Performance optimization of electric discharge machine process parameters for machining Inconel 718

Abstract

Electrical Discharge Machine EDM has a one off significant process for machining of hard materials and super alloys Heat Resistant Super Alloys HRSA especially Inconel alloy finds applications in aerospace and marine components cryogenic storage tanks and nuclear reactor components Based on the literatures the characteristics of Electrical Discharge Machine for machining holes on Inconel 718 are influenced by various input parameters Each performance characteristic has different optimal process parameters combination and hence in case of multiple responses the selections of optimal machining parameters are difficult The Grey system proposed by Deng handles the vague information and hence Grey Relational Analysis GRA method is recommended as a principal method for multiple response optimisation In this paper EDM process parameters: Current I Voltage V Pulse on time ton and Pulse off time toff were optimized through the L18 orthogonal experimental design method and the Grey Relational Analysis GRA method considering multi responses such as machining rate MR tool wear rate TWR overcut OC and taper overcut TOC Using Grey Taguchi and Technique for order preference by similarity to an ideal solution TOPSIS method not much work has been done although these methods can be easily applied for multi objective optimization The significant contribution of this research is in using these methods to study the influential parameters that provide best results with the available sparse data Based on Grey Relational Analysis GRA and Technique for order preference by similarity to an ideal solution TOPSIS the optimum level parameters for Electrical Discharge Machine EDM have been identified Further the tool wear behaviour is also studied through Scanning Electron Microscope SEM images by varying the voltage newline