Fabrication of Micro Channels Using Wire EDM for Optimum Process Parameter using MADAM - TOPSIS Approach

Abstract

Wire Electric Discharge (WEDM) Machining is using for fabrication of micro channels. Wire EDM is time consuming, stochastic and highly complex process. That's why optimum input parameters are required which count on user's technology and experience because of their large diverse and abundant range. In Wire EDM high precision cutting operations are challenging because of more than one responses are taken into account as Material Removal Rate (MRR), Surface Roughness (Ra) and Wire wear ratio (WRR). Aluminum (6061) Work Piece is used for micro channels fabrication. Micro channels of 1mm depth, 0.5mm width are fabricated on Al (6061) work piece of 30mm×30mm for fabrication process parameters taken which are varied in different range as Pulse On Time Ton (105-125 μsec), Servo Voltage (30-90V) and Wire Feed Rate (6-8 mm/min).Material Removal Rate (MRR), Surface Roughness (Ra) and Wire Wear Ratio (WRR) are estimated for micro channels performance. These process parameters and response parameters are co related with the help of Response Surface Methodology (RSM).In Response surface methodology using MINITAB 17.0 software experiment is designed for experimental runs. Using Response Surface Methodology using MINITAB gives 20 experimental runs for different values combination of process parameters of Pulse on Time (Ton), Servo Voltage and Wire Feed Rate .Using Wire EDM Micro channels are fabricated based upon these designed experimental runs. Response parameters are measured corresponding to these 20 experimental runs. Surface Roughness (Ra) is measured with the help of Mitutoyo SJ 400 profilometer.Three Mathematical Equations are produced between process parameters and response parameters which helps to explain the variations in responses with the variations in input or process parameters using MINITAB software. After that we engender the surface plots and contour plots to see the effect of combination of two process parameters on response parameter. Then Main Effects Plots and Residual plots are plotted with MINITAB to examine the individual process parameter effect on responses. It has been concluded that Pulse On Time is most dominant factor in Material Removal Rate (MRR).And Servo Voltage effects the surface roughness (Ra).After the Experimentation and Mathematical Modeling next step is optimization, selection, evaluation and ranking for optimum parameter setting of process having Higher [iv] Material Removal Rate (MRR), Lower Surface Roughness and Wire Wear Ratio is done with MADM (Multiple Attribute Decision Making) Approach. Identification of Pertinent Attributes and Ranking is done with help of TOPSIS (Technique for order preferences by similarity to ideal solution).Optimum process parameters setting is obtained for Maximum Material Removal Rate (MRR), Minimum Surface Roughness (Ra) and Wire Wear Ratio (WRR) explained with illustrative example.