Investigating the Performance of EDM Process using Tool Rotation Methodology for Machining INCOLOY 800HT Sourabh Sinha *1 , Raj Ballav 2 , Amaresh Kumar 3 Department of Manufacturing Engineering, National Institute of Technology, Jamshedpur, India - 831014 1 sourabhmilan@gmail.com 2 rballav.prod@nitjsr.ac.in 3 akumar.prod@nitjsr.ac.in Abstract—Electrical discharge machining (EDM) being one of the most earliest and accepted non- conventional machining process is used in achieving intricate shapes in difficult to machine materials. Material removal rate (MRR) is one of the machining performances measures which are always discussed while adopting any machining process. In this paper tool rotation methodology has been adopted to observe the effect on MRR while machining INCOLOY 800HT using EDM. The experimental results show that tool rotation improves the MRR of the machined material. Keyword-Electric discharge machining (EDM), INCOLOY 800HT, Response surface methodology (RSM), Box-Behnken, Material removal rate (MRR) I. INTRODUCTION To achieve precise complex shapes manufacturers nowadays uses non-conventional machining processes compared to conventional processes. Benefit of using non-conventional processes over conventional processes ranges from shorter span of machining time to machining of hard materials with complex shapes [1]. EDM uses thermal energy to machine materials which are hard to machine and electrically conductive in nature. EDMs are used to manufacture die, moulds, and automotive, surgical and aerospace components [2]. There is no direct contact between the workpiece and the electrode in EDM, hence eliminating mechanical stresses chatter and vibration problems during machining [3]. In EDM metal is removed from the work piece in the form of erosion as a result of recurring spark discharge taking place between tool and the work piece through the dielectric medium [4]. INCOLOY 800HT (registered trademark of Special Metals, USA) is a Nickel based super alloy having characteristics of high creep rupture strength and great corrosion resistance in acidic and sulphur containing atmosphere. Nickel based super alloys are generally used in petrochemical industries, electric power generators, gas turbines, chemical processing plants requires high temperature and high pressure resistive materials [5]. Having such extraordinary properties, INCOLOY 800HT are used in various industries such as, chemical and petrochemical processing industries for heat exchangers, super-heater and re-heater in power plants, heat treating equipments, and ethylene furnace quench boilers. According to the study presented by Nickel Development Institute and Special Metals Corporation, USA, INCOLOY 800HT is a difficult to machine alloy with the use of conventional machining processes. Therefore, non-conventional machining process as EDM is considered for the present study. The main deficiency of EDM process is its low MRR. In the recent years researchers have adopted different methodologies to overcome this drawback. Tool rotation methodology is a good alternative to enhance the performance of the basic EDM process. The present work is aimed at increasing the MRR of EDM using tool rotation methodology. II. EXPERIMENTATION The experimental set-up used in experimentation for the present study is shown in Fig. 1. Experiments have been performed on AGIE 250C die-sinking EDM machine manufactured in Switzerland. The experiments were designed using Box-Behnken design of experiments as it avoids corner points and star points [6]. Box-Behnken design of experiment as per response surface methodology helps in optimizing a process using a small number of experimental runs. The design was generated and analysed using the MINITAB statistical software. INCOLOY 800HT (Dimensions: 30mm x 30mm x 10mm, and Composition: Ni=30.0-35.0%, Cr=19.0-23.0%, Fe=39.5% min., C=0.06-0.10%, Al=0.25-0.60%, Ti=0.25-0.60%, Al+Ti=0.85-1.20%) is selected as work material because of its high creep rupture strength, high temperature strength, and high corrosive resistant strength. The electrode material consumed for the present work is copper electrode of 15mm diameter which is 99.99% Cu. ISSN (Print) : 2319-8613 ISSN (Online) : 0975-4024 Sourabh Sinha et al. / International Journal of Engineering and Technology (IJET) DOI: 10.21817/ijet/2017/v9i2/170902321 Vol 9 No 2 Apr-May 2017 461