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This paper presents the dynamic response of an air-bearing displacement sensor for on-machine surface form measurement of micro structures. The on-machine measurement system has some merits in terms of measurement efficiency and re-machining for error compensation after measurement. On the other hand, the performance of the contact type measurement system based on stylus methods is dominated by the dynamic characteristics of the system because the system is subject to random vibrations of the machine tool including the spindle during measurement. Therefore, the dynamic response of the system is useful for analyzing the mechanical vibrations of the practical on-machine measurement system. In this paper, the equation of motion for the air-bearing displacement sensor to the excited input displacement is derived and the displacement behavior of the system by using a PZT actuator is investigated within certain frequency ranges experimentally for identifying the dynamics of the system.

This paper presents the experimental results of investigating the performances of an air-bearing displacement sensor for surface form measurement of micro-structures, such as micro-lenses, on an ultra-precision machine tool. The sensor consists of a stylus for contacting the surface, a shaft for mounting the stylus, an air-bearing for suspending the shaft and a blade spring for applying the measuring force against the surface. At first, experiments were conducted on a vibration isolated table to identify the basic performance of the sensor for displacement measurement. Then, the sensor was mounted on a diamond turning machine for evaluating the performance of the sensor for on-machine surface form measurement of micro-lenses. A roll workpiece, on which a micro-lens array was fabricated by using a fast tool servo on the diamond turning machine, was employed as the specimen for the on-machine experiment of surface profile measurement.

The requirement of the ultra-precision machine tools for ductile cutting of hard brittle materials was examined experimentally. One of the essential factors of achieving ductile mode cutting was not only high-resolution feedback control but also the dynamic performance of the machine tool in forming solid immersion lens of monocrystalline silicon. We also proposed newly developed method for ultra-precision machine tools, which does not have enough high dynamic performance in order to achieve ductile mode cutting of the hard brittle materials. An additional device consisted of air slider on the machine tool was applied to cutting of glass in order to keep stable ductile mode cutting. We fabricated high-value added structure, which are designed a diffraction grating, consisted of micro groove on a borosilicate crown glass surface with the developed device.

This paper proposes a newly developed monitoring system for grinding ultra-precision small size casting die having asphericl surface. Small size aspheric glass lenses are widely used for IT industry. The lenses are cast in cemented carbide die because of its high melting temperature and the die is usually ground by small size diamond grinding wheels. The wheel can not be changed or dressed in finish grinding, because changing or dressing the wheel brings deterioration of die accuracy, therefore, very light grinding conditions must be adopted, such as less than one micrometer of depth of cut. In such conditions, monitoring of grinding state, such as that of grinding force, is indispensable to achieve high quality and high efficient grinding. However sensing of very low grinding force is quite difficult, because of the system stability and Signal/Noise ratio in the sensing. In the system developed, an induced current was applied to a closed circuit, which was consisted from die, diamond wheel, spindle, air bearing and machine tool, by a ring coil coupling with the circuit and the current was detected by an another ring coil. The current was depended on an impedance of the circuit, and the impedance was influenced by the conditions between die and grinding wheel, Stable or unstable grinding conditions was detected, so that high efficiency ultra-precision grinding was achieved by using the system.

In order to develop high efficiency finishing for guide ways of machine tools, hardened and ground die steel SKD61 was lapped by using a robot or a milling machine. Lapping, in general, is carried out on a machined surface to obtain fully flat surface, this means that the machined surface is lapped away completely. In this study, however, the purpose of the lapping is to make a surface having a superior wear characteristics without damage of the geometrical accuracy obtained by grinding. Gray cast iron and a layered soft disk made by a rubber, a sponge and an acrylic resin were used for the lap. It was found that lapping by the robot with gray cast iron lap was difficult because of many scratches and geometrical damage on the lapped surface, while lapping by the milling machine with the iron lap could get a fairly good surface finish without any geometrical damage except some scratches. The best surface finish was obtained by using the layered soft disk lap.

This paper presents the experimental investigations for performance evaluation of an air-bearing displacement sensor as a measurement system for nanometrology of surface forms by using it. The experimental configuration and some considerations for the air-bearing displacement sensor are described. Then, in order to identify the basic performance of the sensor, a measuring force and displacement output of the sensor are evaluated on a vibration isolated table. The sensor is also mounted on a diamond turning machine to evaluate the surface form of micro structures. A roll workpiece with Ni-P plating surface, on which micro-lens array are fabricated by using a FS-FTS (Force sensor fast tool servo) on the machine tool, is employed as a specimen for measurement.