[in Japanese]

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Although a considerable number of studies have been made on the trouble shooting based on simple rules to control the manufacturing systems, little attention has been given to the point of trouble handling based on the higher strategy level. The purpose of this paper is to propose a new system, a strategy-based trouble handling system, that consists of a filter module, the trouble prediction system, and the trouble handling proposal system. First the filter module calculates several characteristic quantities with sensing data concerned with each trouble, then distinguishes them into three levels (L, M, H) by comparing the calculated quantities with standard ones. The trouble prediction system, which is constructed of association mode of the neural network algorithm, converts output of each level through the filter module into figure patterns. The system predicts the corresponding troubles from the figure patterns even if they are vague. The trouble handling proposal system suggests the handling instruction considering the situation of the whole system, which is used through the back propagation of the neural network algorithm. The evaluation tests were carried out in a NC drill machine. The results showed that the developed system could judge the troubles clearly and suggest handling instruction as exactly as mature engineers did.

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When we generate the cutter path for free-form surfaces by a CAM system, we have to minimize the aircut of it and to ensure the accuracy of the machined products. But it is very difficult for the conventional CAM system to set the adequate cutting condition and to generate the path only for the part to be cut. On the other hand, a profiling machine has been commonly used by die-manufacturers, because it enables the workers to directly generate the cutter path during monitoring the cutting situation. However a profiling machine needs the master-model of product and the accuracy of the cutter path is not high. Therefore we introduce the virtual reality into NC programming system for free-form surfaces. And an accurate virtual profiling system without master-models was realized. The worker can manually profile the model in the computer and can generate NC data for free-form surfaces by using the proposed system. In this paper, the construction of the virtual profiling system is described. The virtual profiling system consists of a bilateral master-slave system which has a 3DOF orthogonal direct drive manipulator, a profiling simulation software, and a cutting simulation software. The virtual profiling system can generate the cutter path for free-form surface models in real time with the accuracy of ±0.1μm.

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Surface modelling systems are indispensable tools for designing aesthetic shapes of mechanical products. Contemporary CAD systems provide modelling functions for generating and modifying free form surfaces. They can also perform surface evaluation by rendering surfaces or drawing characteristic curves, such as iso-parametric curves, contour curves, highlight curves. The aim of this research is to propose a new and intuitive surface modification method based on those characteristic curves. With this method, designers can modify surfaces by directly manipulating those characteristic curves. The formalization of the problem is simple, but results in an inverse problem. This problem is solved by applying the standard regularization theory. A computer program is developed to numerically evaluate the method and applied to several examples. It is demonstrated that the method can be used as a basic surface modelling capability.

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This study deals with the method of collision avoidance in the automatic tool path generation for 5-axis control machining. The 5-axis control machining offers the potential of efficient and accurate machining, while the collision between a tool and surrounding objects is still a severe problem. The method devised in this study realizes the judgement on the possibility of collision avoidance at the position where the collision take place, and produces the direction of collision avoidance, based on the 2-dimensional configuration space defined by two parameters which determines the tool posture. This method allows a test workpiece with an overhanging part to be actually milled without collision. As a result, the validity of the method is experimentally confirmed.

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A new type of externally pressurized infinite stiffness gas bearing is proposed. This bearing is constructed with a movable bush, a spring plate and two restrictors in series. The configuration of the bearing, working principle and the analysis of the static characteristics are presented in the previous paper. This paper describes the construction of a circular thrust bearing and experimental results of the static characteristics. Experimental results show a good agreement with the analytical values and it is proved that the bearing has infinite stiffness.

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In order to determine the energy flowing rate into a workpiece in surface grinding, the temperature in workpiece was measured by the thermocouple insertion method, in which the fine constantan wire was inserted and welded in the small hole, and the temperature around the hole was numerically analyzed using 3-dimensional heat transfer equation by control volume method. Through the analysis the effects of temperature measuring methods, such as size of fine hole and existence of constantan wire, on the measured temperature were discussed in detail. The temperature around the bottom of the hole, measured point, becomes 2 or 3 times higher than that without hole, especially at near the ground surface. The energy flowing rate into workpiece was estimated using the results by 3-dimensional temperature analysis and the measured temperature with the thermocouple insertion method. The estimated ratio is 30-40% of the total grinding energy and the rate is about a half one which is obtained based on 2-dimensional analysis.

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This paper describes some experiments for breaking a silicon wafer precisely using YAG laser. The popular mechanical cutting of a silicon wafer using a diamond blade is not always high quality. The noncontact cutting of ceramics using CO₂ laser is recently being studied enthusiastically. The precise breaking of a silicon wafer, however, has never been achieved. In the experiments, the conditions and the quality of double irradiation breaking are searched in various atmospheres. It is found that air cooling, water cooling and assist gas method has similar breaking forms. Main crack meanders and it is accompanied with some branching cracks which deteriorate the breaking quality of a silicon wafer. However, local cooling method enabled high quality breaking. The measurement results of the surface roughness of cross section are extremely small, 0.003-0.004 μm at Ra. It is also shown that the crack propagation velocity of local cooling breaking is about 10m/s higher than that of other ones.

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In order to optimize accuracy and efficiency the grinding process, the grinding results of every possible combination of grinding conditions should be predicted and evaluated prior to actual grinding. Many kinds of grinding models and databases have been proposed for this, with one of the simplest and most popular being the database which uses the classical regression model. To enhance the flexibility of this type of database it is important that the data which is utilized for prediction and evaluation be that which has been collected through field testing. However there are many cases in which mne data is not rich enough for estimating the regression coefficients. The learning and prediction method which this paper proposes is applicable in cases where the amount of learning data is not sufficient for re-estimating the parameters of the regression model. In addition to the classical regression model this method utilizes the fuzzy linear model. The performance of learning and prediction algorithms are evaluated by computer simulation and case study.

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This paper describes a chatter vibration control and a recognition of cutting state in boring operation. A vibration control system consists of piezoelectric sensors, piezoelectric actuators and a controller. The signals of the tool vibration are detected by the piezoelectric sensors and modified into the rectangular waves which are applied to the piezoelectric actuators to drive the tip of a boring tool. A cutting state recognition system which is based on an artificial neural network is also proposed. In this system, power spectrums of the signals detected by piezoelectric sensors are calculated to identify the cutting state. The input data of the artificial neural network are normalized by the maximum value of the power spectrum. The normalized patterns are utilized to identify whether the cutting state is stable or unstable. The vibration control system and the cutting state recognition system have been examined in cutting tests. The test results verify the effectiveness of the proposed systems for practical application.

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A new method of producing stainless steel fibers by shaving coiled sheet has been developed. To prevent the fibers from sticking to each other, hot water soluble resin coated coil is used. This coating decreases fiber sticking from 40% to 8%, thus enabling uniform and fine fibers to be produced. It was also found that thinner fibers can be obtained when thin sheets are used than when the feed rate is decreased. As a result, fibers with equivalent diameters of 14 μm were obtained with metal sheet of 10 μm thickness and feed rate of 5 μm/rev. The tool life until re-grinding was about 40 minutes and productivity was about 15 kg/h, confirming that industrial production is possible.

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This study deals with the technology of the high speed end milling of hardened steel by the milling machine with an air spindle. Lately, high speed milling machines with ball bearing type spindle have been developed, and several tests related to the high speed or high efficient milling of hardened steel have been tried. But, there are a number of unclarified points regarding to the cutting mechanism of the high speed milling. This paper therefore tries to clarify the cutting mechanism and aims to present basic data on practical use for the high speed end milling of hardened steel. The main results are as follows; (1) The dynamic characteristics of the air spindle are obtained by experiments. (2) The stability diagrams are obtained by experiments based on the surface roughness and observation with the eye of machined surface. (3) In case of unstable conditions, selfexcited and forced chatter occur. The later generates because of the excitation by the cutting force of intermittent machining. (4) It is shown that the stability range of machining by 2-flute end mill becomes larger than that by 6-flute end mill, because the frequency of intermittent machining by 2-flute is smaller than the natural frequency of the air spindle.

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The influence of cutting speed, and thermal properties of the work material and the tool material on the thermal partition coefficient is investigated theoretically and experimentally. The temperature at the top of a conical tool is measured immediately after micro chip forming using an infrared radiation pyrometer with an optical fiber. A carbon steel, a titanium, a molybdenum and a tungsten are used as work materials, and a silicon nitride Si₃N₄, a zirconia ZrO₂ and a diamond are used as tool materials. The cutting temperature increases in proportion to the 1/2 power of cutting speed and saturates to the melting point of work material. The fraction of heat conducted into the cutting tool is independent on the cutting speed, and it becomes larger as the thermal conductivity of workpiece is smaller or that of tool material is larger. In the diamond tool which has the highest thermal conductivity, its thermal partition coefficient is the highest, but the tool tip temperature is the lowest.

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In coordinate metrology, when a certain geometrical relation between features is specified due to functional requirements, it is sometimes necessary to evaluate them as a lump. Such evaluation method, however, has not been well developed. In this paper, therefore, a lump of features is defined as a composite feature and its concept is described. In addition, an evaluation method of a composite feature has been proposed. It is based on fitting in position and orientation between a composite feature model and measured data sets, which are obtained by the measurement of a part using coordinate measuring machines. Two-plane and two-cylinder composite features have been given and formulated as concrete examples of a composite feature. Computer experiments have also been performed in both examples and validity of the method has been confirmed. Proposed method is easy to be extended to any other cases.

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A three-dimensional (3D) single-stage positioning system that magnifies input displacement has been developed. The 3D positioning single-stage is supported with four linkages that include rotational pairs of flexure hinge, and these elements are all consist in one united body. The stage is driven with piezoelectric actuators of which displacements are magnified by the actions of levers. The magnification rate and interference have been theoretically analyzed by matrix structural analytic method and the optimum structure has been designed. In the 3D single-stage positioning system developed, displacement of 40-50 μm has been occurred with magnification rate of about 3 times as large as each of input displacement.

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Present studies concerning with the field of the industrial robot off-line programming system have not yet established an effective method to correct the mechanical errors that exist between the geometric model of a robot and the actual robot itself. In the correcting method of mechanical errors of a robot, there is no report to correct non-geometric errors, such as a robot arm deflection error, gear backlash error, and so on. To correct both geometric and non-geometric errors, three dimensional measuring instruments and strict accuracy management in the measuring devices are needed. The estimation and correcting method with the instruments is not suitable for the usage in an actual manufacturing system such as a practical processing goods line. In the first report, it was pointed out that all the mechanical errors in this study could be expressed by the linear model which was treated with both geometric and non-geometric errors. In this report, the estimation and correcting method with the linear model are proposed for the application of the practical industrial robot. Moreover, the proposed correcting system is evaluated.

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When optical stylus sensors are used to measure edged profiles or surfaces with scratches, overshooting phenomena occur sometimes. In the present paper, the overshooting on edged profiles is analyzed in views of reflection and diffraction by an optical ray tracing method. In the ray tracing, reflected beams from all of the three surfaces (upper, lower and side surfaces) of the edge are taken into consideration. In the view of diffraction, the focal point is considered as a beam waist with a diameter derived from Gaussian distribution. The simulation shows that the height of the overshooting has a close relation with the focus error and the height of the edge. It is also shown that the overshooting occurs even though the optical system is perfectly adjusted and it is also demonstrated that the ray reflected from the side surface is one of the main causes of overshooting and the beam waist is another cause of overshooting. Finally, the results of simulation are compared with those of the experiment using a critical angle prism sensor.

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This paper presents an optical apparatus for measuring small hole diameter. The apparatus, basing on the principle of geometrical optics, enables to measure diameters of through holes with high aspect ratios. The measuring range is 0.1-1mm. Four light beams made up by concyclic four pinholes incident onto hole wall with a large incident angles and their reflected beams form four images on a charge coupled device. From optical relations and picture processings about the images, the value of the diameter is obtained. Being employed ferrules of the optical fiber connecter, etc., as test specimens, some problems about measuring conditions and data processings are experimentally examined and solved. According to actual measurements, the measuring accuracy is estimated to be 2.3 μm(standard deviation) and, under a special condition, 1.4 μm(standard deviation). It is also found that the apparatus can measure specimens without mirror surfaces well.

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This paper describes a new scanning probe microscope which is able to measure the shearing stress generated by the interaction between the STM tip and the sample surface under STM controlled. The method of measurement is utilized the quartz crystal microbalance technique. The sample is deposited on the AT-cut quartz crystal resonator surface, and the shearing stress which is generated in the sample causes the resonance frequency shift of the quartz crystal resonator. By detecting this signal, we can obtain the shearing stress distribution. The gold thin films have been observed for the STM surface topography and the distribution of subsurface shearing stress simultaneously. In the experiment, the sensitivity of the shearing stress is as high as 0.12 N/m for a 0.05 Hz frequency shift of the quartz crystal resonance frequency.

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