Generally, a job shop consists of work-centers in which alternative machines with different processing efficiencies exist. This paper presents a machine selection rule used to select a machine to process an operation from the alternative machines in a work-center. For dynamic scheduling, the proposed rule takes into consideration not only minimizing the current workload of the bottleneck machine but also minimizing the total workload. Machine selection methods by delaying decision until a machine becomes idle are also examined and compared with the proposed rule. Numerical experiments show that the proposed rule is simple but effective and robust.

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Product configuration optimization at early design stages requires the simultaneous evaluation of numerous design aspects. However, the existence of complex relationships among design alternatives, such as subordinate and constraint relationships, increases the difficulty of formulating the problem model and conducting straightforward searches for optimal solutions. This study presents a method for representing design alternatives having such relationships that uses hierarchical genotypes to enhance the design optimization efficiency of genetic algorithms. Furthermore, the efficiency of different genotype structures is compared using numerical experiments. Based on the experimental results, a procedure for constructing optimal hierarchical genotypes is proposed. The proposed methods are then applied to a robot arm design optimization problem to illustrate their effectiveness.

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In this paper, the bristle model proposed by C.Canudas et.al. for frictional characteristics of sliding bearings is applied for linear ball guideways. A method for determining unknown 6 parameters of this model has been proposed. The simulated results using the bristle model agreed with the experimental results about the following three kinds of characteristics : the nonlinear spring behavior curve (static characteristic), frequency response and step response (dynamic characteristics). Therefore, the bristle model can estimate the frictional behavior of the linear ball guideways.

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This paper proposes a new Neural Network composite control to achieve good control performance in terms of both velocity and position in a hydraulic servo motor system with inherent non-linearity. This control system is equipped with two state feedback Neural Network compensators that are independently designed from a velocity and position compensator. The input signal sent to the hydraulic servo system is generated by selecting the output of two compensators in accordance with the driving condition of the hydraulic motor. This report firstly describes conducting a simulation and experiment with the condition that the angular velocity and position were constants. It secondly confirmed that Neural Network composite control is necessary in order to attain better velocity and position control performance. In addition, selection of the compensator output was studied, revealing that composite control was most effectively performed through smoothed selecting of the signal using a sigmoid function. Furthermore, experimental verification indicates that the Neural Network composite control has exceptional control accuracy and robustness.

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An efficient algorithm for binary template matching is proposed. For efficient search, object images to be checked is divided into two regions: R-region and P-region. In R-region, an upper limit of correlation coefficients can be derived as an interval estimation based on mathematical analysis of correlations of the object image and a pivot image. In P-region, another interval estimation is formalized based on the number of white and black pixels in a template and the object image. By use of these interval estimations, a scanning-type upper limit estimation of correlation coefficients can be formalized for the efficient search algorithm. Experiments show the effectiveness and efficiency of the proposed search algorithm.

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This paper aims to propose a fast image searching method from environmental observation images even in the presence of scale changes. A new scheme has been proposed for extracting feature areas based on a robust image registration algorithm called Orientation code matching. Extracted areas are stored as template images and utilized in image searching. As the number of template images grows, the searching cost becomes a serious problem. Additionally, changes of viewing positions cause scale change of an image and matching failure. In our scheme, richness in features is important for feature area generation and the entropy is used to evaluate the variety of edge directions which are stable to scale change of the image. This characteristic contributes to limitation of searching area and reduction in calculation costs. Scaling factors are estimated by orientation code density which means the percentage of effective codes in fixed size areas. An estimated scaling factor is applied to matching a scale of template images to one of observation images. Some experiments are performed in order to compare computation time and verify effectiveness of estimated scaling factor using real scenes.

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In this study, a new method is proposed to suppress a hardness-decrease in a ground surface of a hardened carbon steel with a grinding process, by the nitriding caused with a solid phase reaction in N₂ gas grinding process. Modified nitriding in a halogen lamp rapid heating furnace and grinding test show following results: (1)Grinding method using N₂ gas supplied throw out wheel has a possibility to suppress the hardness-decrease of the ground surface of a hardened carbon steel. (2) The thickness of the nitrified layer obtained by the grinding in N₂ gas is thinner than that obtained by a common method. (3) The grinding in N₂ gas with a coolant is also useful to accelerate the suppress hardness-decrease in grinding process.

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This paper describes the elucidation about influence of dilute NaCl electrolyzed water on surface character of nickel material. First, the immersing experiment was conducted which is immerse industrial pure nickel material of 99.3mass%Ni and plating side of nickel into the electrolyzed reduced water and electrolyzed oxidized water of dilute NaCl. Next, weight, externals, and the surface shape of the samples to which immersing experiment was done were confirmed. Furthermore, the surface of the samples of 99.3mass%Ni industrial pure nickel material that after immersing was done was analyzed by Auger electron spectroscopy, and the change in the chemical composition and the change of the oxide film thickness etc. were clarified. As results of the study, following could be identified. (1) Dilute NaCl electrolysis water can be applied to the machining of the nickel material and the process of the surface treatment etc. before and after plating. (2) Electrolyzed reduced water doesn't give the influence to the surface of nickel material at all. Therefore, use as the cutting fluid is possible. (3) Electrolyzed oxidized water has the action that improves the etching action, the smoothing action, and the nickel purity for the surface of nickel material, and it doesn't discolor to the surface of nickel material. Therefore, electrolyzed oxidized water can be applied to oxide film removal processing line before plating.

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Possibilities of fatigue failure and self-loosening of bolted joints increase if the clamping force would be reduced. Therefore, controlling clamping force and preventing clamping force loss are always required in service.
Two methods for preventing decrease in clamping force on bolted joint have been developed in this study. Two types of wedge are used to prevent the self-loosening in these methods. One type of the wedges is a tapered plate and another type is a conical wedge. These wedges are inserted to either a tapered groove or a conical hole which has been made in a bolt tip after a bolted joint was tightened. The vibration tests have been practiced to confirm usefulness of these methods. And then, the tensile tests and FEM analysis of bolted joints have also been achieved to check the strength of bolted joints.
It has been verified that these methods are useful for prevention of self-loosening on bolted joints. However the proposed methods have decreased the tensile strength of bolted joints due to providing internal groove or hole in a bolt. FEM analysis has revealed that the proposed method make the principal stresses at the roots of the threads except for the first thread of bolt and the bottom of conical hole increase.

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This study deals with the optimization of grinding operation with super abrasive diamond wheels. In this paper, the developed equipment extracts the vibration sound of the wheel using the microphone. And, the discrimination of the quality of wheel conditioning, truing finished and of dressing interval is discussed based on signals obtained from vibration sound of diamond wheel. As a result, it is clarified to identify whether truing and dressing operations are completed or not, by detecting the sound pressure level at the specific frequency of the wheel. And, the sound pressure level at the specific frequency of the wheel can replace the evaluation for the cutting quality of the wheel.

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In the wafer polishing process, the polishing removal rate decreases with the increase of the polishing time. In order to investigate this behavior, polishing pads have been analyzed through microscopic topography, and by means of creep deformation, friction coefficient, and sludge accumulation. The creep deformation was observed in the surface layer of a polishing pad when a cyclic force equivalent to the polishing pressure was loaded. Based on the cyclic loading test, the elastic deformation decreases gradually with the increase of the polishing time after passing a wafer on a polishing pad. This creep behavior resulted to the decrease of the supply of slurry, which is the most important factor of the polishing removal rate. Thus the decreasing behavior of removal rate is verified to correlate strongly with the creep behavior of the polishing pad.

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The present paper deals with Photo-CVD combining both monosilane(SiH₄) and ozone(O₃) under atmospheric pressure. The purpose of this study is to prepare silicon dioxide (SiO₂) thin films, which have high transparency and a high deposition rate, without thermal and chemical damage to the substrate. In this paper, characteristics of the SiO₂ thin films are experimentally investigated. This paper will conclude that Photo-CVD using ozone as opposed to pure oxygen can improve the deposition rate of SiO₂ thin films to 37.6nm/min under the comparatively lower substrate temperature of 147°C. An added benefit is the improvement of the optical and physical property of SiO₂ thin films. And the most important parameter to increase the deposition rate is the concentration of ozone. Therefore, further improvement of the deposition rate may be possible by using higher density ozone.

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We notified that Cu concentration on the Si substrate surface could be reduced to less than 2.4×10⁹atoms/cm² by the cleaning method using high-speed shear flow of ultrapure water. But the mechanism of Cu removal in this cleaning method was not clarified. In this study, we have attempted the clarification of Cu removal mechanism by the observation and analysis of the Si substrate surface after the cleaning using high-speed shear flow of ultrapure water and SPM (sulfuric acid-hydrogen peroxide mixture) cleaning. In consequence, we showed that a lot of bosses were not observed on the Si substrate surface contaminated by Cu after the cleaning using high-speed shear flow of ultrapure water though after SPM cleaning. And we supposed the reasons about removing Cu from Si substrate and not forming a lot of bosses on the Si substrate surface by Pourbaix diagram for Cu-H₂O system.

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An objective of this study is to develop a new method for the prediction and the avoidance of chatter vibration in milling operation by using 3D-CAD and CAE approach. Also, a new identification method for the modal parameters of vibration system by analyzing radiated sound pressure from vibrated workpiece accelerated by impulse force is proposed. Then chatter stability lobes are predicted using those modal parameters. Stiffness and modal shapes of the workpiece were obtained using commercial finite element method (FEM) code, and the model was made by 3D-CAD. The damping ratio, which cannot be determined through FEM analysis, was identified from the relationship between the sound pressure radiated from the workpiece and the impulse force. Chatter stability limit was analyzed with the modal parameters obtained through these procedures, and compared with the cutting experiment on the chatter stability limit. The experimental and predicted stability limits are in good agreement when the axial depth of cut is comparatively small. The proposed procedure will help to set the cutting conditions to avoid the chatter.

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Sintered tungsten carbide is machined in ductile mode by applying “elliptical vibration cutting”, and the mechanics of the ductile mode cutting are investigated in the present research. Grooving experiments of the sintered tungsten carbide are carried out at low vibration frequency so that the vibration cutting process can be monitored easily. The groove machined by the elliptical vibration cutting is smooth without any visible fractures, while those machined by the conventional linear vibration cutting and the ordinary cutting are rough with numerous micro fractures. It is considered that the difference is caused by reduction of thickness of workpiece material cut in each cycle of the elliptical vibration. The same difference is confirmed at ultrasonic frequency, and it is also clarified that high quality surfaces are obtained when the vertical amplitude of the elliptical vibration is lower than 0.5 μm_0-p, which corresponds to grain size of the sintered tungsten carbide. Based on these fundamental results, the ultrasonic elliptical vibration cutting is applied to ultraprecision planing of the sintered tungsten carbide, and ultraprecision machining with surface roughness of less than 50 nm Rz is realized, although the tool life is relatively short.

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