最近, 半導体工業分野などでは異なった物質を原子オーダで積層する超格子膜などが実現されている.このようにサブナノメータの極薄膜を形成する技術はオイルフリーの真空装置など技術開発の進展に伴いほぼ完成している.これらの薄膜形成技術の発展に伴い各種の薄膜が広く使用されるようになり, 精密機械の分野でナノメータスケールの薄膜が適用されているD.さらに最近ではマイクロマシソ, LSIパターンの修復など微細な薄膜を直接形成する必要性も生じており, エネルギーアシストCVD (Chemical VaporDeposition, 化学蒸着), SPM (走査型プローブ顕微鏡) などが適用され研究が進められている.
現在実用されているナノメータスケールの薄膜形成法について述べ, さらに研究開発が進められているナノメータスケールの微細薄膜形成技術を紹介した.読者の参考になれぽ幸いである.

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大型TFT-LCDディスプレイに用いる高精度なパターンの転写技術を開発する目的で, 凹凸球面反射ミラーとエキシマレーザを組み合わせた実験装置を試作し, 基礎的な転写実験を行った.その結果, 次のことが分かった.
(1) 試作した装置の限界解像力は, ほぼ理論値に一致し, 100mm角にわたって4~5μmまでのパターンの転写が可能である.
(2) 反射ミラー光学系の特性は, ミラー曲率半径や開口数によって異なるが, それらには限界解像度を与える最適な組合せがある.
(3) エキシマレーザ (XeF) は, 走査型転写光源として適用が可能である.

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Due to compact and light-weight design, modern machines are strongly suffering from vibration and induced noise. In order to solve the noise problem, the structure of machine is so complex as to be accuractely modeled, therefore an Acoustic Building Block Approach (ABBA) is developed where the structure is divided into several components and the total acoustic characteristics of the machine in terms of natural frequencies and acoustic mode shapes can be predicted based on the individual acoustic characteristics of each component. Numerical models for pipe structure using acoustic Finite Element Analysis are used to verify the effectiveness of ABBA. Also the basic consideration on experimental methods is discussed to provide accurate measurement on acoustic characteristics of component.

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The axial tension of the bolt in the plastic region tightening method depends on the yield point load of the threaded portion under the combined loads of the axial tension and the thread torque induced by the tightening. A new estimation method for the yield point load of the threaded portion is proposed taking account of the general yield criterion based on the rigid-plastic solution for combined loads. Considering the coefficient of friction at the flank of the thread and the residual thread torque after tightening, simple formulas are derived for the yield clamping force and the maximum additional axial tension under externally loading. It is confirmed from the experimental results obtained by a combined loading test that the proposed estimation method is superior to the conventional one taking into account only the local yield criterion. Upon applying the local or general yield criterion, the range of the initial clamping force is bounded between the elastic region tightening, the yield point tightening and the plastic region tightening.

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It is very difficult to eliminate the mechanical hysteresis for positioning lnechanism. Weneed the allowable mechanical hysteresis magnitude, when we improve the mechanism performance.So that it has been proposed the evaluation methods of mechanical hysteresis influences on dynamic performance using the mechanical hysteresis test unit. In this report, these methodsare expanded to apply for positioning mechanism with reducer, which the mechanism includesthe mechanical hysteresis characteristics in these control system. Especially, the Amm parameter is newly defined to evaluate the influence on the system stability. And then it is testedand evaluated the closed looP Positioning mechanism system with the “No-backlash Gearing” reducer and the “Mechanical Hysteresis Test Unit”. It is proved that it can be quantified theseallowable mechanical hysteresis magnitude as like as the only Mechanical Hysteresis Test Unitcharacteristics.

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Linear mechanisms have usually required some precisely finished guideways whose shapes are plane or cylinder. However, it is difficult to manufacture such guideways and to maintain their accuracy against wear. A linear mechanism developed in this paper consists of double Watt's links using spherical slide bearings. The spherical bearings can easily eliminate influences of misalignments and dimensional errors of the links on the accuracy. Moreover, the steel balls used as a guideway of rotational axis introduce high rotational accuracy and easy maintenance inexpensively. The main results obtained are as follows : (1) With the steel balls of sphericity 0.2 μm, the errors in the perpendicular directions of the motion were within 1 μm and changes of the pitch and yaw angles were within 1 second of arc, while the working length was 9 mm. However, moving path hysteresis was observed caused by friction in the contact parts. (2) The dimensional errors and the relative position errors of the links had little effect on the motion errors. (3) No link interactions were observed introduced by the angle errors and the misalignments of the rotational axes in the link mechanisms. (4) The wear of the balls and their supporting parts affects the moving accuracy.

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静圧式自動調整絞り付きスラスト軸受と排気制御絞り付きラジアル軸受とを組み合わせた高剛性エアスピンドルの特性を解析した結果, 次の結果を得た.
(1) スピンドル先端でのスラスト剛性をスラスト負荷240N以下の範囲において無限大にできた.
(2) スピンドル先端でのラジアル剛性をラジアル負荷15N以下の範囲において無限大にできた.
(3) スピンドルの回転精度を200rpm程度までの回転数範囲でスラスト方向で20nm以下, ラジアル方向で50~80nm程度とすることができた.
以上より, 静圧式自動調整絞り付きスラスト軸受は実用性の高い高剛性.高回転精度軸受であると言える.一方, 排気制御絞り付きラジアル軸受は負荷容量に改良の余地があると思われる.これらの軸受を組み合わせて試作したエアスピンドルは比較的低い回転速度と軽荷重において高い剛性と回転精度を持つことより, 超精密計測機器への使用が可能であると考えられる.

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This paper describes measurement of in-plane vibration using a laser speckle interferometer with double-aperture method. A new optical system, which transforms interference fringes in a speckle into a line image on a CCD linear image sensor with an additional cylindrical lens, was proposed. From an experiment to measure static displacement, it was revealed that the cylindrical lens acted to detect fringes two-dimensionally and to average the distribution of optical intensity as same as.scanning measurement and that the measuring accuracy could be improved by decreasing the influence of phase variation in the fringes. The interferometer was applied to measure the flexural vibration of a cantilever as an example, and the vibration displacement could be measured with 1.95kHz of sampling frequency and with 0.5μm of measuring error.

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This paper describes the method for the improvement of surface straightness in finishing of wire electric discharge machinings (Wire-EDM). In general, two kinds of shapes are formed on surfaces of workpieces ; that is, concave forms and convex forms. The mechanism of forming these shapes is strongly related to the mechanical behavior of a wire electrode. The wire electrode is vibrated by discharge reaction forces, and the irregularity of these forces makes the concave form on the finished-surface. The supply of intermittent voltages prevents long ignition delay time, so that it inhibits the variance of forces on the wire electrode. The simulation indicated reduction effects of vibration of the wire electrode in the intermittent voltage condition. Straightness of surfaces was also improved by the experiment in finish-machining.

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This paper presents a new method of surface modification by electrical discharge machining (EDM) using composite structured electrode. Composite structured electrode is made of green compact product or sintered product. Since the apparent thermal conductivity of the electrode is very low, the wear rate of the electrode gets so high that the substance of the electrode is implanted into work surface by EDM. Some experiments of surface modification were performed on carbon steel as workpieces by EDM with the composite electrodes in hydrocarbon oil. Copper, aluminum and tungsten carbide were used for the material of the electrode in experiments. It was revealed that there existed the electrode material in the work surface layer with the thickness of several tens micrometers. These surfaces have less cracks, high corrosion resistance and wear resistance.

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Grinding temperature has a significant effect on the grinding accuracy and surface integrity. Since the convective heat transfer coefficient α in the vicinity of the wheel to workpiece contact zone under wet grinding have hardly been known, reliable estimation of the grinding temperature have never been done. In this paper, the temperature distribution in a workpiece is calculated by using a finite element method where some models of the distribution of α, based on the results formally measured by authors, are utilized and film boiling phenomenon is also considered. Main results obtained are as follows : (1) In deep grinding, the film boiling occurs in the forward part of the contact zone. The boiling area sharply expands with the quantity of heat applied; (2) In down-grinding, since coolant is supplied directly to the forward part where the maximum heat flux is applied the cooling efficiency is higher than that in up-grinding. (3) Grinding heat partitioning ratio into workpiece under wet grinding is estimated at about 3 percent in deep grinding and about 30 percent in shallow grinding.

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The friction drive positioning system is composed of a motor, a drive roller, a driven slider and a linear scale for position measurement. This paper describes the effects of the normal force between the drive roller and the driven slider. It has showed that (1) Under a given positioning accuracy, a normal force exists which gives the minimum positioning time. (2) Adjusting the normal force during the positioning operation is effective to get higher positioning accuracy.

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This paper presents experimental results on micro-steps between different materials on polished work surfaces composed of Al₂O₃-TiC (HV_??_2200), sputtered Al₂O₃ (HV_??_990) and a magnetic material (HV_??_180). The micro-steps, inevitably, are generated from the difference in the stock removal rates of the composite materials. In order to decrease micro-steps, use of a finer abrasive grain and a polishing plate of lower hardness such as tin is effective. Furthermore, cutting the grooves on the polishing plate is more effective in decreasing the micro-steps because abrasive grain can be buried easily in the surface of the polishing plate. In the case of a tin plate with the grooves, the micro-step between Al₂O₃-TiC and the magnetic material can be reduced to less than one half of that for a tin plate without grooves. This value can be brought to 10 nm and less.

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High-efficiency die-sinking of a plane surface using a ball end mill has been developed to obtain high-quality dies with a finely-milled surface. Noticing the effectiveness of the high-feed cutting method equalizing the tool feed per tooth to the pick feed, investigated were the shapes of cutting tools appropriate for the method. To solve the problem of the milled-surface roughness resulted from machining marks and peeling off built-up edge by using conventional cutting tools, a new tool with superior cutting quality and excellent durability has been developed by eliminating the central end cutting edge. The developed end milling and cutting tool ensure the machining of resin-mold die steel at the feed rate of 4 m/min to make the surface roughness under 4 μm.

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This paper presents the development of an LED with an Fresnel lens to be used in an optical sensor. In a conventional LED a lens and an element are separated, and so must be aligned. Using an LED with a Fresnel lens, both parts are combined so alignment is not necessary. The Fresnel lens was developed because of its thin structure and good optical characteristics. Conventionally, the Fresnel lens has been fabricated by means of electron beam lithography, but it was very time consuming. To solve this problem and fabricate an LED with a Fresnel lens, a diamond turning machine was developed. This machine is used to fabricate molds for Fresnel lenses. By using these molds and inserting LED chips during the injection molding process, an LED with a Fresnel lens can be fabricated. Compared to a conventional LED with a spherical lens, the thickness of the LED is reduced by 70%, and its volume by 50%. Also the LED with a Fresnel lens emits three times as much light as a conventional LED. It is expected that when this LED is used in an optical sensor, its reduced thickness and good optical characteristics will result in a thinner sensor with improved sensitivity.

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A bowl feed double side polishing machine has been newly developed to produce silicon wafers with precise thickness in the mirror polishing process. This machine can detect intermittently the thickness of silicon wafers during polishing by means of ultrasonic waves passing through a hole of the lower polishing plate, and being reflected as echoes on both the bottom and the top surfaces of wafers. This machine is able to measure the thickness of wafers within 1 μm accuracy. Precise wafers with 125 mm diameter could be polished less than 3 μm thickness deviation and within 2 μm flatness without any surface defects using the developed polishing machine.

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This paper describes the development of Moving Coil Actuator for Automatic Piano. To obtain the desired tone volume, the servo system is performed by a follow-up control which uses the signal wave form. The capacity of the actuator has a torque of 1.33Nm/A, a thrust of 13.3N/A at the swing stroke point, and the frequency responses up to 60Hz. As a result of the experiments, the actuator is capable of generating enough force up to attain saturation of a movement of a piano's action, and of controlling a wide range of hammer struck string velocity down to the smallest tone volume. Also, the optimum signal wave form is found by analyzing the motion of the key and the hammer. The actuator is realized to produce the stable tone to the smallest tone volume and to perform the repetition of the sound pressure range of about 18 dB at 15 Hz.

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For understanding of nanometric chip removal process and in quest of extreme machining accuracy attainable, a carefully controlled microcutting experiment of electroplated copper was carried out on the-state-of-the-art experimental cutting machine and diamond cutting tool. Following a brief look at the significance of the minimum thickness of cut, which is defined as the minimum uncut thickness of chip removed from worksurface at a cutting edge under an ideal operation of machine tool, the chip morphology observed with high resolution scanning electron microscope (SEM) is discussed. SEM observation shows that the stable shear-banded chip can be removed even at nanometric uncut chip thickness. The chips are corrugated and folded due to the intermittent buckling of chip. Judging from the facts that the thickness, lamellar spacing and folding interval of chips continuously decrease with the uncut chip thickness, the mechanism of nanometric chip removel process seems to be same as that of conventional cutting. Finally, careful analysis of the experiment shows that the minimum thickness of cut of 1 nm can be expected in the microcutting of copper.

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The functions to evaluate the machinability of ceramics in grinding, honing and superfinishing are derived theoretically, assuming that one stone (wheel) corresponds to a single point tool with a long cutting edge. The dimensional analysis is employed to investigate the effect of physical properties of the ceramic material on its machinability. Work materials used in experiments are Al₂O₃, SiC, Si₃N₄, ZrO₂ which are sintered under atmospheric pressure, Mn-Zn ferrite and SiO₂. The main results are as follows. The machinability of the ceramic material depends on not only its physical properties but also the method of machining. For the work materials of Al₂O₃ and SiO₂, the honing is superior in cutting ability to the grinding. In grinding and superfinishing the strong relation is observed between the energy release rate of the ceramic and its machinability, but in honing it is observed between the hardness of the ceramic and its machinability.

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