Optimization of electric discharge machining parameters using composite tools for enhanced machining performance of aa7050 hybrid composites

Abstract

This research explores the machining performance of AA7050 hybrid newlinecomposites using Near-Dry Powder Mixed Electric Discharge Machining newline(NDEDM) with composite tool materials. The advanced manufacturing newlinetechniques such as Stir casting technique, Friction Stir processing etc. are newlineincorporated to fabricate the hybrid composites and composite tools. newlineReinforcements such as tungsten carbide (WC), silicon carbide (SiC), and newlineboron carbide (B4C) were incorporated into the aluminium matrix to enhance newlinemechanical properties, including wear resistance, thermal stability, and newlinehardness. Composite tools, comprising Cu - WC and AA6063 - WC, were newlinedeveloped to withstand the challenging conditions of NDEDM while ensuring newlineefficient energy transfer and minimal tool wear. The study examined the newlineinfluence of machining parameters, such as discharge current, pulse-on time, newlinepowder concentration, gap distance, Tool material and dielectric fluid on key newlineperformance metrics, including Material Removal Rate (MRR), Tool Wear newlineRate (TWR), and surface roughness (Ra). Experimental results revealed a newlinesignificant improvement in MRR with optimal Aland#8322;Oand#8323; powder concentration newline(2 g/L), which enhanced spark stability by increasing plasma channel newlineconductivity. However, at higher concentrations (3 g/L), the machining newlineprocess became unstable to debris accumulation and excessive heat newlinegeneration, adversely affecting surface integrity and TWR. Copper composite newlinetools out performed aluminium composite tools in terms of wear resistance newlineand surface finish, while aluminium tools provided slightly higher MRR to newlinebetter energy transfer efficiency. newline