Title: Effect of SiC powder-suspended dielectric fluid on the surface finish of 6061Al/Al₂O_3P/20p composites during electric discharge machining

Authors: Shankar Singh, Sachin Maheshwari, Poorn Chandra Pandey

Addresses: Department of Mechanical Engineering, Sant Longowal Institute of Engineering and Technology, Deemed-to-be-University, Sangrur Punjab 148106, India. ' Netaji Subhas Institute of Technology, Division of Manufacturing Processes and Automation Engineering (MPAE), Dwarka, New Delhi 110 078, India. ' Department of Production and Industrial Engineering, Indian Institute of Technology, Roorkee, Roorkee, UA 247667, India

Abstract: Electrical Discharge Machining (EDM), one of the most widely used unconventional machining processes particularly for producing complex shapes on hard materials with high geometrical and dimensional accuracy. The work material surface obtained after EDM is characterised by a series of randomly laid out tiny craters produced by the high energy spark discharges and recast (white) layer formed due to resolidification and deposition of materials ejected from the craters. This requires some form of supplementary finishing operations. This paper presents the results obtained from a comparative machinability study carried out on stir-casted 6061Al/Al₂O_3P/20p work specimens with copper electrode tools by using plain dielectric fluid and Silicon Carbide (SiC) abrasive powder-suspended dielectric fluid and evaluating the machinability in terms of Surface Roughness (SR). The results of both the processes have been analysed using Lenth|s method to find the significant parameters and obtaining optimum machining parameter settings. It was found experimentally that Abrasive Particle Size (APS); Abrasive Particle Concentration (APC) and pulse current are the most significant parameters that affect the surface characteristics.

Keywords: AMMCs; aluminium MMCs; metal matrix composites; EDM; electrical discharge machining; electro-discharge machining; AEDM; abrasive EDM; abrasive powder suspension; surface finish; abrasive particle size; abrasive particle concentration; aspect ratio; pulse current; pulse ON time; silicon carbide; surface roughness; machinability.

DOI: 10.1504/IJMMM.2008.023196

International Journal of Machining and Machinability of Materials, 2008 Vol.4 No.2/3, pp.252 - 274

Published online: 13 Feb 2009 *

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