Investigation of electrochemical machining on SS304 using NaCl and NaNo3 as electrolyte

In electrochemical machining (ECM), the material in the workpiece is removed in a localized electrochemical dissolution process, and metal oxides are formed as by-products. In this study, the electrolyte is present only above the workpiece, and the electrolyte thickness is maintained as 2 mm to limit the variation in radial current flow from the micro-tool. In this research work, experiments were conducted using two electrolytes, namely, NaCl and NaNO3, to machine through holes on a 1-mm-thick SS 304 workpiece, using a hollow tool of outer diameter 261 mu m. The pressurized electrolyte was sent through the hollow tool to remove the metal oxides formed in the machining zone. A fixture was designed and used for the identification of through holes. Two sets of L16 orthogonal array (OA) were applied; the factors selected for this experimental study were voltage, electrolyte concentration, electrolyte temperature, and pressure. The output responses considered are radial overcut, taper angle and material removal rate (MRR). Analysis of variance (ANOVA) and Taguchi techniques were utilized in the analysis of results. The results showed voltage and concentration of the electrolyte as the major influencing factors, while the influence of stray current was controlled using NaNO3.