MODELLING OF THE MECHANISM OF MATERIAL REMOVAL IN ELECTRO-DISCHARGE MACHINING USING FINITE ELEMENT METHOD

Abstract

Among all the non-conventional methods of manufacturing, Electro-Discharge Machining process is considered to be one of the most important and useful process. It was first started in U.S.S.R., around 1943. It has a great potential to machine tool die steels. It had got its very important role in automobile and aerospace industries, due to its superior property that it is a force free process. To machine a brittle and hard material, it is very effective. However, the material removal mechanism during EDM process is not yet well understood. Due to temperature variation there are very high residual stresses developed in the-EDMed surface. So it is necessary to investigate and understand the material removal mechanism in EDM for improving its efficiency. In this work, the study of mechanism of material removal in brittle material with emphasis on High Speed Steel (HSS) is carried out using Finite Element Method. The ANSYS software has been employed to model the problem and the same is used to evaluate the temperature and stress distribution in the material. An attempt is made to correlate the temperature and stress distribution patterns with the failure of the HSS workpiece. An attempt has been made to find the material removal rate from the FEM model. Further experiments are carried out to validate the results obtained by the developed FEM model for different values of current, pulse ontime and discharge voltage and find which parameter is affecting the material removal rate most. 111