Numerical simulation of electric discharge machining of functional graded material

Abstract

In the present scenario, advanced material is required for higher end applications whose material properties can be preassigned according to the performance demands. This lead to the development of functional graded material. These kinds of materials are divided into different layers with varying material properties. The Functionally Graded Materials are heterogenous in nature but in layer wise it can be considered homogenous in nature. The material properties can be calculated by using Rule of Mixture. However, this material possesses challenges during the machining process. Machining of these materials using conventional process is challenging due to its improved mechanical properties. However, such materials can be machined using unconventional machining processes. This work involves a development of finite element simulation model to simulate the Electric Discharge Machining (EDM) process on Functional Graded Material (FGM). The EDM is a material removal process through multiple occurrence of single spark on the workpiece. This single spark will create a crater due to the excess heat of the spark and the molten material can be removed by using the dielectric fluid. The heat input for a single spark can be defined by using the Gaussian distribution of the spark profile. The centre point will have maximum heat inputted and as the heat passes in the work piece it decreases. The size of the crater will vary with the varying the process parameters such as Discharge current, Discharge Voltage, Pulse on-time, off-time and Energy Partition. The effect of the process parameter on material removal rate (MRR) is evaluated using the FEM simulation. The predicted result shows that with increase of pulse on-time and discharge current, the crater size was found to be increased. This increase in the crater size attributes in the increment of MRR. The predicted results can enhance the machining process of FGM.