Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 24 (2020) 218–224 www.materialstoday.com/proceedings * Corresponding author. Tel.: +91-9583640120 E-mail address: rahulkumar589@gmail.com 2214-7853© 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Materials and Manufacturing Applications [IConAMMA 2017]. IConAMMA_2018 Optimization of Surface Topography of Electro- Discharge Machined Super Alloy Inconel 825: Using TOPSIS Integrated with Taguchi Philosophy Shishir Raj a , Rahul b *, Himanshu Ranjan Sinha c , Shivani d , Shuvam Das e , Shreetanu Guha f , Aazim g , Dipraj Banik h , B.C Routara i a,b,c,d,e,f,g,h,i School of Mechanical Engineering,KIIT Deemed to be University,Bhubaneswar,751024, Odisha, India Abstract The aim of this research work is to find the optimum combination of input process parameters such as Peak Current(I P ), Open Voltage(V g ), Pulse-On-Time(T on ) & Duty Factor(τ) for machining of Inconel 825 on EDM using copper electrode. The experiment has been designed on 4 levels 4 factors i.e. L 16 orthogonal array. The output response parameters studied were Metal Removal Rate (MRR), Electrode Wear Rate (EWR) and Surface Roughness (R a ). During our study we have used Taguchi method to identify the proper control factors to obtain the optimum results of the process. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Materials and Manufacturing Applications [IConAMMA 2017]. Keywords:EDM; Inconel 825; Copper Electrode; Topsis method; Taguchi Philosophy. 1. Introduction Electro Discharge Machine is one of the most significant and remarkable technology. Both the Tool and Electrolyte when placed in a dielectric medium and a very high Electric potential is applied, a high impulse electric spark is generated. The spark dissipates a huge amount of heat (8000°C to 12000°C) as a result melts the work piece. Then it vaporizes in the discharge column due to ionization and a flushing pressure imparted on the workpiece by the pumped dielectric fluid. We have used a copper electrode during machining which produces low tool wear rate. Inconel 825 is an alloy which is highly resistant to corrosion and it contains additions of molybdenum, copper & titanium. Typical applications of Inconel 825 include propeller shaft, Tank Trucks, Calorifiers etc. As Inconel 825 is