A potential difference is applied across the Electrode. An electric spark is generated in between the tool and workpiece. … As the voltage breaks, the dielectric fluid flushes away the molten materials leaving behind a crater.

EDM (Electro Discharge Machining) Wire Erosion is a precision engineering process where a work piece is cut through with a strand of wire, it creates electrical sparks between the wire and the work piece, and these electrical sparks cut the work piece.