Soft magnetic powder cores are manufactured by pressing pure iron powder covered with insulating film into shape. These are widely known soft magnetic materials, which are used as essential electromagnetic conversion parts. In recent years, demand for higher magnetic properties and dimensional precision has been growing with respect to soft magnetic powder cores. Therefore, it has become necessary to develop a high-efficiency, high-precision finishing method. The issues to be addressed with regard to this type of method are: (1) the pure iron used in these materials displays ductility resulting in burring and cohesion to machining tools; and (2) these materials are green compacts with low binding forces between powder particles and high tendencies toward cracking and gouging. We have solved these issues through the development of a smooth finishing method designed for soft magnetic powder cores.

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Our goal is the development of a design system for mechanochemical superabrasive stones containing both cBN and CeO₂ abrasives. As the first step, we have already developed a morphological structure model for the stone using fractal modeling techniques. As the second step, this paper describes the surface topography model for the stone. We have already proposed a surface topography model for the stone containing only cBN grains. This model can describe the surface topography with the same fractal dimension of grain distribution as the morphological structure model. Therefore, we have improved the model by preparation of the describing parameters for each grain and the changes in these parameters through the describing algorithm. As a result, the model bears resemblance to the real stone in topography and fractal dimension in each grain of the topography model is approximately equal to the morphological structure model.

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A new optical fiber end-tapering machine for on-site use was developed. This apparatus can machine a fiber end in only several seconds by a very simple mechanism. Here, a flat lapping plate was used substituting for a cup-type grinding wheel. We discovered a stable machining position on the lapping plate. Using this position, optical fiber end planes can be machined with good precision and reproducibility.

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Superfinishing is usually used for finishing of cylindrical surfaces, in which high-quality surfaces can be obtained easily and quickly. It is considered that superfinishing may be applicable to surface finishing of curved and flat surfaces of molds. This study was performed to develop a rotation/revolution type superfinishing tool for application to the surface finishing of molds. In this superfinishing tool, the kinetic locus of the grinding wheel and/or abrasive grain can be changed as required by the rotation speed and revolution speed of the grinding wheel. The experimental results clarified that the critical pressure in the finishing process can be decreased by increasing the rotation-to-revolution speed ratio.

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