企業の現場では,CAD/CAMに対する課題を解決するとまた新たな課題が現れるということを繰り返し現在のレベルに至った.その意味で今後もいくらでも課題はあるといってよい.少なくとも筆者の経験では,今までこういったことについて学会と産業界が真剣に議論することはほとんどなかった.その意味で今回の特集はその場の一つとして有意義ではないかと思う.設計理論やCADは形だけの産学共同では真の問題の発掘や解決ができない分野であると思う.更に相互の理解を深めるため徹底した議論葛藤,対決を通して新たな共通理解と具体的な共同研究や開発の実現を期待したい.
残念ながら今までは各企業での専用の優れたCAD/CAMシステムはあるが,世界に通用するCADのソフトウェアが日本から生み出されるということはなかった.日本のソフトウェア技術は遅れているといわれるが,せめてCADの分野でも学会と産業界が一体となり(例えば大規模なプロジェクトを作ってでも)世界をリードする新しい実用ソフトを日本から産み出したいというのが長年この分野の開発に携わった筆者の切なる願いである.

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A form-feature based representation Of mechanical products is essential to develop more useful CAD/CAM systems. Although a large number of studies have been made on modeling form features, there still remain many unresolved issues. In this paper focus is brought into additive features of which typical examples are holes, slots and bosses. Since those features are added to or subtracted from the shape of the product, modeling approaches based on boolean set operations are often taken to implement the feature modeling system on top of a solid modeling system. It is discussed that those approaches have problems that are mainly caused by interactions between form features. A new CSG based modeling framework is proposed in which we can explicitly describe and control those interactions.

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The purpose of this study is to develop a flexible machining system based on non-contact digitizing data of a master model. This paper presents a procedure of generating a cutter path for each surface element, which consititutes the master model. The procedure is as follows: (1) A master model is decomposed into some surface elements. (2) A surface element is fitted to quadric surface, and the quadric equation is transformed to NURBS equation. (3) An offset surface is created by the Inverse Offset Method which is available for any tool shape. (4) To generate a cutter location data (x, y, z), the coordinate x and y are calculated from NURBS equation, and the coordinate z is obtained by the offset surface.

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本報では,任意の接線ベクトルを拘束する曲率変化の滑らかな曲線を生成する方法を提案した.両端での拘束条件が厳しいため,指定できる接線ベクトルの変更範囲は限定されることがわかり,この範囲内について,デザイナの形状制御により滑らかな曲線形状を得ることができる.さらに,求められた2投影面上の平面曲線から空間曲線を生成する方法を提案した.これにより,空間曲線を曲率変化が滑らかでほぼG³連続となるNURBSで表現できた.

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Engineering drawings on paper have several disadvantages; they require a large storage space, are subject to deterioration, and are difficult to reuse. Several systems have been proposed to convert drawings to computer data. Most of them, however, rely on simple bottom-up algorithms and are very time-consuming because they must depend on human intervention for resolving recognition bottlenecks. Here, an automatic recognition system of mechanical engineering drawings for this paper-CAD conversion is proposed. It utilizes an enhanced bottom-up scheme for component recognition and a top-down scheme to identify valid component structures. Processing units are realized as individual experts and are integrated using a blackboard data system. This structure makes the proposed system robust to both noise and variations of drawings format and allows parallel implementation. Experimental results show that the system works well on the drawings with connected elements such as character strings and dimension lines.

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A major concern of mechanical designers in tolerancing, is understanding effects of geometrical errors on product's functionalities. The following three steps of tolerancing procedures with computers are necessary: 1. generate error models for nominal models, 2, analyze the effect of geometrical errors. and 3, determine tolerance specification and change the nominal shape models. In this paper, the second issue is discussed. Amongst various functionalities of mechanical products, motion of a part, which is functionally fundamental and sensitive to geometrical errors, is selected. A dynamic simulation method is developed, by which calculation of rigid body motion of a polyhedral object is possible. A motion path is generated by integrating the motion equations, along, which the contact state is dynamically changed. By giving simplified geometrical errors to the object's shape, estimation of the distortion of the motion path is possible. This leads to evaluation of the robustness of product design shapes.

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Excimer laser lithography is promising as next-generation semiconductor lithography because of its shorter wavelength of exposure light. However, due to the restriction of available optical materials, the projection lens which is specifically designed for narrow band excimer laser beam has much greater chromatic aberration against visible light. So, a TTL (Through The Lens) alignment system using visible light had a difficulty in applying to this type of projection lens. At this time, by means of introducing a compactly designed chromatic aberration correction lens, and optical heterodyne method, above-mentioned difficulty was removed. High accurate overlay accuracy of 3742nm ( x+3σ) was obtained on the developed excimer laser lithography system. Also this paper shows some discussions on the non-linearity feature of heterodyne interferometers.

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The aim of this research is to develop the air rotary bearing which has the following capability: (1) compensation of motion errors of the axis (high accuracy), (2) reduction of motion errors and residual vibrations which external disturbances cause (high stiffness and high vibration damping), (3) control of five degrees-of-freedom axis motion of the rotating axis (new function). To realize these, the authors have proposed an "Active Air Rotary Bearing" (AARB). In this report, a control system with PID-PD controllers is designed to control the five degrees-of-freedom axis motion. By using the control system, the AARB achieves; (1) 10nm positioning resolutions (x, y, z directions), 0.02arcsec positioning resolutions (φΨ directions), (2) almost infinite static stiffness and increased damping capability, (3) compensation of motion errors of the rotating axis.

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A teaching robot has been developed for the purpose of sophisticated teaching operations, such as to input technical skill of artist or artisan when machining industrial art objects. To realize easy operation, the teaching robot is constructed with a seven D.O.F. articulated mechanism and a two D.O.F. working table, in total has nine D.O.F. To improve teaching accuracy, error analysis and calibration for all geometric parameters are performed. As the results of experiments, an accuracy of 0.75mm(±3σ) by the teaching robot has been obtained. In this paper, error analysis of the teaching robot and geometric error model of it are discussed. Calibration algorithm and accuracy estimation are described also. Finally, an example of teaching and playback is shown.

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This paper presents the theoretical foundation of the two new techniques which correct the orientation of specimen surfacein area of5.6mm×5.6mm to measure three-dimensional rough surface. These techniques control the orientation of center plane such that roughness profiles situatewithin the measuring range by using profile data of small area. The basic process is to know the orientation of center plane by two center lines of roughness profiles. One of two named as the method I uses two measuring lines perpendicular to each other, and another named as the method II uses two parallel measuring lines. This paper gives the algorithm to get their optimum measuring lengths.

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For the profile measurement using software datum, it is not avoidable to suffer the error due to zero adjustment of multiple sensors. This error causes a parabolic error to the software datum line. Previously this zero adjustment is performed by measuring a given reference straightness. Theoretically the length of reference surface must he as long as the measured surface. This requirement makes the applications of software datum for the ultra-precision measurement narrow because the reference with sufficient accuracy can not be obtained. In this paper a new method is proposed to estimate the difference among zero points of multiple sensors by using only the data of profile measurement of the workpiece. This new method does not require any reference surface or any reversal measurement process. Experimental results with differential laser autocollimation method show that the reproducibility of the measurement of a mirror of 50 mm long was better than 30 nm which is equivalent to the highest accuracy expected from the thermal drift and the SN ratio of the sensor output.

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In the 1st part of this investigation, various shaped drills which have straight or circular cutting edges at the chisel edge portion and concave or convex cutting edges at the main cutting edge portion have been analyzed geometrically. Expressions for inclination angle and normal rake angle along the cutting edge have been obtained. In this paper, the experimental results on the cutting forces and chip formation such as chip flow angle and normal shear angle are shown and discussed on the basis of the results of geometrical analysis. It is possible to treat and explain qualitatively the cutting phenomena in drilling with various shaped drills under the given cutting conditions. It is found that the distribution of inclination angle along the cutting edge influences greatly on the formation of broken chips and the magnitude of thrust force, and Stabler's chip flow rule does not give the first approximate relation along the cutting edge when the main cutting edges of a drill are curved ones. Furthermore, as a result of the analysis and experiment, effective cutting edge configurations for the chip breaking and the reduction of thrust force are deduced.

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Finite amplitude chatter vi brat ion can be attributed to the non-linearities of cutting processes and machine tools. It was reported in the previous paper that shear localized chip formation during chatter vibration reduces the input energy from cutting system to the vibratory system to realize finite amplitude vibration. In this paper, finite amplitude chatter vibration is simulated in time domain using the dynamic cutting models developed previously. The vibratory system with 1 degree of freedom, which is vertical to cutting direction, is assumed. The non-linearity of damping coefficient to amplitude is also taken into account. The coefficient under certain amplitude is obtained by the balance of input and dessipation enegy of vibratory system. The amplitude of steady state chatter vibration simulated for various width of cut is in good agreement with experimental results. Vibrating cutting forces both of simulation and experiment have large power at higher order frequencies of basic diatter frequency. This is caused by non-linearity of dynamic cutting process.

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A method by which to transform quantities of an atomic model to those of a continuum one, and vice versa has been proposed. The method is based on an idea that the displacement at a point in a continuum model should be a weighted mean of those of surrounding atoms in the corresponding atomic model, while stress values should have the inverse relation so as to preserve strain energy between the two models. The continuum model is then discretized by the Finite-Element Method so that matrix equations for the transformation are derived. These equations have been applied to the results of atomic-model-based simulation of nanoscale cutting to evaluate the stress and strain distributions in nanoscale cutting. The results show that the strain distribution is not very different from that of macroscale cutting but that there is almost no concentrated shear stress in the primary shear zone in nanoscale cutting.

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NCプログラムに記述されている工具経路情報から,意味のある作業順序や工具移動パターンを分析し,作業工程を認識する手法を確立した.本研究ではこの部分に構文解析の手法を用いた.この手法を実際の生産現場で用いられている旋削用NCプログラムの作業工程認識に適用し,以下の結論を得た.
(1)作業工程の認識に構文解析の手法を用いることによって,認識問題の定式化が非常に明確に行えるようになった.
(2)実際の生産現場で用いられている旋削用NCプログラムから作業工程を認識し,非常に信頼性の高い認識結果を得た.
(3)NCプログラムから作業工程が認識できるようになったことで,NCプログラムに記述されている切削パラメータを抽出し,エキスパートシステムを利用して切削条件が診断できるようになった.

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This paper describes the influence of tool angles, especially rake angles, on the surface integrity of mirror cutting material. In this study, strain distribution in damaged layer is measured by a newly developed method. This method is applied electron beam lithography to drawing Au micro grids on the surface of oxygen free copper. Orthogonal cutting of specimen using various rake angle tools are carried out using a micro cutting device. It was found that strain distribution had close connection with tool geometry, and that highly compressed strain to vertical direction from machined surface was shown on the condition of negative rake angle tool. This method is effective to visualize cutting mechanism and material deformation at microscopic structure.

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This paper deals with a tribological study on the normal and the tangential forces which act on the thin metallic plate by ball rotating with thrust load forming. This forming can make metallic corrugated diaphragms under very small thrust loads without using blank holders. As the forming mechanism by means of the rotating is a dynamic behavior contained frictional phenomena, the tangential force is calculated by the adhesion theory, and the normal force is evaluated from the consideration of the combined stresses. The values of the theoretical study are in good agreement with the experimental results.

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陰極1つに対し,陽極を3つ有するアーク放電プラズマジェヅトCVD装置で電極位置を変化させてダイヤモンド合成を行い,ダイヤモンド合成に与える電極位置の影響について検討し,プラズマジェット径方向の放電距離の増加とともに,合成速度,合成面積および膜厚が増加することがわかった.しかし,中央部で厚く周辺部で薄いという膜形状にはほとんど変化を与えないことがわかった.

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