IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684, p-ISSN: 2320-334X. PP 56-61 www.iosrjournals.org National Conference on Advances in Engineering, Technology & Management 56 | Page (AETM’15)” Investigation of Electric Discharge Machining of Inconel 718 Using Special Graphite Electrode Harpinder Singh Sandhu 1 , Vidhata Mehta 2 , Jatin Manchanda 3 , Gurpreet Singh Phull 4 1,2,34 (School of Mechanical Engineering, Lovely Professional University, Punjab, India) Abstract: Electric Discharge Machining is a non-conventional machining process, used to machining difficult to machine materials. The major problem faced while doing EDM is high tool wear rate, end wear, corner wear , surface roughness and low material removal rate,. In this research work experimental investigations have been made to find the machining characteristics of high density ultra fine graphite and Inconel 718 superalloy. The present paper presents the effects of peak current, pulse on-time(Ton) and duty cycle on the output parameters like Material Removal Rate(MMR, End Wear and Surface Roughness(SR). Keywords: Electrical Discharge Machining (EDM), End Wear, Material Removal Rate (MRR), Surface Roughness(SR) I. INTRODUCTION The Electric Discharge Machining(EDM) is by far the most widely used machining process among the non-traditional machining methods. The EDM involves a controlled erosion of electrically conductive materials by the initiation of rapid and repetitive spark between the electrode tool and workpiece, separated by a small gap. This spark gap is either flooded or immersed under the dielectric fluid. The spark discharge is produced by controlled pulsing of direct current between the workpiece and the tool. The dielectric fluid in the spark gap is ionized under the pulsed application of direct current, thus enabling a spark discharge to pass between the tool and the workpiece. Each spark produces enough heat to melt and vaporize a tiny volume of the workpiece material, leaving a small crater on its surface. The energy contained in each spark is discrete and it can be controlled so that the material removal rate and surface finish can be predicted [1].The EDM process was developed for machining difficult to machine material like carbides, hard nonferrous alloys, tool and die steels and superalloys. EDM can be applied to all electrically conducting metal and alloys irrespective of its melting point, toughness, hardness and brittleness[2]. Fragile and slender workpieces can be machined without distortion. It is also successfully employed for producing intricate and irregular shaped profiles common in tool rooms. Now a days the every industry from tool room to big companies in every filed like tool and die, automobile, aerospace and electronics industries is using EDM. EDM chief applications are in the manufacture and reconditioning of press tool and forging dies as well as moulds for injection moulding. Fig 1: Set up of EDM. [3]