Special machine tools that utilize electrical energy for precision machining of metal materials. Including wire EDM machines, die-sinking EDM machines, and small hole EDM machines, these are specialized for precision machining of difficult-to-cut materials such as cemented carbide and hardened steel. Material removal occurs through electrical discharge phenomena between electrode and workpiece, requiring no mechanical cutting force and enabling complex shapes and micro-machining. Essential equipment for high-precision machining in mold manufacturing, aerospace components, and medical device parts, with NC-controlled automatic operation as mainstream. These machines achieve clear differentiation from other machine tools in machining hard materials and thin-walled parts that are difficult with conventional cutting processes.