An Initial Study of the effect of Minimum Quantity Lubricant of SiO 2 Nanoparticle with PEG on Surface Roughness during Milling of Mild Steel A.N.M Khalil 1,a , A.I.Azmi ,b ,M.A.M Ali ,c 1 School of Manufacturing Engineering, University Malaysia Perlis, Malaysia a nabilkhalil@unimap.edu.my, b azwaniskandar@unimap.edu.my, c acap.rave@gmail.com Keywords: MQL, Nanolubricant, Taguchi L9, Machining Abstract. This paper studies the effect of minimum quantity lubricant of SiO 2 nanoparticle with surfactant, PEG on surface roughness during machining of mild steel. The application of conventional cutting fluid leads to techno-environmental issue such as environmental pollution. Nanolubricant consists of suspended nanoparticles in base fluid. Nanolubricant with surfactant creates stability of the particles in the base fluid. The results indicate the application of minimum quantity lubricant of nanolubricant with surfactant during machining process lead to minimum usage of cutting fluid and better surface finish. Introduction In recent years, environmental issues such as reduction of environmental pollution, promoting the quality of life and elimination of impurities are of high importance in developed countries. It is a well-known fact that extensive and overuse of lubricants in metal working industries to prolong the life of mechanical tools, improve surface finish, and slow down tool wear and to reduce friction [1], greatly contributes to environmental pollution. Recent studies on lubricants with additives such as nano-particles that have attracted the interest of many researchers may hold the promising answers to addressing this issue. Polytetrafluoroethene, graphite, and molybdenum disulphide are the most common commercial particles employed as additives in this type of lubricant [2]. These base fluids suspended with nano-meter sized particles referred to as nanolubricant, improves lubrication performance by averting contact between metal surfaces. Moreover, the thermal conductivity of a nanolubricant increases linearly with the concentration, thus facilitating hydrodynamic interaction to enhance thermal transport capability and improved heat carrying capacity, anti-wear and friction reduction properties [3]–[5]. It has been reported that the suspended nanoparticle in base oil leads to agglomeration after some period of time. Thus, it is necessary to study and analyze the influencing factors to the dispersion stability of nanofluids [6], [7]. Surfactants are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids. It increases the solubility, mobility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds [8]. Nanolubricant with surfactant has been shown to yield better results in terms of stability, thermal conductivity and fluid viscosity [9]–[10]. Several recent studies however, mainly focus on the advantages of the use of nanolubricants on the performance of machining operations. Fundamental understanding of the effects of nanolubricant with surfactant on the quality of machined surfaces is inadequate. Hence, in this study, the optimal operating condition employing minimum quantity nanolubricant with surfactant to improve surface finish is proposed. Minimum quantity lubrication (MQL), also known as near dry machining (NDM), refers to the use of cutting fluids in tiny quantities, which is only about ten-thousandth of the amount of cutting fluid used in flood-cooled machining. Applied Mechanics and Materials Vol. 695 (2015) pp 627-630 Submitted: 01.09.2014 © (2015) Trans Tech Publications, Switzerland Revised: 13.09.2014 doi:10.4028/www.scientific.net/AMM.695.627 Accepted: 13.09.2014 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 115.135.224.52-31/10/14,12:00:45)