[in Japanese]

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[in Japanese]

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[in Japanese]

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This paper discusses the machinability of a self-fluxing alloy applied by thermal-spraying to machine parts based on observations of the cutting force and the finished surface. Cutting of this material is difficult using carbide tools, but possible with cubic boron nitride (CBN) tools. A large cutting force was applied to the tangential component of the three component forces. The surface roughness was fine, the roughness curve was stabilized, and a result approaching a theoretical value was obtained. However, microprotrusions of Ni particles, cleavage and plasticized flow were seen on the cut cross section. The best tools for cutting this self-fluxing alloy were CBN tools with high CBN content and the oxidized bonding agents.

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Thin diamond blade is widely used for the precision slicing of electronic parts such as magnetic head. It is well known experientially that some properties of blade have a great influence on the machining characteristics of workpiece, i.e. the work damage and the blade wear.ln order to understand the relation between the properties of blade and the machining characteristics, the mechanical properties of thin diamond blade are investigated in detail through the measurements of the tensile strength, the dynamic visco-elasticity and the wear resistance of bonding material. It is found from the experiments that there are notable differences in the mechanical properties of various blades.

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This paper presents the experimental investigation on the damping characteristics of turning tools. Especially, the effects of clamping load and surface topography are discussed. Both damping coefficients of normal and tangential vibrations to contacting surface at tool shank are controlled by the slip state at tool shank. When the clamp-ing load is low, a macro-slip between tool shank and tool holder occurs and large damping capacity is obtained. When the clamping load is high, a micro-slip occurs and damping capacity of the tool is reduced a little. Latter state of damping is important for real engineering operation. The explanation of these damping capacities is carried out from the point of surface contact with micro-asperities.

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In truing and dressing of a matrix-type diamond wheel with the GC cup-truer, bond material is found to remain behind cutting edges. This part of the bond material is called the bond-tail. This paper describes the mechanism of the bond-tail formation and a method of its characteri-zation, then discusses the effects on grinding performance. The main results obtained are as follows : (1) The bond-tail is formed in the direction of relative velocity between the truer and the wheel, which contacts with workpiece in grinding process when truing and grinding directions are different. (2) By truing with both sides of the truer alternately, the bond-tail can be controlled along with the grinding direction and the bond-tail angle grows with speed ratio of the wheel to the truer. (3) A large bond-tail creates a strong bonding force to hold the cutting edges, leads to large protrusion height in truing and prevents cutting edges from releasing in grinding. (4) An increase in cross-sectional area of bond-tail causes low density of cutting edge near the outer most surface of the wheel and low increasing rate in grinding force.

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Currently, when a designer thinks about the shape of an object to be manufactured by injection molding, he must consider the location of the objects parting lines. We have developed a technique which frees the designer of the need to consider parting lines, and thus design more aesthetically pleasing objects. After the object has been designed, the mold designer determines the points on the surface of the object at which normal vectors are perpendicular to the direction of movement of the mold. The parting line is then determined by interpolating these points. This technique allows parting surfaces to be finished with a clearance of less than 0.02 mm. The technique was developed after a thorough analysis of the relation between the ball endmill and the parting surfaces, the results of which suggest that current thinking in this area is only partially correct.

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The design verification is one of the most important problems in constructing an intelligent design support environment. Particularly in machine design, it is important to verify whether the designed machine can be assembled from discrete parts. This paper presents problem formalization for an automatic planning system which produces an assembling sequence of a given machine structure which is described in the design object modeler CONMOTO. The 'sequence is equivalent to the constructive verification whether the designed machine can be assembled. At first several restrictions are introduced and the assembling procedure is inverted to a disassembling procedure. Discretizing the direction and the dis-tance of the part's movement by some heuristics, the disassembling procedure can be acquired by the search-based problem solving method which is so called in the artificial intelligence research field. Finally this paper shows the disassem-bling sequence can be planned efficiently utilizing a “Plan Tree” which is heuristic partial order of assembling. The detail of the planning system is shown in the next report.

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In the continuous path (CP) controlling robots such as welding, painting, sealing and bonding robots, the circular arc interpolation is usually adopted to the rounding of the sharp edges of corners. However, by the discontinuity of curvature at the points connecting lines and arcs, it tends to cause vibration at the points. For the purpose, the authors developed a new method of corner interpola-tion which uses Clothoid curve. The curve has a continuously changing curvature which is proportional to the length of the curve. This report describes the basic theory and the computing method of the curve and gives the practical data for Clothoidal interpolation.

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This paper describes an expert system for selecting the optimium cutting conditions, which enables us to arrive at the conditions in a similar way to the practice in actual machine-shops. The way of thinking of expert tool engineers for obtaining the optimum cutting conditions was first examined through a questionary investigation. The system was then constructed so as to possess the same functions as those in their way of thinking. The most important functions of the system are the prediction and the resolution of machining troubles such as chatter vibration, excessive tool wear and rough surface finish. Two different approaches are taken depending upon the kind of the troubles, which are retrieving data method with aid of the evaluating functions and analytical method through the algorithm of the metal cutting theories. As an example of the latter method, a sub-system for evaluating tool wear is developed together with a filling up method of its data base. This system is also proved to work well by experiments.

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Point-in-Polygon Tests are basic geometric algorithms in solid modeling. The 4 × 4 Determinant Method provides a structured framework for all interference problems in the modeling process. The authors have proposed two different algorithms for Point-in-Polygon Tests based on the 4 × 4 Determinant Method, the PNZ Triangle Method and the Vertex Convexity Method. This paper compares the (1) algorithm simplicity, (2) arithmetic operations per vertex, (3) pre-calculable data, (4) accuracy in floating point arithmetic, (5) applicability in special cases, and (6) applicability in faces with curved edges, of the two algorithms. This shows which algorithm is preferable in each situation, and which algorithm is suitable for implementation in a hardware geometric processor.

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For the optical measurement of the object shape, several methods such as moire method or one point measuring method are generally employed. However, the former takes considerable time to process, and the latter gives only the position of one point. For the object with simple form, there are cases that its position and posture are simultaneously necessary. This paper proposes a measuring method using digital image processing, that is applied for above cases and is available to measure both position and posture in a short time. In this method, an X-pattern is projected to an object and the deformed X-pattern is observed from another direction. The position and posture are obtained by analyzing the deformed pattern. As an experimental result, the position measuring accuracy of 0.2 mm is achieved, when the object's moving range is 100 mm and the distance between the origin and the camera is about 1 m. The angle measuring accuracy is 0.2 degree, when the object's rotation range is 50 degree. The time required for one point measuring is about 1 second. The method is applicable to measure the position, the angle, the shape of floor and so on.

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A new-type friction and wear test appratus is developed which features dynamic controllability of the load by incorporating an electro-magnetic servomechanism in loading system. In the apparatus one pin specimen is impressed on one roller specimen by means of electromagnets. The currents to the magnets are regulated to make the load follow a specified command signal whose values are determined according to the rotational angle of the roller specimen. The I-PD control system is adopted for obtaining desired characteristics of load control. It is confirmed experimentally that the apparatus can perform a repetitive friction and wear test under various dynamical load conditions.

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In this paper, about planar multilink path generators consisting of revolute pairs, describing links and radial clearances at revolute pairs by vectors, the analysis of output errors at the generated points is carried out. Moreover, describing link lengths and diameters of holes and shafts by random variables, the optimum tolerances of link lengths and pairing elements are determined as tolerances that make the output errors minimum and uniform at the generated points over the full ranges of input motions. As a practical example of planar multilink path generators, the optimum tolerances of link lengths and pairing elements of the planar six-link path generator are determined.

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The stripe pattern projection system is analyzed theoretically and experimentally in order to improve detection precision in automatic focusing which is included in the visual inspection equipments used for semiconductor. The design guide for the best system is also described. In the theoretical analysis, the mask defocus, the size of illumination source, the pupil diameter, the wafer defocus and the wavelength for illumination are considered. The contrast variations of projected patterns are calculated in case that the wafer is assumed to have a diffusing or mirror surface. In the experiment using wafers in production, the detected contrast exists between the ones calculated in the afore mentioned two surfaces. The theoretical values coincide with the experimental ones qualitatively. By this suitable design, it is possible to obtain 0.3 μm precision in automatic focusing.

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A measuring method for determining the sharpness or cutting edge radius for a diamond tool has been proposed and reviewed, to contribute to the advancement of ultra-precision diamond machining technology. In this research, a sectional curve of the cutting edge was figured out by processing image signals from a remodeled SEM with two secondary electron detectors. The research showed that a parabola was closer to the calculated result of the SEM signals, when the apex of the sectional curve, created by the SEM image signals, was approximated by a circle and a parabola. In addition, the cutting edge radius could be given in numerics based on a conic section displayed by a parameter using a simplex method. The measurement error analysis also revealed that the measurement error, according to the electron beam diameter, was almost negligible. The diamond edge shape was not altered by the Au film thickness, which is normally used to avoid an electrical charge before measurement. The cutting edge radius could be measured accurately. The cutting edge radius values for diamond tools thus measured were in the 20 to 45 nm range.

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This paper deals with the command of temperature control of machine tools. Customarily the fixed value control of the spindle head's temperature has been adopted for the machine tools found specially in the fixed room temperature. And follow-up controls to the room temperature and to the machine temperature have been widely used for the machine tools in the conventional machine shop. However the theoretical analysis has not been conducted concerning the command temperature. Computer simulations and cost-performance analysis have been conducted, and the following results are obtained : (1) For high quality machine tools in the conventional machine shop the tempera- tures of the spindle head and of the bed should be follow-up con-trolled to the room temperature. (2) For economical machine tools the follow-up control of the spindle head temperature to the machine temperature is very effective.

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This paper deals with the simulations of the torsional vibrations of gear driving axis, and the synthesis of vibration wave forms theoretically, by using transfer function method. The transfer function is measured between the two points, one of them is the point on which the applied force is generated by gear tooth contact, and the other is the point at which the torsional vibration of the axis is measured. Another important parameter is the applied force generated at gear contact point. The frequency spectrum of the vibration wave forms are obtained as the results of the products of the transfer function and the frequency spectrum of the applied force, and then vibration wave forms are obtained by inverse FFT of this spectrum. The results of the simulation shows that the synthesized vibration wave forms and their frequency spectra are in good agreement with the results of experiments.

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This paper deals with experimental considerations on the method of axial tension control in elastic region which was proposed by the authors et al. Characteristic points of the method are summarized as follows : (1) the value of compliance in the axial direction of a bolted joint is utilized to be the basic parameter instead of the torque coefficient, (2) the control is performed by basing on a final fastening torque predicted in a fastening process. A fastening apparatus constructed consists of a DC servo-motor and a single board micro-computer, having functions of sensing the fastening torque and the axial tension and cotrolling the ends of fastening. From the experimental results on accuracy and response in the method, it comes out that the method brings higher accuracy in the axial tension control than the calibrated wrench method widely known and used at present. In addition, it is suggested that the method becomes available by performing a preliminary test to gain an exact value of the compliance.

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