An Experimental Investigation of Machinability of Inconel 718 in Electrical Discharge Machining

(BQ)This paper proposes an experimental investigation and optimization of the various machining parameters for the electrical discharge machining (EDM) processes on Inconel 718 super alloy using a multi objective particle swarm optimization (MOPSO) algorithm.
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An Experimental Investigation of Machinability of Inconel 718 in Electrical Discharge MachiningAvailable online at www.sciencedirect.comScienceDirectProcedia Materials Science 6 (2014) 605 – 6113rd International Conference on Materials Processing and Characterisation (ICMPC 2014)An Experimental Investigation of Machinability of Inconel 718 inElectrical Discharge MachiningChinmaya P Mohanty*, Siba Shankar Mahapatra, Manas Ranjan SinghDepartement of mechanical Engineering, National Institute of Technology,Rourkela,Odisha,India,769008AbstractThis paper proposes an experimental investigation and optimization of the various machining parameters for the electricaldischarge machining (EDM) processes on Inconel 718 super alloy using a multi objective particle swarm optimization (MOPSO)algorithm. A Box-Behnkin design of response surface methodology has been used to collect data for the study. The machiningperformances of the process are evaluated in terms of material removal rate (MRR) and surface quality which are functions ofprocess variables such as open circuit voltage, discharge current, pulse-on-time, duty factor, flushing pressure and tool material.Mathematical model is developed relating responses with process variables. Finally, a MOPSO algorithm has been proposed forthe multi objective optimization of the responses.© 2014 The Authors. Published by Elsevier Ltd.© 2014 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/3.0/). the Gokaraju Rangaraju Institute of Engineering and Technology (GRIET).Selection and peer-review under responsibility ofSelection and peer review under responsibility of the Gokaraju Rangaraju Institute of Engineering and Technology (GRIET)Keywords: Electrical Discharge Machining;Inconel 718;Response Surface Methodology;Multi Objective Particle SwarmOptimization ;1. IntroductionThe non-conventional machining processes are more capable than conventional machining process owing to easeof machining of hard materials with complex shapes in the shortest span of time. Now-a-days, electrical dischargemachining (EDM) is extensively used for machining of toughened and high strength to weight ratio conductivematerials which are difficult enough to be machined by conventional machining processes. The process has manyapplications in manufacturing of dies and moulds in manufacturing industries and components in aerospace andautomotive industries. Lee and Li (2001)have conducted an experimental study in which the effectiveness of theEDM process is evaluated in terms material removal rate (MRR), relative wear ratio (RWR) and surface roughnessof tungsten carbide which are functions of process variables such as electrode material, polarity, discharge current,* Corresponding author. Tel.: +919438480248; fax: +91-661-2462512.E-mail address: chinmaymohantymech@gmail.com2211-8128 © 2014 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/3.0/).Selection and peer review under responsibility of the Gokaraju Rangaraju Institute of Engineering and Technology (GRIET)doi:10.1016/j.mspro.2014.07.075606Chinmaya P. Mohanty et al. / Procedia Materials Science 6 (2014) 605 – 611open circuit voltage, pulse duration, pulse interval and flushing pressure. Habib (2009) has analyzed the effect ofmachining parameters such as current, gap voltage and pulse-on-time on MRR and TWR in EDM using responsesurface methodology where metal matrix composite Al/SiCp is machined with copper electrodes. Chattopadhyay etal. (2009) have used Taguchi’s design of experiment (DOE) method to conduct experiment on rotary EDM usingEN8 steel and copper as work piece-tool pair and proposed empirical relations between process responses andprocess variables such as peak current, pulse-on-time and rotational speed of tool electrode Dewangan and Biswas(2013) adopted for Taguchi experimental design for optimization of multiple responses, i.e., material removal rate(MRR) and tool wear rate (TWR) of electrical discharge machining (EDM) using AISI P20 tool steel as the workmaterial and copper electrode. Das et al. (2003) have suggested an EDM simulation model using finite element forcalculation of deformation, microstructure and residual stresses. Joshi and Pande (2009) have suggested a numeralmodel for EDM for precise and accurate prediction of process responses viz. material removal rate (MRR) and toolwear rate (TWR) using finite element method (FEM).NomenclatureΔWwweight of material removed from work pieceTmachining timeτduty factor in %Tonpulse-on-time (μs)Vopen circuit Voltage in VoltIpdischarge current (Amp)Fpflushing pressure (bar)Greek Symboldensity of work piecewLiterature review reveals, though number of attempts have been made until now to enhance the accuracy, utility andproductivity of the ...