Rapid Surface Finishing of Stainless Steel Plates by Electrochemical Machining Process

In this paper, the development of a rapid surface finishing method using an ECM process for stainless steel plates of standard size is described. Basic experiments are carried out first with a bar electrode 10mm wide and 3mm thick under a working gap of 0.2mm in order to establish the principle of the finishing process in which a stock removal rate of about 10μm/s is obtained. On the basis of the exprimental results, a trial apparatus which is designed for finishing stainless steel plates of the standard size of up to 5 feet in width is fabricated. It is equipped with a cylindrical electrode of 300mm in diameter to give the maximum peripheral velocity of 10m/s when rotated. Electrolyte is supplied to the working area by not only pumps but also tool rotation. Two masking sheets are extended upstream and downstream, respectively, to restrict the working area to between 8 and 12mm in length. Test runs are carried out to improve the gloss of SUS304 plates 4 feet wide and 8 feet long from the 2B to the BA finish level. The target level of gloss is realized under an electrode gap of 0.6mm with a feed rate of 600mm/min, applied voltage of 35 V and working current of 4000A.