Evaluation of the application value of different parameter optimization methods in electrochemical machining from micro-morphology investigations

The orthogonal experiments of electrochemical machining (ECM) of 2Cr13 stainless steel were conducted. There were many process variables such as working voltage, rotational speed, interelectrode gap, duty cycle, and pulse frequency involved in ECM, and it was difficult to determine an appropriate parameter combination to minimize material removal thickness and surface roughness for electrochemical polishing. For obtaining the optimal processing parameters of ECM, the analyses of variance (ANOVA) and grey relational analysis (GRA) were used to optimize the experimental data. The solutions acquired by the analysis of ANOVA and GRA were compared and experimentally validated. Despite the divergent optimal parameter combinations, the confirmation experiments recorded almost the same removal amount and surface roughness after 15 min of processing time, the high-quality surface of the samples were obtained. As the comparison strategy to evaluate the two data processing methods, the observation results of micro-morphology revealed that the surface of the samples processed with the optimal parameters obtained by GRA had more attractive surface flatness with the Sz of 1.5640 μm than that with the Sz of 1.8820 μm obtained by ANOVA, which verified the application of GRA in the superiorization methodology. This study provided an idea for the selection of optimal processing parameters obtained by different analysis methods in ECM, and high-quality surfaces were obtained.