Abstract: Based on electrochemical principle, the micro-pin used in micro-machining is fabricated. The shaping mechanism of the micro-pin is analyzed in detail. A model about the process of electrochemical etching is developed. The shape and the diameter of the micro-pin are controlled by precisely determin-ing voltage and time. At the mean time, various parameters that affect the results of experiment are discussed in detail, which include controlling of voltage, current changing, concentration of the electrolyte and effect of time of etching on the diameter of micro-pin etc. The law of micro-pin forming derived from the discussion. The comparison between experiment and theory proves the validity of theory model. Ultimately, a tungsten mi-cro-pin of total long with 1 180 mm are prepared, with which the thinner part of front is 300 mm in length and 6 micrometer in diameter, the aspect ratio is 50:1. The micro-pin could be used in micro machining.

Key words: Electrochemical etching, Micro machining, Micro-pin