Electrical Discharge Machining of S G Iron: Effect of Process Variables on Material Removal Rate and Overcut with Multi-Optimisation

Electrical discharge machining (EDM) process can be used effectively to machine S G Iron if mathematical models correlating the input process parameters and the major outputs are developed. The primary objective of this work is to develop mathematical models based on the design of experiments to correlate the controllable process parameters of EDM with major outputs like material removal rate (MRR) and overcut. The functional requirement such as high MRR together with low overcut depends on a number of process variables. Hence, the next objective is to use multi-criteria optimisation based on desirability function to find out the value of operating parameters that will ensure a high rate of material removal along with low overcut. Central composite design is practised here to develop the mathematical models. The variation in outputs along with process parameters are explained with the help of developed models. The values of operating parameters for high MRR with low overcut conditions are also found. The work material is S G Iron of grade 450/12.