1982年開催の日本国際工作機械見本市 (第11回) で, 主軸回転数が毎分1万回転を越えた機械が3台出展された.15年経過した現在, 高速加工への関心が高まっており, この種の加工機が少しずつ普及している.また, 高速加工とりわけ高速ミーリングに関する基礎研究も開始されており, 加工精度, 加工面性状, 切削力, 工具寿命, 切削温度等の加工特性が少しずつ明らかにされている.本文は著者らが検討を行ってきた内容を要約して示したが, 工作機械メーカにおいても様々な取組みを行っており, 前述の技術講演会のテキストにはその内容と多くの加工事例が紹介されている.また, 著者の一人 (賀井) が所属する金型メーカにおけるプラスチック金型への適用事例 (図9) では, 加工後に磨き工程をほとんど必要とせず, 加工時間の大幅な短縮に予想以上の効果があることが明らかにされている.
一方, 中川はボールエンドミル加工が高速加工に適した加工であり, 図10に示すようにCBNを工具材料に用いれば, 近い将来高硬度材に対して切削速度1000m/minの超高速加工も可能になると予測している.しかし, 超の文字が付かなくても吉田が指摘するように高速加工技術は奥が深く, 今後高速・高精度加工を一層普及, 発展させるためには, 工作機械ならびに制御装置に関係する技術的な課題に加えて, 工具に関しては長寿命を実現する材料, コーティング技術, 切れ刃形状, 保持具に関しては偏心が小さく, 高速回転時においても十分な把持力とパランスの良いチャック, さらには効率的な工具経路を出力するCAM等検討すべき多くの課題も忘れてはならない.同時に, それらの課題を解決または改善するためにも, 高速・高精度加工に携わっている多くの研究者, 技術者による基礎研究を通じた様々な試みおよびその結果得られる貴重なデータの蓄積と公開がとても重要であると考えている.

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Rapid prototyping technologies have been used in the manufacturing industry. They are particularly useful for evaluating aesthetic characteristics of product surfaces designed by CAD systems. In such situation, it is often the case that the geometric model represents only the outer shape and does not have the inside shape. Consequently the inside of the physical prototype generated using such geometric model is just filled up with material. It is wasteful with regard to manufacturing time and material volume. The aim of this research is to make a cavity by generating an inner shell geometry based on the outer surface in order to eliminate such unnecessary volume. This operation is called “shelling”. It can be performed by offsetting surfaces. However, it requires complex surface intersections. This algorithm adopts vertex offsetting which is simpler and may be robust. It is shown using some examples, that shelling is useful for reducing shaping time and material volume.

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The number of lower limb disabled people have lately been increasing because of traffic accidents and aging society. Most of the lower limb disabled people daily live on wheelchairs. Stairs and step are considerable obstades for the people whose living depends upon wheelchairs. Although stair climbable robots have been developed as robots for extreme tasks, they are of large size, and heavy weight, and too forceful for stairs at home or hospitals. Therefore they are not suitable for welfare purpose at home or hospitals This study aims at the development of stairclibing wheelchairwhich offers assistance to the lower limb disabled people. The stair dimbingwheelchairhas been develop edfor welfare purpose. The second report described hou to develop stair climbing mechanism of leg and wheel type wheelchair. This report describes how to succeed in automating stair dimbing by loading new developed measurement system on the stair dimbing wheelchair.

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The purpose of the study is to develop a method to control the armature current of the DC servo motors effectively and safely in the case of over-rated driving of the motors for realizing quick motion of robots. A method of variable frequency PWM (Pulse Width Modulation) has been developed both to suppress the rush current generated at the starting and to prevent the decrease of the effective value of the current. To apply the method to quick driving of a robot leg with three joints, the mathematical model with similar responses has been derived, and experiments on the model has been performed. The results have shown the effectiveness of the method.

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本研究の結果, 水作動液を用いた静圧軸受では, 従来の油の式を用いると定量的にも定性的にも大きく異なることが分かった.特に水作動液における円筒形絞りでは, 線形関係が成り立たず, オリフィスの式に近いことは油の場合との大きな違いである.
また, 静圧軸受設計の基本となる供給圧, 入力絞り, 軸受すきま, 流量間の関係が, 水の場合について定量的に関数関係で求めることができた.これによりリセス圧が求められ, 軸受特性に重要な性能である軸受容量と剛性, その際の必要流量を計算で求める方法を明らかにすることができた.

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干渉じまの解析における位相シフト法の高度化をはかるために, 微小位相差測定時の量子化の影響について注目し, 局所サンプリング法を提案した.本稿では, シミュレーションにより干渉じま強度変化の振幅および測定位相の変化に対する位相誤差の関係を調べ, 本手法の微小位相差測定に対する有効性を確認した.また, 偏光干渉計および干渉顕微鏡を用いた実験により, 微細表面形状の測定には本手法が有効であることを示した.

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An automatic in-process detection system for narrow and short cracks in dark PZT plates used for piezoelectric parts has been developed. A crack in a dark PZT plate is difficult to detect because the diffuse reflectance of PZT is very low compared with that of an alumina plate. With this system, the contrast and SN ratio in the crack detection signal are improved. The former is improved by using a polarized beam splitter for separating the incident light beam from the reflected light beam. The latter is improved by illuminating the PZT plate with the optimum radiant flux of a laser and by setting the detection window at an optimum position. The 0.2 mm-long cracks with 1 μm and 3 μ m in width, are detected at 50% detection reliability and 100% detection reliability, respectively, using the laser scanning system developed for the in-process inspection.

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Basing on the optical cutting technique, this study aims to develop an accuracy measurement method of tooth profile for minute module gears. This report, as a sequel of the previous report which made possibility of this method clear, deals with subjects with regards to a practical step to actual tooth profile measurements. The object to be measured is a range except tip and root portions of tooth surfaces of a hob-cut spur gear with 0.2 module which is considered to be in measurement limit in using a touch probe type instrument. Profile errors are acquired in comparison between fine-lined image data of tooth surface filtered through a low pass filter to eliminate influences of surface roughness and so on and the theoretical tooth curve. It is ascertained that adequate measurement results in accuracy of micro meter level can be attained. However, for further development, it is necessary to find solutions for the following problems, namely influences of surface roughness to the image data and use of the polarized light technique.

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本研究では, 試験片試験機系の自由エネルギーの議論に基づき。セラミックスの破壊じん性試験におけるき裂の安定条件を検討し, その結果に基づいて, SEN三点曲げ試験片の安定破壊が可能な卓上型試験装置を開発した.この装置は, 試験片の準備や試験手順を簡単にするため, 製作が容易なJIS R 1607型の曲げ試験片を用いるとともに, クラックスタビライザ等の付加装置を必要としない設計にした.
一般的なエンジニアリングセラミックス4種 (Al₂O₃, Y-PSZ, SiC, Si₃N₄) を試験片として, その性能を確認したところ, すべての材質において安定なき裂進展を実現することができ, 荷重変位曲線の記録に成功した.
水晶式力変換器を用いた荷重測定は, 一般には長時間の安定性が保証されないが, 本実験における誤差は5～10%以下と推定されるので実用上許容される範囲であると認められた.

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Working force or temperature irregularity induces the deformation of the structure of an operating machine; the operational information can be obtained from the structural deformation. The authors designed, fabricated and evaluated a “structural deformation sensor” to obtain operational information. It is composed of two elastic blocks fixed on the structure and a rigid connecting bar combined between the two blocks; strain gauges attached on the parallel plates in the block can detect the displacement discrepancy between the connecting bar and the structure with a 0.1μm resolution. With the connecting bar made of the same material as the structure, deformation induced by working force can be measured; with the bar of invar alloy, thermal deformation can be done. Through its applications to various machines, we could obtain the following operational information : working forces of press machines and excavators, stock weight of silos, thermal positioning errors of grinding machines, machining centers and coordinate measuring machines.

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This paper describes the performance of the high-pressure abrasive jet machining (AJM) system and the relationship between injection and machining characteristics on drilling of quartz workpiece. AJM process is similar to the sand blasting, and effectively removes hard and brittle materials such as glass and ceramics. AJM uses fine abrasive powders and small nozzles whose inner diameter (ID) is below 1mm. As the abrasive jet stream from the nozzle is focused onto the workpiece, small holes or slots can be machined easily. Impact velocity V_p0 (velocity of abrasive before collision) and density of impacting abrasives n (frequency of impacting abrasives per unit area) are measured through a laser Doppler anemometer. Results are as follows : (1) Impact velocity V_p0 is proportional to the 0.23 power of carrier gas pressure P_c in the mixing chamber of the AJM unit. (2) The density of impacting abrasives n is constant and independent of P_c in a large ID nozzle. In a small ID nozzle, the value of n decreases in smaller P_c (3) As the gap between nozzle and workpiece increases, the value of V_p0 increases and the n decreases. (4) The larger value of P_c and the smaller supply of abrasives are, the straighter hole can be drilled. (5) Stock removal.rate is proportional to the 3.7 power of impact velocity in this experimental condition.

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Ablation phenomena of material induced by laser irradiation are complicated and it is unjustifiable to analyze them theoretically with a continuum model. In this study, atomic behavior of copper, aluminum and silicon during laser ablation is simulated applying molecular dynamics. Variation of atomic array and stress state of atoms during and after laser irradiation are shown visually. Main conclusions obtained are summarized as follows : (1) Thermal shock wave travels to interior of material with laser irradiation. Propagation velocity of thermal shock wave is equal to elastic wave velocity. (2) In ablation process, many small voids generate in the liquid phase at first. Then they become larger and larger, and adjacent voids combine each other, which develop into a relatively larger void. Finally, the vicinity of surface bounds out forming into a relatively large lump. (3) In metal, fusing atoms flow out from the molten pool and deposit around the hole by viscosity and surface tension. In silicon, on the other hand, vaporizing atoms fly to bits after interacting or colliding reciprocally, then a part of them adheres on the surface, especially deposition around the hole is remarkable. (4) The surface of generated wall of silicon is rougher comparing with metal.

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Tool face temperature of single crystal diamond in high precision orthogonal cutting of aluminum and copper is measured using two-color pyrometer with an optical fiber. The infrared rays radiated from the chip-tool interface and transmitted through the diamond tool are accepted by an optical fiber and led to two-color detectors of different spectral sensitivity. Temperature distribution on the tool face is analyzed by employing finite element method and calculated results are applied to the estimation of the maximum temperature on the tool face. The results obtained are as follows; (1) The technique developed is suitable for measuring the tool face temperature in single crystal diamond cutting. (2) Output wave of temperature was clearly recorded. The tool face temperature measured is approximately 190°C for Al and approximately 220°C for Cu when cutting speed was about 620m/min. (3) The temperature increases with the increase of cutting speed. (4) The temperature on the tool face measured is in good agreement with that calculated.

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In this research, a method for the precision machining of soft rubber (50IRHD hardness), which is difficult by conventional grinding, has been proposed. In view of the unique behavior of various kinds of rubber when subjected to machining, i.e., strong effects of their dynamic properties, the authors have considered that rubber can be successfully machined with good precision by means of tools having a large positive rake angle and using high-speed intermittent cutting. More specifically, the authors assumed that high-precision machining of soft rubber could be realized using the high-speed milling method. As a first step of the study, the authors have carried out high speed milling of various types of soft rubber with end mill tools. As a result, the authors have found that the higher the cutting speed or the larger the rake angle of a tool, the higher the precision, the lower the surface roughness and the better the flatness of workpieces, thus proving that this high-speed milling can be used as a new method for the precision machining of rubber.

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Among various manual machine tool operations, it is known that the efficiency and accuracy of small-diameter deep-hole machining with a drilling machine is strongly dependent upon operator's sensitivity and skill learning level. In our previous work, a simulator of the drilling machine operation under no deflection of the drill was developed and its performance as a skill training apparatus was discussed. In this paper, the improvement of the simulator has been investigated. Firstly, the simulation model considering the deflection of the drill has been derived. Secondly, the model parameters have been reasonably identified from the experimental data of actual operation by applying the optimization technique due to genetic algorithm. In addition, the hardware system has been also improved to avoid reduction of realistic feeling which results from complicated calculation of the model.

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Dissolved oxygen in the ultrapure water has been known to oxidize Si wafer. In EEM, ultrapure water is also employed as a carrier fluid of ultra-fine powders. Oxidization properties of Si (100) wafer surface under EEM setup were investigated in this work. An oxidization with the growth speed higher than several 10nm/h was observed. The distribution of the oxide film thickness seems to depend strongly on the flow pattern on the Si wafer surface. The high speed oxidization observed in this work was understood to concern both to the extent of shear flow rate on the Si wafer surface and to contents of not only dissolved oxygen but also OH^- ion in the ultrapure water.

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The purpose of this research is to develop a new technique of CAH (cavitation aided honing) by which the workpiece can be easily finished in a fine surface with a very simple apparatus. The machining fluid, that is mixture of abrasive grains and water as carrier is sucked by a pump, and the flow of machining fluid is controlled by a restrictor, and then the cavitation phenomenon locally occurs by the rapid decrease of carrier pressure, so that abrasive grains in the mixed fluid come to interfere on the surface. In this report, the possibility of applying CAH to precision machining is investigated by analyzing surface finish, stock removal and behavior of carrier. Main conclusions obtained in this paper are as follows ; (1) Action of abrasive grains onto the surface in CAH is induced by very fine vibratory impact caused by cavitation occurred in the lower part from the center of restrictor in a flow. (2) At 2.0mm in clearance, cavitation impact of carrier becomes strongest, so that the stock removal and the decrease of surface roughness have maximum. (3) CAH can be applied to an ultraprecision machining by which the surface finish of Al-Mg alloy is improved from 7.3nm R_a with ultraprecision cutting down to the surface finish at 6.6nm R_a.

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This paper describes the development of grinding fluids that contain extreme-pressure agents of non-chlorine type and are soft for enviroment. The grinding performance of grinding fluids is measured by cylindrical plunge grinding in this case. The following experimental results are confirmed : (1) Grinding fluids excel in grinding performance when the content of lubricating component are more than 72wt% in prescription. (2) It is confirmed that grinding fluids soft for enviroment obtain used sulfurised sorbitan oleic acid ester instead of chlorine derivatives as extreme-pressure agent.

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It has been aimed to develop porous metal bonded diamond wheel with an ideal bond bridge like a vitrified bond, the pore rates of about 50 vol% and the bending strength of 10 to 50 MPa, because a lot of merits, such as low grinding temperature and a few grinding force, many chip pockets and easy dressing and truing, may be obtained. The following conclusions are obtained by some treatments. (1) The phosphorus diffuses into bond bridge with oxygen by heating after the phosphorating treatment. (2) The shear strength of bond bridge and the elastic modulus of bending test pieces increased by the heat treatment under high pressure by the diffusion of phosphorus and the subzero treatment by a martensite transformation of metal. (3) The original targets of development of porous metal bonded diamond wheel are accomplished with such treatments.

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