Local actuator module for highly accurate micro-EDM

Recently, there are high expectations that electrical-discharge machines will become indispensable equipment for the precise machining of micro-dies and drilling of micro-holes. The authors propose a local actuator module to improve machining accuracy and speed for such applications. The module utilizes electromagnetic force to hold the electrode in mid-air, and then drive it using free to heavy mechanical components. This design realizes a fast frequency response of 200 Hz in each of the X-, Y- and Z-axes directions. In an experiment, it was proven that the module is capable of drilling a micro-hole approximately three times faster than the conventional method while sustaining 10–20% less electrode wear. The module itself is also capable of quick planetary motions for highly accurate machining of micro-dies. These results indicate that the proposed module is practical for improving the micro-machining and more useful for miniaturizing an electrical-discharge machine.