Simulation and experimental investigation of performance characteristics of dry and near dry EDM process

In many industrial applications, necessity of new age materials; however some typical alloys like spring steel material are used in critical sector such as defence, aerospace, and automobile. To work on spring steel material, there are several difficulties such as hard to cut, low material removal rate, and high energy consumption. The EDM is critical thermal evacuation process. This paper presents the result of experimentation and simulation carried out on a spring steel material by varying current, gap voltage, cycle time and pressure. The experimental results are verified by developing a thermal-electrical model of workpiece material using ANSYS workbench. Transient thermal analysis is used to simulate the electric discharge machining. The finite element method (FEM) analysis includes spark radius variation and temperature profile formation by electric discharge. It is found that the dielectric fluid pressure is closely related to the discharge environment, such as debris concentration and fluid viscosity. Further, it is found that distilled water provides more stability to plasma channel in near dry electric discharge machining (NDEDM) compared to dry electric discharge machining (DEDM). From the results obtained, it is concluded that the material removal rate is affected by dielectric medium properties viz. dielectric strength, dielectric constant and thermal conductivity.