Effect of coated and treated electrodes on Micro-EDM characteristics of Ti-6Al-4V

This research work was carried out to find a suitably treated electrode for the required machining output response like MRR and TWR. The experimental design was formed using Box-Behnken design. Experiments were conducted to machine 500 mu m holes on titanium (Ti-6Al-4V) alloy using copper electrodes. Input parameters selected were input current (I-p), pulse-on time (T-on), and pulse-off time (T-off). Material removal rate and tool wear rate were analyzed using contour plots. Based on these experimental data, the grey relational analysis technique was applied to find the optimal parameters for achieving maximum MRR and minimum TWR. Optimal parametric values obtained were input current (I-p) 4.0 A, pulse on time (T-on) 2.0 mu s and pulse off time (T-off) 6.4 mu s. The achieved optimized parameters were further used to conduct experiments with cryogenic treated and coated electrodes. Electrodes were coated with conductive materials (silver, nickel, and zinc) and non-conductive material (epoxy). The experimental results showed each type of electrode enhances a particular machining characteristic such as silver-coated electrode produced a higher value of MRR, epoxy-coated electrode achieved minimum TWR. It is observed from the results that this work can be applied to identify the suitable electrode for producing the desired machining output characteristics.