Enhancing electrochemical micro-drilling of A286 superalloy using different tool materials

A286 superalloy is widely used in fuel injector nozzles, afterburner components and turbine blades due to its high-temperature strength and corrosion resistance. Achieving precise microfeatures on such alloys demands Electrochemical Micromachining (ECMM) process. Tool material selection plays a critical role in determining machining accuracy and surface quality. This study compares three cathode tool materials copper, polygraphite (PGT) and tungsten (W) for micro-drilling A286 under an ethylene glycol (EG) + NaNO₃ electrolyte. Performance metrics such as material removal rate (MRR), taper angle, radial overcut, and surface roughness were analyzed. Results show that copper achieved the highest MRR, being 1.25 and 1.88 times greater than tungsten and polygraphite at higher parametric levels. Tungsten proved superior in geometrical accuracy with lowest radial overcut, minimal taper angle, and better surface finish whereas polygraphite exhibited highest taper angle and overcut. Overall, copper is preferable for maximizing productivity, while tungsten is recommended for precision-critical micro-hole applications.