Fabrication of cylindrical micro tools by micro electrochemical form turning operation

Cylindrical micro tools of tungsten material have various applications in micro devices and systems because of its high rigidity and toughness. This article deals with the fabrication of cylindrical micro tools from tungsten rod by micro electrochemical form turning operation using KOH solution as electrolyte. The experiments were conducted with an indigenously developed setup with the variation of different experimental parameters to get good cylindrical shape of the tool. Cylindrical micro tools of diameter less than 50 mu m and length of up to 1 mm have been fabricated through this process from tungsten rods of initial diameter of 1.5 mm within the time duration of 15 min. This process produces cylindrical micro tools from a much larger initial diameter of tungsten rod and with low lead time, as compared to the reported literatures. The variation of the cylindrical length of the micro tool according to the variation of parameters such as pulse on time, applied voltage and concentration of electrolyte has been analyzed, and the optimum parameter settings for getting the better shape and surface finish of the cylindrical electrode are electrode gap distance of 100 mu m, frequency of the pulse power supply of 500 kHz, voltage of 18 V, electrolyte concentration of 3 M and pulse on time of 1400 ns.