Abstract: The rapid development of micro electromechanical systems (MEMS) and the miniaturization trend of products require much higher machining quality for micro structural surfaces such as micro hole, micro groove and micro prism/pyramid and so on. In order to improve the machining quality of micro structural surfaces, a new method of abrasive assisted electro discharge machining (EDM)and electro chemical machining (ECM) compound machining is provided. The machining mechanism is analyzed by its micro machining model. Micro machining equipment is set up. Process parameters are optimized. Blind and through holes are drilled on SUS 304 stainless steel using tungsten electrodes whose diameters are 500 μm and 75 μm separately. The results indicate that abrasive assisted EDM & ECM compound machining obtains the highest surface roughness (Ra15 nm) among the three methods of EDM, EDM & ECM compound machining and abrasive assisted EDM & ECM compound machining. Therefore, this is one of the best methods which can be used to machining micro structural surfaces with high efficiency and high quality.

Key words: Electro chemical machining, Electro discharge machining, Structural surfaces