Journal of The Japan Society of Electrical Machining Engineers

Study on Electric-Discharge Machining

Cracks on Machining Surface

HISAO KURAFUJI, YOSHITSUGU MUKOYAMA

1969 Volume 3 Issue 4 Pages 3-21
Published: March 31, 1969
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.3.3

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Although it was found out that in order to improve the machining efficiency it was important to increase the thermal efficiency by regulating the discharge duration, this would increase the risk of Occurrence of the defects on the machining surface, especially, cracks.
Therefore an experiment was conducted for causing cracks on the machining surface of cemented carbide tip and at the same time, the cause of occurrence of cracks was analysed from the viewpoint of the thermal conduction theory.
And it was proved that the thermal action is the main cause of the occurrence of cracks from the fact that both the results of the experiments and those of the analyses agreed well.
An attempt was also made to improve the remove characteristics on the cemented carbide alloy.

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Study on High-Speed Electrical Discharge Machining

Hisao KURAFUJI, Ko SUDA

1969 Volume 3 Issue 4 Pages 22-33
Published: March 31, 1969
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.3.22

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New techniques on high-speed electrical discharge machining are described in this paper. Mixing of conductive powder in working fluid enables electrical discharge between on electrode and a work piece very easily and frequently, increasing the erosion rate remakably. The working fluid spond be passed through at a certain velocity between an electrode and a work piece. By superposing electric pulses of relatively high voltage on the electric sourse of low voltage and of high current capacity, such a high erosion rate as 145g/min is obtained with only 31KW power input. Several improvements in electrode shape and in supply of working fluid are proposed to get easy flow of working fluid in deep-hole machining, thus to keep the erosion rate high in the case.

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[title in Japanese]

[in Japanese], [in Japanese], [in Japanese]

1969 Volume 3 Issue 4 Pages 34-41
Published: March 31, 1969
Released on J-STAGE: March 12, 2010

DOIhttps://doi.org/10.2526/jseme.3.34

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