For a micro-hole machining using punching system, always the uniform clearance between a punch with a die hole must be precisely aligned. Thus, on-line monitoring of tool position is considered to be important. In the present study, the effect of uneven clearance due to misalignment of the positions of the punch and die on shape of cross-section, diameter of hole and out of roundness are investigated in phosphor bronze as workpiece material. Then, a on-line monitoring procedure of tool misalignment using machining force was proposed, and the method was verified through experiments.

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We have developed the piezoelectric actuator having a single stator with translational and rotational motions (TR Motor). The stator has been fabricated as a rectangular metallic solid with a through-hole. The inner surface of the hole generates vibration modes, transferring the energy to a shaft, when voltages at each resonant frequency are applied. In this paper, the performances of the TR motor are clarified toward the practical use. The performance was measured after optimal preload was determined. As the result, the maximum torque and rotational speed were approximately 2.5 mNm and about 120 min^-1, and the thrust force and translational speed were approximately 0.33 N and about 85 mm/s. In addition, the motor characteristics by the amplitude, frequency, and phase difference of the applied voltages were measured.

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To be attained a high precision groove machining of nano-sheets with Atomic Force Microscope (AFM), it is necessary to make clear the groove machining mechanism by analytical method. This paper proposes the theoretical formula which takes aim at the groove generation energy of groove machining on nano-sheets. Construction of this formula thinks of stochastic process because edge chippings of a machined groove is suggested brittle mode machining. Besides, the groove generation energy of unit edge length is corresponded to groove width. Accordingly, the existing probabilistic of machined groove width is assumed Boltzmann distribution. The edge chipping generation probability calculated from this formula is tended to be consistent with the evaluation value of groove machined. Furthermore, optimal machining condition of scanning speed is estimated to be around 70 ∼ 140 nm/s.

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On the basis of the fact that the main cause of the formation of a deformed layer remaining on a machined surface is the extension of the shear zone to below the intended depth of cut, the relationships between the plastic flow remaining on the machined surface and the cutting parameters are analyzed using a simplified cutting model and confirmed experimentally by low-cutting-speed orthogonal cutting tests on 60-40 brass and aluminum. The following results were obtained. We found that the plastic flow is approximately proportional to the product of the shear strain of the chip and the depth of cut. The proportional coefficient is the ratio of the shear strain in the deformed layer to the shear strain of the chip. Furthermore, the plastic flow is approximately proportional to the chip thickness and to the main cutting force per unit cutting width. In addition, the specific cutting force is approximately proportional to the shear strain of the chip.

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The present study presents a practical system to predict tool wear considering cutting conditions and workpiece components. The proposed system is developed for automation of production processes, optimization of cutting conditions, development of new workpiece materials, etc. The system consists of tool temperature analysis and tool wear prediction. The tool temperature is simulated by FEM analysis, and then the tool wear is predicted by utilizing the simulated temperature. The tool wear prediction model has a few constants which need to be identified for each set of tool and workpiece materials. The constants are identified and the material properties are measured for steel workpiece and a carbide tool, and the system is verified by some experiments in the present research.

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Bearing steel (JIS: SUJ2) heat treated to hardness value above 58 HRC has been overwhelmingly used for rolling bearings, ball bushes, and ball splines with rounded shape rolling machine elements. It is thought that for this material when the fatigue test is carried out in the domain of high cycle fatigue of the S-N curve- the so-called Wöhler curve, a fatigue limit appears. This type of fatigue limit has been used in the ISO standard since the year 2000 within life modification factor a_XYZ or a_SL or a_ISO for rolling bearings. However, at present even in the life test of bearing or S-N fatigue test of material, the experimental data does not show any apparent sign of the fatigue limit. In this research work, alternating torsion fatigue test for probabilistic stress life (P-S-N) evaluation is carried out under standard stress values, from τ=1 GPa to τ=0.5 GPa for 6 lots made up of a total of 150 samples, and P-S-N curves were determined based on the three-parameter Weibull distribution and lognormal distribution. Based on the result, it is reported that the bearing steel does not show any fatigue limit.

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In injection molding, surface defects such as weld-line and silver streaks are serious problems which trouble engineers. It is also known that these surface defects can be prevented by heating the mold cavity surface to above the resin melting point Tm or glass transition point Tg. In this study, we designed and made a rapid heating and cooling mold applying induction heating, which is capable of continuously heating and cooling the cavity surface rapidly. This mold has a cavity insert with coils and cooling channels arranged inside the mold base. Using the mold, heating and cooling molding and normal molding without performing heating and cooling were performed and effects on the external view and surface properties of rapidly heated and cooled molded products were investigated. Observation of the surface of the product molded using this mold showed that in normal molding, the formation of V-shaped weld-lines is seen on the molded product surface. On the other hand, when heating and cooling is performed in molding, no weld-lines are found, and compared to normal molding, a highly glossy molded product surface has been confirmed.

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In this study, a clinometer which automatically measures the angular positioning deviations of a tilting axis is developed. Multi-axis machine tools consist of translational axes and rotary axes. The positioning accuracy of translational axes is checked by the laser interferometer. Although, there is no proper measuring instrument to measure the angular deviations of the tilting axis whose center line is lower than the top surface of table. Thus, a clinometer consisting of rotary encoder, pendulum with electronic level and servo motor was developed. The developed servo-clinometer mounted on the tilting rotary table moves around the tilting axis, and the pendulum moves by the servo motor so that the output of electronic level becomes 0 degrees. Through the experiment, it is confirmed that the developed method is enough to measure the angular deviations. The developed devise could be applied to the horizontal plane, however it was not able to measure inclined plane such as multi tasking lathes with a milling spindle.

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In order to inspect our hypothesis that stress concentration is closely related to the cause of dental caries, the finite element structural analyses of tooth and periodontium were carried out. The possibility of the correlation of stress concentration and wedge-shaped defect, periodontopathy and eminence of alveolar bone became clear. Then, contact problem analysis of adjoining teeth or upper and lower teeth were carried out. It became clear that the origin of dental caries is a stress concentration zone. This stress concentration point is similar to actual growth point of caries. Furthermore, it was clarified that there was a correlation of stress concentration and attrition, fissure-pit caries and secondary dentine.

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In designing a holder part of a large stamping die, designers must consider not only the functional property of the holder, but also its manufacturability. The holder part is produced by cutting and engraving table, wall, slot and pocket features into the raw cast shape. Raw cast shape has inevitable large shape errors. It often has 5 to 10mm shape difference from the CAD model prepared in the designing phase. This shape difference causes some unmanufacturable features which is difficult to detect with a CAD model of the nominal shape. In this paper, the authors propose a new manufacturability verification system which can detect such unmanufacturable features caused by the shape errors. Proposed system computes a geometric model of the holder part with shape errors by modifying the CAD model. Inverted offsetting and cutting simulation are successively applied to the model to extract the unmanufacturable features. An experimental system is implemented and some computational experiments are performed.

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A solid model representing a product requires filleting or blending, which rounds a specified edge or vertex, in order to make a production model for manufacturing purpose such as mould die model. Many research algorithms for blending have been proposed and commercial CAD/CAM system vendors have implemented blend functions for their systems, however, the practicing users of CAD/CAM systems in the manufacturing industry are suffering from the inability of current blending functions, such as some “holes” in the solid models because of the failure of the blending. We regard that the current major solid model structure, the Boundary-Representation (B-rep) lacks the sufficient structure for making robust blending surfaces. In our research, we propose several additional conditions for the B-rep that includes “extended surfaces” that make the blending algorithm simple and robust. In this report, we show that our proposed conditions are effective in the case of three-edge vertex blending. Several examples are shown to verify the effectiveness of our proposal.

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It is extremely important to measure the strength of structures for the inspection of their reliability. Although the measuring of strain using strain gauges is very useful for locating various problems of strength, the strain gauges can measure strains only at points where they are attached. Therefore, the strain gauges are not suited to the measurement of strain distribution at cross sections of structures. On the other hand, it has been reported that the sub-pixel digital image correlation (Sub-DIC) method can measure the strain distribution at cross sections of structures using a high performance digital camera. In this paper we discussed the accuracy under a high strain environment and the localization of fatigue cracks in order to evaluate the efficacy of the Sub-DIC method. The results obtained by the Sub-DIC method were compared with those by the finite element method and the tensile tests. The efficacy of the Sub-DIC method was confirmed.

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