In this paper, in order to realize large displacement micro-stages, we propose a serially-arranged, electrostatic comb-drive XY-stage. We discuss the design and fabrication process of a metal sputtered PMMA micro-actuators. The micro XY-stage, which was fabricated by this research, was made with the LJGA fabrication process. It has serially arranged electrostatic comb-drive actuators. The designed single unit size of the XY-stage, including electrodes, is about 5 mm square, 100 μm range in the horizontal direction is serially arranged, while the vertical direction is 50 μm range with a single comb set. The movable range was determined theoretically and experimentally.

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Fatigue properties of 100 nm thickness-DLC and CNx coatings which were made under different coating conditions were evaluated with an AFM micro-fatigue test which was developed by authors. Higher ion energy of assisted ion as Ar and N for DLC and CNx respectively provided smaller hardness and shorter life. When assisted ion energy is relatively high, the depth of delamination wear scar is equal to the depth of maximum tangential stress. However, when assisted ion energy is relatively small, the depth of delamination wear scar is different from the depth of maximum tangential stress.

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This paper describes the stability of water-lubricated conical bearings with spiral grooves for high speed spindles. The bearings are intended to apply to spindles for drilling small holes of printed circuit-boards. Pressurized water is first fed to the inside of the rotating shaft and, then, supplied to spiral grooves through feeding holes. Therefore, water pressure is greatly increased at the outlets of feeding holes due to the centrifugal force by shaft rotation. In addition, water pressure also increases by viscous pumping effect of spiral grooves. The threshold of instability is theoretically predicted and calculated results are compared with experimental data. It was found that conical bearings treated in this paper have excellent stability at high speeds.

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