The feasibility of electrochemical drilling and milling on stainless steel are investigated using tungsten microelectrode with 10μm in diameter. For the development of environmentally friendly and safe electrochemical process, citric acid solution is used as electrolyte. A few hundred nanoseconds duration pulses are applied between the microelectrode and work material for dissolution localization. Tool fracture by Joule heating, micro welding, capillary phenomenon, tool wandering by the generated bubbles are observed and their effects on micro ECM are discussed. Occasionally, complex textures including micro pitting corrosion marks appeared on the hole inner surface. Metal growth is also observed under the weak electric conditions and it hinders further dissolutions for workpiece penetration. By adjusting appropriate pulse and chemical conditions, micro holes of 37μm in diameter with 100μm in depth and 26μm in diameter with 50 μm in depth are drilled on stainless steel 304. Also, micro grooves with 18 μm width and complex micro hand pattern are machined by electrochemical milling.
