An Experimental Investigation and Optimization of Electrical Discharge Drilling for Small Hole Drilling with High Aspect Ratio

Electric discharge drilling (EDD) is a thermo erosion processused to produce micro/smallholes in hard and composite materials. EDD is mostly used to drill small holes in products for several applications such as fuel injector, dentaland medical devices, turbine blades cooling channels etc. In present work, small holes of diameters () 0.5 mm and 1mm are drilled in Die steel using tubular electrodes of copper and brass. Using Taguchi design of experiment method, process parameters namely discharge current (Ip), pulse on time (Ton), pulse-off time (Toff) and electrode material are investigated and optimized for different hole geometries using electrodes of 1 mm& 0.5 mm. In EDD process, drilling capability and diametric over cut (DOC) are the performance characteristics under investigation. Using Grey relational analysis (GRA), both performance characteristics are optimized simultaneously.