A special machining method that utilizes the electroerosion produced by pulse discharge between two poles immersed in theworking fluid to erode conductive materials,
also known as electrical discharge machining or electroerosion machining, or EDM in English. Tool electrodes commonly use corrosion-resistant materials with good
conductivity, high melting points, and easy processing, such as copper, graphite, copper-tungsten alloy, and molybdenum. During the machining process, the tool electrode
also suffers loss, but it is less than the amount of workpiece metal removal, and is even close to no loss.