Can someone tell me the operating theory of EDM – Electronic Discharge Machining? Thks.?

Question by Alex: Can someone tell me the operating theory of EDM – Electronic Discharge Machining? Thks.?
I’m learning on tooling and come across this term. I need to know the working principle of it.

Best answer:

Answer by ag_iitkgp
Electrical discharge machining (or EDM) is a machining method primarily used for hard metals or those that would be impossible to machine with traditional techniques. One critical limitation, however, is that EDM only works with materials that are electrically conductive. EDM can cut small or odd-shaped angles, intricate contours or cavities in extremely hard steel and exotic metals such as titanium, hastelloy, kovar, inconel and carbide.

Sometimes referred to as spark machining or spark eroding, EDM is a nontraditional method of removing material by a series of rapidly recurring electric arcing discharges between an electrode (the cutting tool) and the work piece, in the presence of an energetic electric field. The EDM cutting tool is guided along the desired path very close to the work but it does not touch the piece. Consecutive sparks produce a series of micro-craters on the work piece and remove material along the cutting path by melting and vaporization. The particles are washed away by the continuously flushing dielectric fluid.

There are two main types of EDM machines, ram and wire-cut.

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