Papers by Author: M. Ohmori

Abstract: In V-groove ELID grinding process, to achieve optimal grinding performance and satisfactory surface quality and profile accuracy, metal bonded diamond grinding wheels need to be carefully sharpened. In this paper, we applied the proposed new micro-truing method consisting of electro-discharge truing and electrolysis-assisted mechanical truing to sharpen the edge of large grinding wheels. The minimum wheel tip radiuses of 6.3 and 8.5µm were achieved for the #4000 and #20000 grinding wheels. The truing mechanisms and sharpening performance are also discussed.

Abstract: Metal bonded diamond grinding wheels are widely used in the grinding process, especial in ELID grinding. However, truing is difficult owing to the high toughness of metal bond materials and high hardness of diamond abrasives. To realize high precision and high-efficiency truing, we propose a new micro-truing method consisting of electro-discharge truing and electrolysis-assisted mechanical truing in this paper. The process principle and fundamental experimental results are introduced, and the truing performance is discussed. Research results show that the proposed new method is effective for truing metal bonded diamond grinding wheels.

Abstract: Serration phenomenon of sintered and cast chromium was investigated by means of tension test at various strain rates. With increasing test temperature, tensile strength decreased gradually at first and showed a minimum at a certain temperature. Above this temperature, the strength continued to increase to a maximum value. Serrated flow appeared between the temperatures of the minimum and maximum tensile strengths. Tensile ductility minimum was also observed around the temperature of the maximum tensile strength. Relation between the strain rate and the temperature T of the maximum tensile strength could be well described by an Arrhenius equation. Activation energy of 101.3kJ/mol found in the present study is in good agreement with the activation energy for diffusion of nitrogen atom in chromium.