Comparison of EDM and ECM machined AISI 304 steel: Surface roughness, hardness and morphological characteristics

In past two decades electro chemical machining (ECM) and electric discharge machining (EDM) processes have been widely explored for machining of different grades of steel (including AISI 304). Although there is difference in material removal mechanism of EDM (localized heating and vaporization being thermal process) and ECM (ionic dissolution being electrochemical energy based process), yet the user needs broad data base for comparison and selection of particular process. But hitherto little has been reported on relative comparison of EDM and ECM processed AISI steel surface from surface roughness (Ra), surface hardness (HV) and morphological characteristics view point. This paper reports the comparison of AISI 304 steel machined surface by EDM and ECM. The comparison has been made after process optimization of EDM and ECM separately (using Taguchi approach). The results of study suggest that ECM is better process than EDM from Ra view point (3.10 µm for ECM and 6.41 µm for EDM) and porosity% view point, whereas from HV viewpoint no significant difference was observed.