Electrochemical micromachining of galvanized iron sheets: process optimization and performance evaluation

Electrochemical micromachining (ECMM) is a promising non-traditional technique for fabricating micro-features on conductive materials with high precision and minimal thermal effects. This study focuses on the ECMM of galvanized iron (GI) sheets using sodium nitrate (NaNO3) as the electrolyte. Key process parameters such as voltage, duty cycle, and electrolyte concentration were optimized to improve machining performance in terms of material removal rate (MRR) and overcut (OC). An L9 orthogonal array was used to design the experiments, and signal-to-noise ratio, along with analysis of variance (ANOVA), was employed to identify the most influential parameters. Results showed that voltage signi­ficantly influenced both MRR and OC, with optimal MRR observed at 12 V, 70 % duty cycle, and 20 g l-1 NaNO3 concentration. Conversely, the minimum OC was achieved at 6 V, 50 % duty cycle and 10 g l-1 NaNO3 electrolyte concentration. SEM analysis confirmed over-etched boundaries at higher voltage and well-defined micro-holes at lower voltage. This research demonstrates the critical role of parameter tuning in enhancing the quality and precision of ECMM on GI sheets.