Title: Experimental investigation of MRR on in situ formed AA7075/TiB₂ cast composites machining by wire EDM

Authors: S. Ramabalan; H.B. Michael Rajan; I. Dinaharan; S.J. Vijay

Addresses: Department of Mechanical Engineering, EGS Pillay Engineering College, Nagapattinam – 611002, Tamil Nadu, India ' Department of Mechanical Engineering, SAMS College of Engineering, and Technology, Periyapalayam, Chennai – 601102, Tamil Nadu, India ' Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg 2006, South Africa ' School of Mechanical Sciences, Karunya University, Coimbatore – 641114, Tamil Nadu, India

Abstract: This paper presents the effects of different input machining parameters (pulse-on time, pulse-off time, peak current, wire feed) and the amount of reinforcement (0, 3, 6 and 9 wt% of TiB₂) on material removal rate (MRR) of AA7075/TiB₂ in situ metal matrix composites. The L₉ orthogonal arrays of Taguchi, the signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) were employed to find the optimal process parameter levels and to analyse the effect of these parameters on material removal rate (MRR). Experimental results show that the unreinforced AA7075 exhibits higher MRR than the AA7075/TiB₂ composites. The average machining speed of the composite was found to be decreasing with increased %wt of TiB₂ reinforcement. Confirmation test with the optimal levels of machining parameters was carried out in order to illustrate the effectiveness of the Taguchi optimisation method.

Keywords: wire EDM; MMC; metal matrix composites; material removal rate; MRR; aluminium matrix composites; AMCs; in situ casting; TiB2 reinforcement; titanium diboride; pulse-on time; pulse-off time; peak current; wire feed; orthogonal arrays; Taguchi methods; machining speed; electrical discharge machining; electro-discharge machining.

DOI: 10.1504/IJMMM.2015.072001

International Journal of Machining and Machinability of Materials, 2015 Vol.17 No.3/4, pp.295 - 318

Received: 09 Dec 2014
Accepted: 21 Mar 2015
Published online: 27 Sep 2015 *

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