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Binderless nano-polycrystalline diamond synthesized by direct conversion of graphite under high pressure and high temperature has a very fine texture consisting of small diamond grains of several tens of nanometers, having extremely high hardness, no cleavage and high thermal stability. Precision cutting tests on various cemented carbides were performed under different conditions. The results revealed that the cutting performance of binderless nano-polycrystalline diamond tool is much higher than those of conventional polycrystalline diamond tool and single-crystal diamond tool. The reasons of its high cutting performance are discussed based on the wear mode and the material properties.

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Demands are increasing in recent years for high hardness press metal mold in order to increase the life of the mold. The metal mold is generally finished by cutting and subsequent finishing processes after hardening. It is required to replace the steel mold material to the cemented carbide which has higher wear resistance. While it is required to cut the cemented carbide effectively to manufacture the carbide mold, the cutting technology of cemented carbides is not yet established due to short tool life. The experimental test results of cutting of carbides containing different cobalt binders with sintered CBN tools are presented in the present report.

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As an air bearing lead screw has a great advantage of accurately transforming rotational motion to linear motion due to no friction, no backlash and no hysteresis, precise positioning of a stage can be realized by a precise rotational motion. We developed a positioning controller with servo sampling rate of 10 kHz that employed FPGA (Field Programmable Gate Array) and applied it to positioning an air bearing stage by a semi-closed loop control. We obtained 5 pulse/step (less than 10 nm/step) positioning.

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Smoothness of the reference motion trajectories carries great importance for tracking performance of CNC feed drive systems. Acceleration kinematics of conventional trajectory generators has rich frequency content. Actual feed drive system, on the other hand, contain various structural flexibilities and resonances. Thus, the reference trajectory may excite those poorly damped flexibilities, and cause residual vibrations during point-to-point motion on CNC systems. This work investigates the effect of trajectory's jerk parameters on the oscillatory behavior of drive structures. In particular, analytical formulations are derived to compute the optimal jerk parameter of the reference trajectory so that resonances in the feed drive system are not excited. It was shown that that by tuning the jerk time, damping of resonances could be achieved.

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Recently, the nanoscale positioning of table is frequently required for industrial applications and there have been developed many positioning methods. However, there are still left a lot of problems to be investigated related to dynamic range, accuracy fluctuating by thermal expansion, physical vibration and so on. Under the situation, high precision positioning has been often tried successfully utilizing the friction property between contact surfaces because the principle is very simple. In this study, utilizing and the tangential micro-displacement characteristics including the friction property, a basic idea is proposed for developing the positioning system.

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A smooth impact drive mechanism (SIDM) is a linear actuator which utilizes the friction force between a friction bar and a moving object. In the previous researches, SIDM actuators were composed of a soft type multilayered piezoelectric element which can generate a large piezo electric displacement. However, it has a complex structure and the piezoelectric material has low Q value. Therefore, we proposed to utilize a resonant phenomenon for SIDM principle. In this case, the driving part is a hard type piezo element while enables to drive an actuator with large speed efficiently. In this study, we propose to make it possible to adjust resonant frequencies of a vibration element, and to design a resonant type SIDM actuator with a hard type single-layer piezoelectric element.

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When multilayer electrostatic actuators are supported by only lubrication oil, the friction characteristics of the actuators are greatly influenced by their driving signals. The features of actuators enable the actuators to have two driving characteristics, that is, high response with a wide working range under the low friction condition and precise motion with a large holding force but a short working rage under the large friction condition, without additional mechanisms. This paper describes the driving signals for switching these characteristics and ultra-precision positioning performance using the driving signals.

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It is possible to control polishing slurry's dispersibility with dispersants for glass materials. Based on experimental results of the controlled dispersibility and polishing performance of polishing slurries, effects of the combinations of the dispersibility and polishing pad surface statuses on polishing performance, and possible polishing mechanism has been studied.

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This paper discusses influence of polishing pressure on polishing characteristic of optical glass. First, the polishing conditions and equipment are described. Next, the relationship between the polishing pressure and removal rate, and moreover the relationship between the polishing surface roughness of polishing surface are investigated experimentally. Lastly, influence of the polishing pressure for the optical glass is verified.

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