[in Japanese]

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The purpose of this study is to improve a productivity of a manufacturing of graphite. Generally, in case of the high speed process, several chippings arise on the surface and the edge of graphite. Phenomenon of the chipping hasn't been known well. Therefore, the manufacturing is processed with a low speed. This study is to grasp a phenomenon of the chipping and an influence of the cutting condition. A style of a destruction mechanism is a crack type. There are normal cutting surface and many craters. The authors confirmed that these craters were deeper than the cutting surface. The width of edge chipping increases in proportion to the feed rate. However, it is not related to the radial depth of cut and the cutting speed. It is related to the 3-dimensional cutting force and the rigidity of the work edge. Most distinctive point is that the width of chipping is related to the cutting force on tooth face. The authors thought that it can be controlled by an angle of helical endmill, so the authors developed the left twisted endmill, which has high helical angle. It can decrease about 70% of the width of edge chipping.

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This paper describes a mechanism of deep hole drilling of covalent bond-ceramics using a pulsed YAG laser. The deep hole drilling process was simulated by the newly developed analysis method. It was combined the ray tracing method for a laser power intensity distribution analysis and difference method for a thermal analysis. It assumed that laser beam energy was delivered by reflection from the internal wall surface of a hole in the ray tracing model. Sublimation process of silicon nitride was considered during the thermal analysis. The deep drilling hole was processed mainly by energy reflected from the internal wall surface of the hole. In this process laser power intensity became higher in the center of the hole since the laser beam was focused by the wall-reflecting effect.

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Accuracy improvement of the models created by three dimensional photofabrication depends on the conditions whether or not a machine uses the proper photopolymer and selects laser power and scanning speed to minimize the depth variation which is caused by the laser power's and the scanning speed's stabilities. The experimental equation between exposure condition and solidified shape enables the quantitative comparison of photopolymers. Several experiments show that the solidified depth is expressed by four parameter coefficients, laser power and scanning speed. This paper discusses the comparison method of solidified depth stability using this relation.

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This paper proposes a method to generate an offset surface between a tool and an object which is covered with free form surfaces. Crosscorrelation function is used to calculate the offset surface. For calculating the discrete crosscorrelation function, the tool shape and the free surface object are represented by Voxel representation method, which usually includes quantization errors. Intermediate values are given to the cells at the surfaces of the tool and the object to reduce the quantization errors. This offset calculation method is used for machining a free form surface object that is a die for Boubure anomaly distribution map model.

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High speed machining of Inconel 718 with SiC whisker reinforced alumina, silicon nitride and TiC added alumina ceramic tools was carried out. All the ceramic tools tested showed the maximal value of the notch wear around the cutting speed of 100 m/min. SiC whisker and silicon nitride ceramic tools showed good performance compared to TiC added alumina ceramic tool in respect of the notch wear under the low cutting speed or low feed rate. However, over the cutting speed of 400 m/min, not only the notch wear but also the flank wear of these tool became large, while TiC added ceramic tools showed the smallest wear compared to other tools. Notch wear of these tools can be suppressed by pouring the cutting fluid at the depth of cut line.

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In order to investigate the grinding actions of the pored type diamond wheel with vitrified bond, the tangential grinding force was theoretically analysed in connecting with the constant-load grinding of Zr0₂-Y₂0₃. The influences of structure of wheel to the force were numerically presented by the three loading rates which directly relate to the constituent ratios of diamond abrasive grain, filler grain and bond. The force is deeply referred to the ploughing action of tiny tips on the ground surface. Filler grains in wheel decrease the cutting action of diamond abrasive grains and increase the frictional action between abrasive grains and workpiece. The calculated values of force are large on the grinding of Zr0₂-Y₂0₃ sintercd at higher temperature. The smallest values of force are on the grinding of Zr0₂-Y₂0₃ doped 3 mol% Y₂0₃, but the calculated values abruptly increase for the grinding of Zr0₂ doped 4 and 6 mol% Y₂0₃ due to their small plastic yield pressures.

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The present study proposes a computer simulation method which can be employed to predict cutting forces, chip formation, cutting temperature and tool wear in a real three-dimensional turning process with a continuous chip. The finite element formulation using a linear tetrahedral element has been implemented. The overconstraint problem emerged from using the element has been solved by extending the Nagtegaal-Rice functional either to a hexahedron which consists of six tetrahedra or to a pentahedron which includes three tetrahedra. The effects of elasticity, plasticity, temperature, strain rate, large strain, friction and tool wear are all included in the formulation. The three-dimensional simulation has predicted the effects of cutting action by the front and side cutting edges upon the cutting mechanism, such as the development of plastic deformation in the finished surface followed by the increase in temperature and severe wear near the edges.

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This paper describes the effect of the magnetic field distribution on the removal distribution of the workpiece surface in the magnetic field-assisted polishing method. In case of applying this method to the curved (aspheric) surface polishing, the next process is suitable. The designed shapes are first generated precisely by turning or grinding, and then the surfaces are finished only to improve the smoothness, with the previous form accuracy being maintained. Therefore, in order to carry out the uniform removal polishing using the magnetic field-assisted polishing, it is important to clarify the processing mechanism of this polishing method. In this report the relation between the distribution of magnetic field and the polishing pressure distribution was analyzed theoretically and experimentally using several shapes of magnetic poles in the polishing set-up. And, by polishing examination of the flat glass, the relations between the magnetic field distribution, polishing pressure distribution and polishing removal distribution were analyzed experimentally. As a result, the relations between the magnetic field distribution, polishing pressure distribution and polishing removal distribution were clarified.

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In the underwater explosive forming, in which pressure is controlled by changing the distance from an explosion source, there are two subjects that have to be solved for controlling the extent of forming of blank sheets. One of them is the pressure or energy of an explosion source, and another is the determination of the attenuation coefficient that represents the attenuation of pressure waves due to distance. I f these values can be determined, the force and the energy acting on a blank sheet can bedetennined, consequently, the forecast and the control of the extent of forming become easy. The characteristic values of an explosion source are calculated with the simple estimation formulas which are expressed by the functions of only the initial density of its explosive.Moreover, the attenuation of pressure waves due to the distance from an explosion source to a blank sheet is determined with the empirical formula. Further, the pressure in the vicinity of an explosion source, of which the direct measurement is difficult, is estimated with this empirical formula.

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This paper describes a process to machine tip radius of diamond stylus as surface roughness measurement using ion sputter. The ion sputter machining produces a similar shape as the original stylus. It also controls the parameter using the current density, machining time, incidence angle of the ion beam. As the result, a stylus of any tip radius can be machined as requested. In this paper, the ion beam process is used to produce a diamond stylus with a radius of 2 μm and angle of 90°. The optimal machining condition is resulted with a radius of less than 0.5 μm. With this result, efficiency of machining reaches to 93%.

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In this paper, the scanning force microscope (SFM) using optical heterodyne interferometry is reported. The birefringent double-focus lens was used as a beam splitter-recombiner, and thus, the two interfering beams passed through a common optical path and the reference plane of the interferometer was located on the sample surface. Therefore, the deflection of the cantilever was detected without being affected by the irregular movement of the stage and the environmental conditions, such as thermal and vibrational disturbances. Since the SFM system was combined with a laser interferometric microscope and a conventional optical microscope, the sample was positioned easily by the visual inspection, and it was measured by the laser interferometry.

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It is important to eliminate the non linear spring characteristics for positioning accuracy as like as the mechanical hysteresis characteristics. So that, the characteristics has to be analyzed to improve the dynamic performaces. At first, the “Non Linear Spring Test Unit” is developed, which consists of two linear spring characteristics parts and mass. The magnitude of Non linearity is defined which evaluates the influences on these dynamics. Then these in fluences are tested using this unit, it is proved that the non linear spring characteristics make worse on positioning accuracy at the mechanical resonance frequency, and the allowable non-linear spring magnitude can be quantified as like as the mechanical hysteresis characteristics.

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A small SCARA robot for planar continuous path control has been developed. To realize high-speed and high-precision continuous path control, the robot was carefully designed by considering path planning, motion design, mechanism design, control system design, and teaching method design. The absolute accuracy performed by the robot is ± 0.4mm in the standard working area (about A4 paper size), and the maximum speed of 500mm/s is obtained under reasonable accuracy. The accuracy is regarded as small as one tenth (1/10) of that performed by the conventional CP robots. The design policy is described and the experimental results are reported in this paper.

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This paper presents the new technique to measure the surface roughness profiles correcting an orientation of specimen surface in one operation. The contact stylus profilometer is equipped with the table whose inclination is controlled by the computer. The positioning of the stylus tip in the vertical direction is corrected at the same time. For assuring to measure profiles in length of 5.6mm, the surface profile data for control is demanded to be obtained in the length of 1mm. This measuring length varies depending on form errors such as the waviness. Then this paper gives the new technique to correspond the above-mentioned problem.

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In order to suppress vibration due to unbalance of rotating spindles, many kinds of automatic balancing apparatus have been developed so far. However, they cannot work sufficiently at a high rotational speed because of incorrect actions of such mechanisms in a rotating unit of the apparatus as a compensating mass movement mechanism, power supply mechanism, etc. Most of the incorrect actions are caused by complexity of the mechanisms. In this research, a balancing apparatus composed of highly simplified mechanisms has been newly developed by utilizing ultrasonic motors which can rotate at a very low speed without any reducer and stall withoutany brake. In the rotating unit of the developed apparatus, two ultrasonic motors on a rotor of which a compensating mass is stuck, printed circuit boards and rechargeable batteries as a power source are equipped. The unit is installed on the objective rotating spindle so that the motor axes may be aligned with the spindle axis and the motors are driven through infrared PCM signal from the stationary unit. Software suitable to control the hardware has been also developed by adopting the steepest gradient method.

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This paper presents consistent transformation processing from pixel coordinates to dimensional coordinates, which plays an important role in the final stage of the whole recognition method for mechanical drawings. The output data of the both bottom-up and top-down processing are represented in pixel coordinates, which have inevitable quantization errors. So, they should be transformed into coordinates in terms of dimensions that give consistent geometric constraints to all drawing elements. The authors have realized to solve this problem by developing a unique method called 'dimension-matching, ' making use of the structural model and automatically generating simultaneous linear equations with respect to internal dimensions for outlines. The way of implementing this processing is described and some examples are finally shown.

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This paper presents a generation method for curves which have smoothly varying curvature to satisfy designer's intention under the condition of tangent direction and curvature values at arbitrary points on the curve. This method determines curvature variation directly by an evolute as a rational 2nd degree Bézier curve, then approximates its involute by rational 3rd degree Bézier curves. The generated curves have G² continuity at the connected points and compose NURBS.

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