Experimental study of conventional wire electrical discharge machining for microfabrication

This article discusses the investigation and optimization of the process parameters of conventional wire electrical discharge machining (WEDM) of a copper substrate for microfabrication. The effect of discharge current, pulse-on time, and gap voltage on surface finish were studied. The average surface roughness (Ra) and peak-to-valley height (Rt) were measured with a surface profiler. The surface roughness increased with higher discharge current and gap voltage. With the increase of pulse-on time, the surface roughness decreased. Statistical models were established to predict the surface roughness Ra and Rt in terms of discharge current, pulse-on time, and gap voltage. Using the optimized parameters, miniaturized spur gears, and plate-shaped hot embossing microtools were fabricated where an average surface roughness of about 1 m and dimensional accuracy of 1-2% were achieved.