No.4（2001）9.Development of processing technology of micro-hole by micro-EDM

Minoru YAMAZAKI, Noritoshi MORI, Kenzaburo TAKEI and Masanori KUNIEDA

This paper discribes a new method for micro-EDM drilling which utilizes the wear of an electrode rod. In this method, the polality of the electrode rod is positive, and the rotating electrode rod is fed into the electrode block at a feed rate of several ten times higher than the normal one. Since the circumferential region of the electrode rod wears at a much higher rate than the central region, the end of the electrode rod is sharpened in a few minutes. At the same time, a cone-like micro-hole with a sharp bottom shape is generated in the electrode block automatically. The results are as follows:

1. The feed speed influenced the needle-shaped length. 60μm/s was the most suitable. At this time, the needle-shaped length became short as the speed increased beyond the most suitable speed.
2. The number of rotations influenced the needle-shaped diameter and needle-shaped length. When the number of rotation is rose, the needle-shaped length became long, and the needle-shaped diameter becames small.
3. Energy influenced the needle-shaped length and needle-shaped diameter. When the energy increased, the needle-shaped length became long, and the needle-shaped diameter became small.

Keywords
Micro-EDM,Micro-machining,WEDG,Tapered-hole,Tapered-rod

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