Performance analysis of iso current pulse generator on machining characteristics in EDM process

Abstract

Extremely hard materials can be easily machined by Electrical Discharge Machining process due to its thermal erosion nature. In this process, the amount of material removed is directly proportional to the discharge current. Due to the stochastic nature of the thermal erosion process, the discharge current is varied for every applied electrical pulse. It results in different levels of material removal over the material surface during machining process. The volume of the crater is determined by the discharging energy. The variation in the discharging energy produces high surface roughness, which is influenced by discharge current. A constant duration discharge current is needed throughout the process to produce better surface quality. In this research, an iso duration current pulse generator has been proposed to achieve good surface finish. An experimental performance evaluation has been conducted with conventional transistor pulse train generator and modified iso current pulse generator by Taguchi L27 orthogonal array design. The machining characteristics have been evaluated for both the pulse generators. It is found the that modified iso duration current pulse generator has produced better surface quality with higher material removal rate than the conventional transistor pulse train generator.