Optimization and prediction of response characteristics of electrical discharge machining using AHP-MOORA and RSM

Electrical Discharge Machining (EDM) is one of the advanced machining processes which is used to generate very complicated and detailed shapes. The materials which can be machined using this process must be electrically conductive and should be highly resistant as well as high strength metal alloys. For obtaining the best response outcomes, it is important to perform optimization of input parameters like pulse current, pulse on time, pulse off time, gap voltage, discharge energy, discharge current, peak current, etc. for response features viz. material removal rate (MRR), gap size (GS), surface roughness (SR), tool wear ratio (TWR) of EDM. It is important to consider a greater number of input parameters for better result. For optimization of EDM parameters, there are a number of techniques that can be used. Analytical Hierarchy Process (AHP) is a decision-making method and Multi Objective Optimization by Ratio Analysis (MOORA) is a technique encompassing both minimization and maximization criterions for the selection of proper alternatives. Response Surface Methodology (RSM) is a technique based on the collection of tools, both mathematical and statistical that are useful for modelling and analysing of engineering problems. In this work, AHP and MOORA has been combined and implemented to optimize the results. The experimental values have been taken from literature. Also, RSM has been used in this study for predicting the responses and the results are compared. In the AHP-MOORA method, the experiment number 20 results in the best alternative. Further, the RSM has been used on the optimum results obtained from the AHP-MOORA method to predict the outputs. The input parameters viz. pulse current of 30 amp, pulse on time of 150 μs, gap voltage of 34 Volt and SiC concentration of 10 % yielded the best optimal values of MRR, TWR, SR and GS. Additionally, the MRR, TWR, GS and SR deviated 0.17 %, 0.39 %, 0.51 % and 2.73 % respectively with regard to the optimum values from the AHP-MOORA and RSM methods. It has been observed that the deviation is less, therefore we can use MOORA method for faster result and less mathematical calculations as compared to RSM.