[in Japanese]

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[in Japanese]

View full abstract

[in Japanese]

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[in Japanese]

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In order to fabricate three-dimensional profiles with high accuracy, on-the-machine measurement is required. A method for on-the-machine measurement by calibration with spheres used for references has been developed. In this paper, an arm with passive joints for on-the-machine measurement is proposed. As a prototype of the arm has 4-DOF (degrees of freedom) including 2 passive joints, the probing system totally has 7-DOF including DOF of the machine tool. The angle of the passive joints is changed by driving the NC table and the main axis of the machine tool where the arm is mounted. In order to calculate the optimal posture of the arm for the shape to be measured, a numerically analyzing method of the inverse kinematics is also proposed. The prototype of the arm has enough positioning accuracy to calibrate its posture. Shapes can be automatically measured with the accuracy of micrometers order by the on-the-machine measurement method.

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The acquisition of profile data and the production of CAD models are key elements in the style design based on a master model. So the present studies aim to generate high-quality CAD models from high-density measured point data on a master model having character areas. This report deals with a new method to measure such a master model and a fitting method to generate free-form surfaces onto the high-density measured point data. A master model is measured with a non-contact 3-D digitizing system. A non-uniform cubic B-spline curve fits onto the measured point data on a measurement line. A non-uniform knot vector is obtained in the “equivalent curvature area dividing method.” Coons patches of C² continuity are generated from the fitted B-spline curve as a boundary curve of patches. Twist vectors are calculated in the Adini method which utilizes adjacent patches. In the experiments, a high-accuracy CAD model fitted onto the measured point data on a master model. To get a high-quality CAD model, patches should be small in the character areas, so a new method is also proposed to extract character areas in the high-density measuring method.

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For the sake of bin-picking, usually three-dimensional recognition is applied. However, this method uses complex recognition procedure that needs much computing time, and the probability of successful recognition is not sufficiently high. In our research, first the position of the part having maximum height is detected using coded lattice pattern, and then two-dimensional recognition is made in the neighborhood of the highest point. By this way the minimum necessary data for bin-picking are obtained. The active slit pattern is used only for detecting the highest location instead of obtaining three-dimensional image in the conventional method. The lattice slits are coded by changing the combination of the thickness of lines. By using this visual method together with the versatile vacuum chuck, We obtained successful result of electrolysis capacitors bin-picking.

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In coordinate metrology, an associated feature (Gaussian associated feature) is normally calculated from an extracted feature which is determined by a measured data set of CMM (Coordinate Measuring Machine) using a least squares method. This data processing flow which is called as “feature based metrology” disagrees with the data processing methods in profile metrology and length measurement. The most significant difference between feature based metrology and profile metrology is quantity of a number of measured points on each measured feature. In feature based metrology, the number of measured points is very small and a data sampling strategy is a discrete sampling. On the other hand, a continuous sampling strategy to measure many continuous points is adapted to profile metrology. In this paper, the basic concept of feature based metrology is discussed in defining a feature model, calculating parameters of feature and estimating uncertainty of measurement. Three-dimensional modeling for threedimensional feature, least squares method and statistical estimation strategy for estimating the uncertainty of the feature agree with feature based metrology. The series of simulations for the feature based metrology in statistical way directly implies that the basic concept and the basic data processing method in this paper are useful to feature based metrology.

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In the end of World War II, Japanese industry of rolling bearings had disappeared because of bombing of the U.S.Air Force. In 1990's, about 30% of rolling bearings in the world are manufacturing by Japanese multinational bearing companies. The paper made clear the reasons why the acceptance of Japanese bearings to the world market after World War II. The reasons were the formation of production principles in Japanese manufacturers which depended deeply on Japanese people's national mentality came from their traditional sensitivity and perfectibility for artifacts. The production principles were to make low noise and vibration bearings, and long durability bearing. The paper deals with the processes, of technological progress of the bearings according to the principles, production technology and reliability assurance technology.

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This paper proposes a new method for the construction of the topological structure for the output solid of a Boolean set operation on polyhedral solids. The method constructs the face loops of the output solid based on the topological connectivity of the vertices and edge-face intersection points and their clusters represented symbolically by means of face names. In order to prevent accumulation of numerical errors, the degeneracies such as edge-crossing or coincidence between vertices, edges and faces of input solids, which are detected during the process, are transformed into topological constraints on the output solid.

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This paper describes a system to acquire experienced process engineer's thought model automatically that is necessary for knowledge based computer aided process planning system in job shop type productions. The system is developed for flexibly deciding the condition and facility used in the process according to a difference of production culture. For the system, it is necessary to acquire the thought model based on information processing model of a human brain because culture depends on a human way of thinking strongly. Thought model, however, has been acquired by interview up to now. The proposed system automatically determines thought model in the case of operation planning. A good result is obtained experimentally to show the system is useful to distinguish the thought model of the difference of production culture.

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Although it is still difficult to clarify the relation between cutting quality and the cutting conditions with influencing of complexities of its cutting mechanism, laser cutting has been recognized to be an indispensable technology in the recent untraditional machining. This paper deals with methodology to optimize cutting conditions such as laser power, gas pressure and cutting velocity for CO₂ laser cutting of steel. This methodology has five stages. Firstly, experiments are carried out to collect data of surface characteristics produced under the various conditions. Secondly, using experimental data, multiple regression models of surface characteristics are constructed. Also, profit rate of CO₂ laser cutting is formulated. Thirdly, evaluation functions are determined as to fuzzy membership function. Fourthly, optimum cutting condition based on the fuzzy mathematical programing is deduced. Finally, the satisfactory cutting condition obtained by this methodology is verified experimentally.

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This paper describes the geometrical surface modification of a synthetic silica glass. Varying the incident angle, the fluence and the number of pulses, ArF excimer laser beam was irradiated on to a synthetic silica glass. As the incident angle increased, striae parallel to the radiation direction appeared. Particularly when the angle was larger than 80°, the striae lined up in the direction of radiation. However when the angle larger than 83°, no striae could be found on the surface. As the results, incident angle extremely effects the lining up. Threshold fluence to form striae was 4J/cm². From the observation by AFM, the length, the depth and the width of a stria were 15mm, 130nm, 1.5mm, respectively. Moreover to examine the formation mechanism soda-lime glass, quartz, corundum and calcium fluoride were chosen from the viewpoint of crystal structure or low absorption ratio of 193nm light, and they were irradiated on the same way. Only on the quartz similar striae appeared. These results draw the conclusion that the low absorptkon ratio and SiO₂ composition easily form fine striae.

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Stainless steel pipe with fine hole and long size has recently been needed for the flow line of pure gas and liquid, which is used in the field of precision machinery. Inner wall polishing of the capillary is very difficult by ordinary finishing methods. In the present study, new polishing method has been developed, in which polishing is performed by flowing slurry at high velocity through the capillary. The developed machine has been proved to have excellent polishing performance. Experiments show that the surface roughness of as-received stainless steel capillary is reduced from 0.7 μ mRa to about 0.1 μ mRa within several tens of slurry passes. The roughness of finished surfaces decreases with increase in abrasive grain concentration, and with increase in grain size. Optical and scanning electron micrographs of the polished surface indicate that texture pattern of the inner wall disappears in early stage of low pass number. N₂ gas flow pressure measurement can be applicable for an estimation of the finishing level.

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This paper describes the prediction of the fracture area and fracture probability in failure of a cemented carbide end-mill under side cutting and side-end cutting operation by the method introduced in previous paper.The prediction method by FEM computer simulation is applied to several cutting conditions mainly using the two-flute end-mills with helix angle 30°. The main results obtained are as follows : (1) It is theoretically predicted that the failure of an end-mill originates at the cutter sweep and the fixed end independently of cutting condition. (2) Only by modifying of applied cutting load, the calculation result approximately agrees with the experimental result. (3) Only by calculation, influence of the depth of cut, feed, cutting position, the position of cutter sweep and helix angle, on the fracture probability and failure position, is investigated. (4) A four-flute end-mill is safer than a two-flute end-mill under the same cutting condition.

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This paper deals with FEM and experimental investigations of the deformation of precision airspidle in diametrical expansion and axial contraction due to the centrifugal force during spindle rotation. The deformation of spindle rotor is measured with special experimental setup and the results are compared with the FEM analysis. Special precautions are taken in the experiments to realize precision measurement of the order of one-hundredth micro-meter, such as compensation of the thermal deformation of spindle, protection of the sensor probes against exhaust air flow from the air bearing and low-pass filtering of the displacement output. The experiments are carried out in a speed range up to 7200 rpm, and it is clarified that the measured results agree well with the calculation.

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The machinability of reinforced sintered high speed steel, which mainly consists of SKH57 with a little TiN, V, Co, has been clarified. Two type of it were machined with several kinds of conventional newly developed tools, and fundamental machining data such as tool life, cutting temperature, cutting force and surface finish were obtained. The main results obtained were as follows : (1) The cutting temperature of reinforced sintered high speed steel were about twice as high as S45C. Especially, over 100m/min, its temperature is more than 800°C. (2) Negative rake angle is available. (3) Specific cutting force of it is as well as S45C steel. (4) Ceramic tool showed excellent cutting performance under every cutting conditions and long tool life.

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WC with different sintering density ratio has been sintered without binder by spark sintering process. High-quality diamond film, which has higher nucleation density and smaller crystals compared to that on WC-Co, has been deposited on this WC substrate by micro-wave enhanced plasma CVD method. The result of a comparison study convinces that the adhesion strength of diamond films on this cobaltless sintered WC is remarkably superior to that on WC-Co, which is believed to be improved as a result of the increasing diamond nucleation density, the enhanced bond between the substrate and the diamond film, and the improved match of thermal expansion coefficients caused by the absence of the fatal obstacle of cobalt. Moreover, the indentation test has been proved that lower sintering density of this sintered WC may result in an increased adhesion strength.

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Carbon nitride films have been prepared by ion-beam-assisted deposition, in which carbon was evaporated by electron beam and nitrogen and/or argon ions were simultaneously bombarded onto silicon substrate. The influences of the argon ion addition on the surface roughness, the nano-indentation hardness and the friction coefficient of carbon nitride films are investigated. Furthermore, the composition and the chemical bonding states of carbon nitride films are analyzed by Rutherford backscattering spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. Even in the films prepared at the ion beam gas ratio (Ar/N₂) of 1, argon concentration was about 2at% although around 30at% nitrogen was incorporated. Nano-indentation studies show that argon ion addition in the film formation process below 100°C lead to the higher hardness of the film and that the maximum hardness was 23GPa. Furthermore, argon ion addition was effective for reducing the friction coefficients of the film against a steel ball. Nls peaks in XPS spectra indicate that population of nitrogen surrounded by three carbon in the C-N network, which corresponds to C-N cluster formation, increased by argon ion addition. Therefore, the improvements of the mechanical properties of the films are thought to be induced by the C-N cluster formation promoted by argon ion addition at low temperature.

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Many researchers have selected a favorable anisotropic etchants from the viewpoint of its anisotropy, safety, selectivity, and conformity to LSI production process, however, guideline for selecting favorable anisotropic etchants is not yet established. The present paper has established a guideline for selecting a favorable anisotropic etchant from the experimental results with finished profiles under water-dissolved CsOH etchant, and proposed two-step etching process which consists of the first etching under water-dissolved KOH etchant and the second etching under water-dissolved CsOH etchant.

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A new machining method was developed to produce micro-scale shapes for optical devices. This method containes a high-speed rotating microblade and high-speed fine particles that are accelerated by the rotating blade. With this method it is possible to obtain a smooth and undamaged surface at the same time that the micro-shape is machined. The fine particles allow a rather large amount of material to be machined very near the blade. They also enhanced cutting where the blade contacts the material. This method was applied to make an in-line optical micro-filter and a hemispherical end fiber. These devices performed well with an insertion loss of 0.21 dB for the microfilter and a coupling loss of 2-3 dB for the hemispherical end fiber.

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