1. The EDM Principle: The process involves a series of rapid, discrete electrical sparks between an electrode (tool) and a conductive workpiece, both submerged in a dielectric fluid (like kerosene or deionized water).
2. Material Removal Mechanism: When the voltage between the tool and work reaches a certain level, the dielectric fluid breaks down, and a spark jumps across the gap.
• Melting: The spark creates an extremely high-temperature plasma channel (ranging from 8,000$^\circ$C to 12,000$^\circ$C). This localized heat instantly
melts a tiny volume of the metal on both the tool and the workpiece.
• Evaporation: A portion of this molten metal is so hot that it instantly turns into vapor (
evaporation).
3. The Role of the Dielectric Fluid: As the spark ends, the plasma channel collapses. The surrounding dielectric fluid rushes into the area, cooling the molten metal and "flushing" away the debris (now in the form of tiny solidified spheres) from the gap. This process repeats thousands of times per second, slowly eroding the shape of the tool into the workpiece.