This paper introduces an analytical method to calculate the stiffness of crossed roller bearings. Load distribution analysis of rollers considering combined radial, axial and moment load makes it possible to apply to three dimensional elastic deformation problems. From equilibrium conditions on forces and Hertz contact theory, relational equations are derived. Solving these non-linear equations numerically with Newton-Raphson method, load distribution and inner ring displacement with fixed outer ring are obtained. Also experiment has been conducted to estimate a discrepancy between the analytical and experimental results. Experimental displacement of inner ring is confirmed to be almost coincident with theoretical one under radial load but smaller than theoretical one by about 20% in the case of axial and moment load. On the other hand the difference between the theoretical and experimental stiffness at higher load is found to be almost the same.

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Water spraying is usually used in the removal of hard dental tissue with laser for the clinical cavity preparation which is previous to the prosthesis. However, the effect of water on the dental tissue irradiated with laser has not been evaluated quantitatively. In this paper, the cavity preparation is performed for human dentin tissue with Nd:YAG laser and Er:YAG laser to investigate the effects of water. The thermal damages caused on dentin tissue are microscopically observed and the perforatability is evaluated from the dimensions of cavity perforated. The thermal damages caused on dentin tissue is reduced by water, especially very fine cavity can be achieved in the cavity preparation with Er:YAG laser, while the perforatability with laser beam is decreased by water. The audible sound pressure level is also measured to investigate the feasibility of sound monitoring as the removal-monitoring method. It is found that the sound pressure level increases linearly with the extent of removed dental tissue.

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By using ultra-high pressure and speed polishing, the research aims to develop the ultra-high removal rate polishing technique under the ultra-smoothness polishing of magnetic disk substrate. In the report, the influence of polisher surface structure on polisher life is experimentally examined and discussed by comparing the change of removal rate with polishing process for two types of polisher surface structures. Polishing pressure ranges from 10kPa to 60kPa under the polishing speed of 1.5m/s. The polishing pressure of 10kPa and polishing speed of 1.5m/s are near the highest in the region of polishing conditions used generally at the present polishing operation. The surface structure of polishers used is single and double NAP layers. In case of the double layer polisher, only the first two steps, that is, the first transitional polishing process and the steady polishing process among the four steps which is found in the change of removal rate with polishing process for the single layer polisher are ascertained. The polisher life can not be found at the polishing pressure of 10kPa. In the ultra-high pressure condition of 60kPa, the removal rate for both the single and double layer polishers becomes about four times larger than that in the 10kPa. The polishing pressure has little influence on surface smoothness.

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The laser forming has a high possibility as a new forming process, since the laser forming process does not need any die or punch. In the laser forming of a metal plate, the bending process is caused by the thermal stresses which are produced in the plate by the laser irradiation. In the present study, the laser forming is modeled by the finite element method (FEM: LS-DYNA), and the bending deformation of the plate is estimated by the FEM. Comparing with the experimental result, the validity of the proposed analytical model of the laser forming is demonstrated. In the numerical examples, the effect of plate thickness and beam diameter on the bending direction is analyzed. It is confirmed that the bending angle decreases as the plate thickness decreases, and that the plate bends the opposite direction on the laser irradiation side and bending angle increases when the plate thickness is thin and the beam diameter is large.

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Laser leveling is an application of laser forming. Laser leveling of a sheet metal is a plastic process caused by thermal stresses which are produced in the sheet by laser irradiation. In this paper, a sphereical distortion on a sheet metal is leveled by laser irradiation. As a model of a circular distortion, the dsitortion is intentionally introduced on the sheet metal by pressing a steel ball of 25 mm radius against it. As work materials, steel sheet and stainless steel sheet whose thickness is 0.6mm are used. Laser beam is radially irradiated at the center of circular distortion for leveling the distorted sheet metal. Continuous CO₂ laser beam is used and its power is changed at the range of 80W ∼ 200W under a constant scanning speed of 2mm/s. After laser irradiation, a distortion of about 400µm hight becomes almost flat without melting a sheet metal.

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This paper proposes a new method of laminated manufacturing using the combination of friction stir welding (FSW) and milling. In the method, FSW is used for joining each plate of the layer, and milling is used for shaping cross sections of the layers. 3-dimensional objects with the complex shape are fabricated by repeating these operations. Process parameters of FSW for lap welding were obtained first through elementary experiments. Then examples to examine the feasibility of the proposed method were manufactured with aluminum and plastics. As the machine with limited power was available, spot welding was adopted in the experiments, and many gaps were included in the experimental objects. To realize more advanced results, the machine with controlled travel speed of the tool should be used. Although, even with the relatively low power machine, such materials as low melting point metals and thermoplastics were proved applicable for this method. As FSW uses economical equipment, the method is beneficial for reducing the cost of manufacturing 3-dimensional objects with various materials.

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This paper proposes a new method for constructing constant radius fillet surfaces and variable radius fillet surfaces from 3D sensed data. In the proposed method, fillet radius distribution along edge between geometrical features is calculated by fitting circles to the 3D sensed data. The shapes of constant radius fillet surfaces and variable radius fillet surfaces are defined by using the fillet radius distribution. The results of applying to simulated datasets and real measured datasets of test pieces show that the error of fillet radius was less than 0.08mm and the validlity of the proposed method was confirmed. The proposed method was also applied to real mechanical part and the effectiveness of the method was confirmed.

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The purpose of this research is to develop a system that can evaluate stability and ease of a person grasping products such as digital cameras without real subjects and physical mockups. In the system, we integrate 3D digital hand models with the 3D CAD models of the product to realize the virtual ergonomic assessment. The system features are the following; i) Geometrically accurate 3D digital hand models with rich Japanese size varieties are used for the assessment, ii) A semi-automatic grasp planning function is installed to efficiently find appropriate grasp posture for the exterior housings geometries of appliances, and iii) "Force-closure" and the "grasp quality" indices can quantitatively evaluate grasp stability for the product.

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This paper addresses Scanning Electron Microscope (SEM). In detail, the image noise caused by the acoustic noise disturbs observation for correct shape of the specimen. Thus, SEM be less influenced by the acoustic noise is expected. This paper approaches to this image noise problem from the damping of the vibration of the base plate. Firstly, the transmission path of the vibrations of the base plate excited by acoustic noise, and the mode shapes of the plate, are explained. Secondary, in order to restrict these vibrations, a tuned mass damper using viscoelastic materials is designed. Using the effect of the shape of the viscoelastic material, the natural frequency of the damper was tuned to lower frequency by dividing the width of the material without decreasing the area of the material. Moreover, the damping factor showed less value when the width of the material was wider than certain value. Thus, it is important to set the ratio of the width and thickness of the material smaller than certain value for keeping the damping factor stable and for wider frequency range of the vibration restriction. Finally, the tuned damper is assembled to SEM, and remarkable restriction of the acceleration on the base plate from 250Hz to 1.3kHz, and remarkable image noise reductions under the acoustic noise excitation on 315 and 400Hz band with third octave band filtered pink noise are shown.

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Large molds with very deep shape are used in producing bumpers and inner panels of automobiles. In order to realize the precise and stable machining of such deep molds, 3-axis milling with inclined cutters is often applied. Some machining regions are difficult to process with a cutter in a single orientation. Such regions must be subdivided into several smaller regions, so that each region can be processed with a single orientation cutter. We propose a new algorithm for automatically subdividing the machining region. A machining region is represented as a set of cubic blocks in our study. For each block, all accessible directions of a cutter are computed. Neighboring blocks with similar cutter accessible directions are then combined, and some groups of blocks with similar cutter accessible directions are obtained. Proposed algorithm is implemented and an experimental process planning assistance program using this technology is demonstrated.

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This paper describes a real-time translational velocimetry for the high speed tracking of a transparent floating cell by the optical visualization. This tracking technique optically visualizes a transparent cell as the fringe of sinusoidal intensity distribution, and measures the velocity by a high-response PD (Photodiode). Conventionally, we proposed the optical visualization method which derives the specific spatial frequency component from the sample by introducing two pinholes as a spatial filter on the optical Fourier transform plane, and made transparent cell visualize as the fringe. However, to realize the high speed tracking, the real-time measurement of moving velocity for the fringe by PD is needed. Therefore, we detect the phase information that linearly varies in accordance with the fringe position. In this phase detection, the double slits with a phase different of π/2 is installed on the imaging surface, and each transmitted light is separately received by the split PD. Herewith, the output wave of sine and cosine can be simultaneously obtained. By calculating the phase information as the arctangent from the vector locus, instantaneous velocity can be measured. We verified the possibility of measuring velocity in real time using the pixel array of the CCD as virtual slits.

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