Finite element of modeling and analysis of powder mixed electric discharge machining for single and multiple craters

Abstract

Electrical Discharge Machining (EDM) is one of the most extensively used non-traditional material removal process for very hard, tough, high strength but electrically conductive materials. Mixing of powders into dielectric fluid is a one of the recent advancement in the EDM process to improve its process capabilities and is known as Powder Mixed EDM (PMEDM) process. Present work aimed to study the thermal aspects of PMEDM process using finite element analysis. Temperature distribution and volume removal for single and random multiple craters are analyzed by suitably modeling the process and considering temperature dependent material properties. A gradually growing spark behavior and Gaussian distribution of heat source is used to simulate for both single and multiple craters. Temperature distributions along the radial and depth direction of the crater are analyzed and subsequently used to estimate volume removal at different process settings. Development of different temperature zones like unaffected, heat affected, melting and evaporation zone, shape and size of crater for different current, pulse on and fraction of heat to work piece have been studied. Temperature distribution during simulation is found to be the maximum at the center of spark region and decrease in the radial direction in both cases of single as well as multiple overlapped craters. Peak temperature and total volume removed is found to be more influenced by the discharge current as compared to fraction of heat supplied to work piece. Results also show that after a certain discharge current and heat fraction, proportion of volume removed due to evaporation increases. For multiple spark analysis, variations of temperature after each spark are analyzed and successive removal of volume is analyzed for different parameter settings.