External force assisted electro discharge machining of SS 316

Abstract

Abstract Hybrid electro discharge machining came into the scenario of macro machining due to the need of more rapid machining process with improved efficiency of non conventional machining process. Electro-Discharge Machining (EDM) is a kind of non conventional machining specially used for drilling the holes of required dimensions aspect ratio. Earlier, vibration assisted EDM had came into existence to improve the efficiency such as increase in the metal removal rate, reduction in the electrode wear rate, and decrease in radial overcut of the surface of machined workpiece. But this technique of vibration assisted EDM process did not proved to be successful due to some disadvantages like increase in tool wear for low melting and comparatively softer tool material. Also vibration of workpiece material affects the circularity of holes produced by EDM process. There always exist a need for more advanced hybridised process to improve the overall machining efficiency specially circular shape and radial overcut. In this paper, an external force assisted called permanent magnetic field force assisted EDM process has been carried out with tungsten carbide tool of 5 mm diameter and SS 316 plate of 1.6 mm thickness. Measured performance characteristics like electrode or tool wear rate and diametral overcut represented satisfactory results with permanent magnetic field induced EDM process. The effects on MRR, TWR and diamteral overcut of SS 316 have been analyzed by the related software. It has been found that tool wear and diametral overcut has been found to be reduced with magnetic field assisted EDM than conventional EDM process. Also, machining time is reduced to a certain extent with this new technique of hybridisation.