Optimization of Various Machine Process Parameters on the Surface Roughness in EDM for an En21 Material using Anova

In manufacturing industries right selection of manufacturing condition is one of the most important aspects taken into consideration in the majority of processes and particularly in processes related to Electric Discharge Machining (EDM).The EDM is a non-traditional machining processes that involved a transient spark discharges through the fluid due to the difference between the electrode and the work piece. EN 21 materials has 3% nickel steel capable of being heat treated to produce an excellent resistance to shock combined with a tensile strength. It is obtained by water hardening and tempering for best combination of mechanical properties. The EDM process is finding out the effect of machining parameter such as discharge current, pulse on time and pulse off time of EN21 material. In this project we have determination surface roughness of EN21 material by changing machine process parameters of an EDM. We have used to Taguchi method and L27 orthogonal array are to reduce the number of experiment. We have got the 5.826 μm surface roughness value at current 14A, pulse on time 20μs and pulse off time 200μs. The ANOVA technique was used for identifying the most significant factor and interaction plot of process parameters on surface roughness. From ANOVA, it is observed that for Ra the discharge current and pulse on time was most significant factor.