Experimental analysis for enhancing surface integrity of micro-slots in Hastelloy-X superalloy via electrochemical machining

Micro electrochemical slotting presents significant potential in the precision manufacturing of advanced engineering materials, particularly in applications requiring high strength and corrosion resistance, such as gas turbine components and biomedical devices. This study investigates the impact of different machining settings, such as tool feed rate (TFR), applied voltage, tool insulation methods and pulse current on the performance metrics of rate of material removal (MRR) and roughness of the surface (Ra) during micro-slotting in Hastelloy-X superalloy. A specially constructed 3-axis micro-electrochemical machining (ECM) system, intended for high-precision operations at the micro scale, was used to conduct the research. The study also explores the impact of tool material conductivity, specifically comparing copper and SS316L electrodes, on the process outcomes. Experimental results indicate that applied voltage and TFR are the most significant factors affecting MRR and Ra. The highest MRR and lowest Ra were achieved with the SS316L and copper tool electrodes, reaching 1.678 mg/min and 0.803 mg/min, and 0.033 µm and 0.027 µm, respectively. Detailed microstructural analysis of the machined micro-slots provided insights into surface integrity, highlighting critical aspects necessary for micro device applications.