polishing tool has the potential to be able to bypass some of the steps in the polishing process. However, their polishing specifications are not yet fully understood. In this study, a polyurea resin-bonded mounted diamond wheel was developed for polishing nanofilled resin-based composites. Using this mounted wheel, polishing of five commercially available nanofilled resin-based composites was performed. The results indicated that a mirror-like polished surface could be obtained.

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