There is increasing demand to reduce friction in engine and transmission parts. Friction between sliding surfaces can be reduced by processing micrometer-scale surface texture with controlled cross-sectional geometry. The authors have developed 3-dimensional micro-forming technology to fabricate such controlled surface textures at high efficiency. In this study, CAE analysis of 3-dimensional micro-forming technology was performed. Basic plastic deformation phenomena between the workpiece and tool during the process are discussed in detail. Furthermore, the effects of tool shape on machining accuracy and tool life is discussed, and thereby guidelines to optimize tool shapes were developed.

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Lapping is using in the manufacturing processing to make silicon wafers as substrates for semiconductor chips. This process is used to make parallel wafers surfaces using a slurry by the relative motion between the lapping plate and wafers. In this process, the stability of slurry supply is important for high precision and efficiency. Therefore, the lapping plate contains many grooves to supply slurry. However, as it is too difficult to observe the slurry actions during the lapping process, the relations between the groove shapes of the lapping plate and the slurry actions are not clear. This study used a grooved soda glass model of the grooved lapping plate to visualize slurry flow in the grooves. Here, we describe the relations between the slurry flow and the shape or size of the grooves.

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Powder jet machining can be used for material removal (abrasive jet machining) and material deposition processes (powder jet deposition) by varying the powder spray conditions. However, the transition conditions have not been investigated. The phenomenon of alumina particle impact onto a glass substrate was simulated with smoothed particle hydrodynamics (SPH) method to analyze the fracture of the substrate in this paper. The results of the calculations showed that the fracture markedly increased at a particle velocity of 400 m/s, and the velocity was therefore considered to be a significant criterion. The relationship between the particle velocity and the machining phenomenon was investigated experimentally. The results indicated that the machining phenomenon transited from the deposition process to the removal process at a particle velocity of 400 m/s.

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The wear characteristics between single-crystal diamond and glass (BK7) were investigated. This experiment was performed to investigate the cause of single-crystal diamond tool wear that occurs with glass cutting. In this experiment, we investigated the relations between the single-crystal diamond wear volume and the normal load and friction speed. The results indicated that the wear volume of the single-crystal diamond increased with increasing normal load and friction speed. Moreover, we explored the friction surface and triboluminescence of single-crystal diamond and BK7 using Raman and spectroscopic analyses. Graphite was detected from the friction area of BK7 and tribomicroplasma was detected from triboluminescence. No diamond was detected from the friction area of BK7, suggesting that single-crystal diamond changed to graphite and wore out due to friction.

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