Experimental investigation of wire EDM parameters during machining of fabricated hybrid Al/(SiC+ZrO2+NiTi)-MMC

Abstract

ABSTRACT Nowadays, advanced engineering materials are gradually becoming more attractive to the industries because of their high fatigue strength, hardness, thermal shock resistance, attractive strength to weight ratio, etc. Aluminium metal matrix composites (MMCs) have such properties and good electrical conductivity. Therefore, wire electrical discharge machining (WEDM) was found to be a suitable process for machining of such materials. The open gap voltage, pulse-on-time, pulse-off-time, peak current, wire feed rate and wire tension were considered as input process parameters, and experiments were carried out on fabricated hybrid Al/(SiC+ZrO2+ NiTi)-MMC. Taguchi method-based L18 (21x37) mixed orthogonal array was employed for planning of experiments. The process parameters were optimised for material removal rate (MRR) and surface roughness (SR) heights. Confirmation results reveals 61.88%, −28.75% and −20.25% improvement in MRR, Ra and Rt respectively, over initial setting. From analysis of variance (ANOVA), open gap voltage and pulse-on-time were found significant parameters for MRR and SR. The mathematical models for MRR and SR were developed and confirmation test reveals good agreement of it with experimental results. Scanning electron microscopy images reveal that the recast layer thickness was 8.569 µm at optimal MRR setting and 6.113 µm at optimal surface roughness (Ra) setting.