Using a nickel electroplating deposition for strengthening microelectrochemical machining electrode insulation

Abstract

This study focused on reducing the peeling phenomenon of electrode insulation layers during electrochemical microgroove machining. An epoxy resin insulation layer was applied to the electrode surface, and the tip of the electrode was ground to reveal bare metal for target machining. During electrochemical machining, the durability of insulation under various potentials and processing times were studied. Typically, a large number of hydrogen bubbles are generated at the exposed part of the electrode during processing. These bubbles increase the peeling speed of the insulation and reduce its service life. Therefore, this study proposed the use of electroplating deposition to form an electroplated layer on the exposed part of the electrode. The deposition rate of the electroplated layer and coating state of the electroplated layer at the tip of the electrode were studied. The withstand voltage test was performed under various electrochemical machining parameters to study the insulation and peeling effects. The surface morphology of microgrooves produced through electrochemical microgroove processing with and without an electroplated electrode was compared. The comparison revealed that the uniformity of the microgrooves processed by the electroplated electrode was better and the insulation of the electrode had lower cracked area than those produced without the electroplated electrode. The electrode was tested before and after processing to verify the protective effect of the coated layer. The result revealed that the electrode with a 0.5 mm thickness exhibited the slowest cracking rate, and the electrode with the electroplating time of 4 h exhibited the most efficient protective effect. Thus, the electroplated layer can effectively protect the insulation and prevent it from peeling off during the process, which increases its service life.