Electrode insulation layer for electrochemical machining fabricated through hot-dip aluminizing and microarc oxidation on a stainless-steel substrate

Insulation of an electrode for use with an electrochemical machining (ECM) was achieved through hot-dip aluminizing and microarc oxidation techniques. To form an effective insulation layer on a stainless-steel substrate and achieve high precision in ECM, an electrode was processed through microarc oxidation, and the aluminum-rich layer was converted into an aluminum oxide insulating layer. The withstand voltage of the tool was evaluated through sodium chloride electrolysis, and the surface and cross-section were observed. The ECM performance of various tools with and without aluminum oxide insulating layer was examined by drilling on a stainless-steel workpiece. A precise and robust insulation layer must be produced. Precision can be achieved by reducing the stray effects of ECM. Experimental results indicated that the optimal parameters were aluminum dipping were 4 min, microarc voltage of 475 V for 10 min with a withstand voltage of 9.3 V. Electrochemical drilling was used to examine electrodes with and without an insulation layer. Improvement of variation between entrance and exit could be 64.58 %. The differences between the entrance and exit values indicated that the electrochemical insulating layer considerably reduces stray current and improves drilling accuracy.