SURFACE TOPOGRAPHY AND MORPHOLOGICAL STUDY OPTIMIZATION OF EDMED WORK SURFACE OF INCONEL 601 OBTAINED USING SOLID CYLINDRICAL CROSS-SECTIONED COPPER TOOL ELECTRODE

Abstract

Inconel alloy has been a solution to diverse fields where automobile industry, aircraft, nuclear reactor are the foremost and major applicants of Inconel alloy. But the aim is precise manufacturing in minimum time. Inconel is known for its hard to machine characteristic. This paper illustrates the machining effect on Inconel 601 in EDM. Electrode discharge machining with its ability to machine hard conductive metals is the most recognized and suitable nonconventional machine for the purpose. Experiments with four level of variation and five parameters, (that is, OCV, peak current, pulse on time, duty factor and flushing pressure) have been conducted in 16 different combinations under L16 orthogonal array. Metal removal rate (MRR), surface roughness ($R_a$), surface crack density (SCD), and white layer thickness (WLT) have been calculated herein. Surface roughness has been depicted with the help of Taylor Hobson materialize finishing tester. The view of the fact that conventional Taguchi technique cannot be used to solve the multiple response optimization problem independently, so TOPSIS method has been used in this paper to convert multiple responses into an aggregated performance index (called closeness coefficient $C_i^{+}$) which has been optimized finally by the Taguchi technique. In this, MRR and Ra have been optimized by using the TOPSIS technique and it is found that by using optimal setting i.e. A₄B₁C₂D₁E${}_{2,}$ MRR will be higher while Ra will be lower. Moreover, micro-graphical studies have been conducted to analyze various surface irregularities (SCD and WLT) of EDMed Inconel 601. SCD and WLT have been investigated with respect to optimal settings (A₄B₁C₂D₁E₂) and obituary settings run no. 10 (A₃B₂C₄D₃E₁) and better results have been obtained in optimal settings as compared to obituary settings.