Investigation and Optimization of Inconel-718 during Dry EDM

Dry electric discharge machining (EDM) is a new process in which the liquid dielectric is replaced by a gaseous as a medium. The flow of high velocity gas through hollow pipe tool electrode into the gap provides removal of debris and prevents excessive heating of the tool and work piece at the discharge spots. Keeping literature review into consideration and trial experiment in this paper, an attempt has been made by selecting compressed air as a dielectric medium, with Inconel – 718 as a work piece material and copper as a tool electrode. Experiments are performed using Taguchi DoE L27 orthogonal array to observe and analyze the effects of different process parameters to optimize the response variables such as material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra). In the current work, a unit has been developed to implement dry EDM process on existing oil based EDM machine.