The operational rate of automatic production lines is determined by the trouble rate, the recovery time and the capacity of intermediate buffer under sufficient loading of works to handle. Works are loaded to the line through a loading buffer which is prepared with the top of the line and the number of works must be loaded enough to keep the operational rate of the line. In this paper, simulations for production lines with a loading buffer are performed. In the simulation, the loading to the loading buffer is performed with almost equal intervals of the cycle and the loading buffer is filled by works at loading. The relation of the loading frequency to the buffer capacity, which is not affected for the operational rate of lines by the loading, is shown by the results. The main results are as follows : (1) as the buffer is filled in works at loading, it is necessary that loading for the buffer is performed more than three times while the line handles all numbers of works in the loading buffer, (2) the minimum loading frequency for sufficient loading is given by the presented equation, (3) in calculations of the equation, it is suitable that P_IN is 0.95 for operational ratios of over 10% and 0.975 for other cases.

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Rational curves such as rational Bézier curves and NURBS are widely being used in CAD and CAGD, and defining them as homogeneous curves in homogeneous space has many advantages in geometric processing. In this paper, some properties of quadratic rational Bézier curves and NURBS defined in homogeneous space are discussed. First, the relationship between the two kinds of homogeneous curves is studied. Secondly, the implicit form of quadratic homogeneous Bézier curves is derived, and by using the implicit form, the inclusion test and the conic classification (hyperbola, parabola, and ellipse) are performed. Finally, the fact that a whole conic can be represented as one homogenized NURBS is shown. The properties discussed here are more general than those of conventional rational curves.

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This paper presents a new method of designing a product in consideration of its quality, or solving the design-for-quality problem of the product, with decornpositional approach, assuming that the product is decomposed into plural parts in parallel. At the stage of product design, product quality is evaluated with Taguchi's quality loss function, which can be regarded as a measure of the generalized quality cost of the product, and its expected value is often estimated through statistically designed experiments. The proposed method derives the solution of the design-for-quality problem from performing plural small groups of experiments, which are concerned with each part of the product respectively, instead of conducting a huge group of experiments about the whole of the product, so that the scale, complexity and difficulty of the experiments are reduced. Further, the effectiveness of the method is investigated through an example.

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多面体の干渉計算において, 稜線と面の交点を3面の面名からなるシンボルで表現し, そのシンボルの接続関係から交線ループを作成する方法を提案した.またそのアルゴリズムを実装し, ごく薄い角度で交わる2つの立方体の干渉計算において, 頂点一面一致トレランスと内外判定トレランスをさまざまに変えて数値実験を行った.その結果, 従来は計算できなかった非常に微妙な交差の場合にも, 本アルゴリズムによって自動的に交線ループが作成できることを確認した.
本報では扱わなかった面一面一致などにより交線ループが閉じないケースの扱い, および集合演算 (和・差・積) の結果の立体を生成する処理に関しては, 第2報で報告する.

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This paper proposes a method for detecting visual pixel defects on color liquid crystal displays using an image processing system. The types of pixel defects of liquid crystal displays are bright dots which are always lighted and dark dots which are always extinguished. Bright dots are detected by a local image binarization method using distribution of brightness on a display. Thresholds for binarization process are set by each pixel using a linear complementary method. Dark dots are detected by the local image binarization method after multiple one-dimensional image differential operations. A relationship between brightness and a conspicuous ratio is evaluated about bright dots for transforming the original measured brightness into the value which is related with a conspicuous ratio. Detectable ratio for bright dots reached to 96.2%, and for dark dots reached to 93.8% by the developed inspection system and methods.

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Diamond has excellent physical and chemical properties. So diamond was applied to some industrial products. But natural dia-mond and high pressure and high temperature synthesized diamond have limited to their application by their forms and sizes. Though diamond particles and films can be obtained using CVD methods, there are many problems such as low adhesion strength to use as tools and mechanical parts. In this paper, Diamond growth state using microwave plasma CVD and adhesion strength between diamond film and WC-Co substrate were studied. Cutting test of A1-18mass%Si (A390-T6) alloys using diamond coated tool was carried out. As a result, low temperature growth was recognized on the scratched after Co removal WC-Co substrates. On the cutting test, using the tool which coated diamond at high temperature (about 1173K) after Co removal and scratch pre-treatment, cutting length was less than 200m and crater wear was severe. Using the tools which coated diamond at low temperatures (from 680K to 779K) after Co removal and scratch pretreatment, following increase of substrate temperature, cutting length became being long and crater wear became being mild. Compared with the tool which coated diamond at high temperature after Co removal and scratch pretreatment, the tools which coated diamond at low temperature after same pre-treatment improved cutting performance. Especially the tool which coated diamond at 779K performed more than ten times longer life than the tool which coated at high temperature after same pre-treatment. When suitable pre-treatment and growth conditions of basic factors on diamond synthesis were selected, diamond coated tools which have good cutting performance could be made.

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This paper presents the fabrication process and transformation characteristics of reversible shape memory alloy thin film actuators which are useful for micromachines. Nickel (Ni) -rich titanium-nickel (TiNi) alloy thin films were sputter-deposited on a rock salt plate or copper foils and heat processed with two steps which are the crystallization (800°C-10 min) and the shape memorization (400°C-6 hours). Reversible shape memory effects of the actuators were shown between the room temprature (R phase) and high temperature (about 90°C) (austenite phase) by electric current heating. Their metallurgical properties were analyzed by ICP, DSC, XRD and TEM. It was found that precipitates of Ti₃Ni₄ played important roles as bias springs for the shape memory effect as same as the bulk TiNi alloy. Consequently, the relations between the fabrication process and transformation characteristics of the actuators which were useful to realize reversible shape memory alloy thin film actuators for micromachines were obtained.

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Zerodur glass-ceramics has been ground into a ductile mode by a 5-axis control ultraprecision grinding machine with bronze-bonded diamond wheels which have been dressed by grinding a sintered SiC plate. Zerodur glass-ceramics of extremely low thermal expansion coefficient is one of the best material to keep precision in any high technology field, though the grindability of Zerodur in a ductile mode is not good due to low fracture toughness. Various dressing methods have been tested with SD2000J150M and SD40001150M grinding wheels. The ductile mode grinding can be obtained on Zerodur samples with the dressed SD4000J150M wheel by grinding a sintered SiC plate after the removal mass of 34 mm³/mm at a unit width of wheel in order to arrange the height of cutting edges of diamond wheel. The surface roughness of 13nm rms was obtained by this grinding.

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This paper evaluates the impact of a jet supplied cutting fluid in the turning of an Inconel 718 workpiece which has low machinability. A water jet system was used to supply the cutting fluid to the cutting point at pressures ranging up to 68.6 MPa, 10 times higher than the maximum range of conventional commercial high pressure systems. In 68.6 MPa jet supply cutting, the friction coefficient on the flank and rake faces were 4%-35% less than in wet cutting, and the cutting temperature decreased by 45%. Use of the jet supplied coolant led to reductions in flank wear, which increased the tool life by factor of three. Both the coefficient of friction and the tool wear tended to decrease as the pressure of the jet supply increased.

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To improve shift feeling is required for automobile transmission parts. For this purpose, it is important to increase an accuracy of involute spline. That is to make profile modifications for a pair of teeth in mesh and to improve roughness as well. Although a technique to use honing is effective for the above requirements, it has not been sufficiently studied. A new tooth finishing experiment with CBN abrasive wheel for the involute internal spline is made. It is clear that the best tooth accuracy can be obtained by the slant traverse feeding, reducing a speed ratio between revolutions and feed. Maximum finishing roughness is improved approximately by half to compare with that of before honing, until now. With a speed ratio of ψ=1, roughness is obtained at 4.8 μmRz in tooth profile direction and at 0.8 μmRz in tooth lead direction. At a revolution load torque of 3 N·m and a machining time of 20 seconds, chips are smoothly exhausted and honing is effective. In conclusion, it is now clear why the proper tooth accuracy and roughness can be obtained.

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This paper experimentally deals with a rolling behavior of a steel roller on a steel rail. Hysteresis loops which are formed in transient region from stationary state of the roller to continuous rolling state are described, varying diameter of the roller, roughness of the rail and pre- load. By measuring an area and a slant of the hysteresis loop, it is found that these factors affect not only characteristics of the rolling friction in continuous rolling state but also characteristics of the rolling friction in transient state. Furthermore the relation between the transient and the continuous rolling states is written by unified functions of nondimensional parameters.

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Recently, the role of skilled operators in manufacturing systems is recognized again and the utilization of the mentality and flexibility of human operators to them is focused on with fresh interest. In order to apply the manual operation to a manufacturing system effectively, it is important to investigate the skill learning characteristics of the operators and derive a reasonable skill training method for them. The virtual reality techniques appear to be very useful to carry out this investigation, though the actual manufacturing system is not necessarily suitable for it. In the present paper, the objective manual operation is small-diameter deep-hole machining of an aluminum workpiece with a bench-mounted drilling machine, which is known as a difficult operation requiring operator's sensitivity highly. Firstly, a simple simulator of the drilling machine or a virtual machine has been developed taking into consideration the dynamic characteristics of a real machine. Secondly, its effectiveness to the skill training has been studied through experimental operations by inexperienced testees. A new index for assessing operating performance was also discussed. As the results, it is found that the developed simulator is significantly effective in skill training for the actual drilling machine operation and the operating efficiency continues to improve during early 15 time operations with the simulator.

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This paper describes the development of an ultra-high speed grinding (UHSG) machine which is capable of 400m/s wheel speed. UHSG is one of the high efficiency machining methods. It has reached the stage where it can complete well with respects to machining efficiency even in comparison with a cutting method. Concept of the UHSG is not new, however a practical application of the UHSG was difficult due to the manufacturing problems of a grinding wheel and a wheel spindle unit in the ultra-high speed rotation. In the previous work, an ultra-high speed spindle unit (30000 rpm, 22kW, 2×10⁶ dn-value) was developed. In this paper, a UHSG machine using the spindle unit was designed and manufactured. Vibration, noise and coolant friction loss of the machine were measured and compared with the conventional grinding results. The UHSG tests were performed under the 300m/s wheel speed using the developed machine and a vitrified bonded CBN wheel. The CBN wheel having a CFRP core was specially designed. However, coolant supply was not enough in the region of the UHSG, therefore the development of a low friction supplying method is needed.

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Chip formation process using chip breaker is analyzed by implicit-type elastic-plastic FEM (Finite Element Method). By simulating the transition process of carbon steel (S 45 C) cutting, it is found that the cutting process varies when the chip contacts with the workpiece. That is, the chip thickness near the rake face increases, and the cutting force on the rake face decreases, while total cutting force increases. The cutting simulation results including chip shape and the total cutting force are compared with in-situ scanning electron microscope observation of cutting process, and they are in good agreement. The chip formation process is also simulated with changing chip breaker distance. In this simulation, it has been calculated that as the chip breaker distance increases, the chip curl radius increases, and an amount of the increase in the total cutting force decreases.

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In order to improve the simulation system and develop the control system with high performance, the dynamical model of the controlled object must precisely be derived. Ordinarily, the parameters are estimated by using the characteristic point data on Bode diagram. As is well-known, this method is widely used in the production field. Meanwhile, the co-quad diagram based parameter estimation method was also known. It has been said that this method can derive more precise modal parameters than the conventional method can. However, an explanation for the theoretical background is insufficient. In this paper, this reason clarified by introducing the sensitivity function. Firstly the frequency response curve both of Bode diagram and co-quad diagram are shown for the compliance, the mobility, and the inertance. Next the parameter estimation formulas are derived by using co-quard diagram. Secondly, by introducing the sensitivity function, it is shown that the co-quad based method has better performance from the parameter estimation point of view than the conventional one has. Finally, the parameter estimation method based on co-quad diagram is applied to the measured inertance response and it is confirmed that the realistic parameters can derive in comparison with these from Bode diagram.

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This paper deals with a new evaluation method of conically ground drill point geometry, aiming to develop a computer aided inspection system of it. In the proposed method. five geometrical parameters for the evaluation are derived from the kinematic relationship between the drill point and the grinding wheel when regrinding. The parameters are determined by mathematical model matching with the measured coordinates of many points on the flank surface. Various matching methods such as gradient methods and Genetic Algorithm are examined by numerical simulation. The results show that the combined method of Steepest Gradient Method and Genetic Algorithm is suitable for this matching from the viewpoints of calculation speed and accuracy.

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The high power laser welding is performed with very complicated physical phenomena. These physical phenomena should be visualized using several quantitative measurement methods to get a highly reliable welding process. In this experiment, plasma cloud was investigated using a high speed camera and a measuring device to get a plasma voltage. A moltenpool and keyhole was visualized by CCD camera while irradiating N₂ laser on the surface. It was found that plasma size was constant even if welding speed changed at both He and Ar gas atmosphere within this experimental condition. Keyhole diameter on the surface was changed from approximately 1 mm to 1.5 mm while varing welding speed and power. Absorption ratio of stainless steel SUS 304 on keyhole welding, also was measured by calorimetric method by measuring the temperature rise of copper block in which SUS 304 test piece was press-fitted. It was found that the absorption ratio shows an almost constant value of 0.7-0.8 even if input energy (J) has been varied.

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This paper introduces a new method to measure tooth profile error of minute module gears. In this method, regarding the surface of a gear as a sort of surface roughness, the optical cutting method is applied. Because the tooth depth of the gear here aimed to measure is very low, this method can be expected to be applied availably. To ensure the ability of this method, a measuring apparatus which employs a CCD camera as an observing device was constructed. The optical cutting image of the tooth observed by the CCD camera is led to a computer and the tooth profile is presented with a fine line image processing. By comparing it with a calculated ideal profile, the tooth profile error can be obtained. Measurements for a gear with the module of 0.2 are carried out successfully, in which a resolution is estimated to be about 1.1 μm in Y direction and 1.6 μm in X direction and standard deviations of repeatedly measured values are about 3 μm. Besides, some factors generating measurement errors are pointed out and discussed for developing this method better. As a consequence it becomes clear that the method has a good ability to measure total profile error of minute module gears.

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