Abstract: In electro discharge machining, it is possible to decouple the size of tool electrode from the desired size of cavity by actuating the tool electrode on orbital trajectory. In present study, experimental investigation based on Taguchi experimental design is carried out to study the effect of orbital parameters along with machine parameters during orbital EDM process. Copper is used as tool electrode for machining of a nickel based superalloy material viz., Inconel 718. The empirical model has been developed using linear regression analysis by applying logarithmic data transformation of non linear equation. The prediction based on the above developed model has been verified with another set of experiments and are found to be in good agreement with the experimental results. Further, analysis of the results has been carried out using signal-noise ratio formulae and ANOVA to identify the significant parameters and their degree of contribution in the process output.