ORIGINAL ARTICLE Multi response optimization of machining parameters of drilling Al/SiC metal matrix composite using grey relational analysis in the Taguchi method A. Noorul Haq & P. Marimuthu & R. Jeyapaul Received: 12 December 2006 / Accepted: 12 February 2007 / Published online: 10 March 2007 # Springer-Verlag London Limited 2007 Abstract This paper presents a new approach for the optimization of drilling parameters on drilling Al/SiC metal matrix composite with multiple responses based on orthog- onal array with grey relational analysis. Experiments are conducted on LM25-based aluminium alloy reinforced with green bonded silicon carbide of size 25 μm (10% volume fraction). Drilling tests are carried out using TiN coated HSS twist drills of 10 mm diameter under dry condition. In this study, drilling parameters namely cutting speed, feed and point angle are optimized with the considerations of multi responses such as surface roughness, cutting force and torque. A grey relational grade is obtained from the grey analysis. Based on the grey relational grade, optimum levels of parameters have been identified and significant contribution of parameters is determined by ANOVA. Confirmation test is conducted to validate the test result. Experimental results have shown that the responses in drilling process can be improved effectively through the new approach. Keywords Drilling . Al/SiC metal matrix composite . Orthogonal array . Grey relational analysis . ANOVA . Optimization 1 Introduction Metal matrix composites (MMC) are materials which combine tough metallic matrix with a hard ceramic reinforcement with superior properties like high strength to wear ratio, high modulus, superior wear resistance and corrosion resistance. These materials are widely used in various fields like aerospace, automotive, electronics and metallic industries and are very difficult to machine material due to the presence of hard ceramic particle [1–5]. Most of the researches on the machining of Al/SiC MMC have focused on turning and facing while drilling has received less attention. Davim [1] investigated the study of drilling metal matrix composites of type A356/20% SiC-T6 based on the Taguchi technique with the objective of establishing the correlations between cutting velocity, feed rate and cutting time with the evaluation of tool wear, the specific cutting pressure and the hole surface roughness using PCD drill. Tosun et al. [2, 3] investigated the effect of the various cutting parameters on the surface quality and microstructure on drilling of Al/17% SiC particulate MMC by using various drills. They have suggested that TiN coated HSS drills can be used for drilling Al/SiC-MMC rather than solid carbide tools. The quality of the drilled part is greatly influenced by the cutting conditions, tool geometry, tool material, machining process, chip formation, work piece material, tool wear, vibration during cutting, etc. Thus in material removal processes, improper selection of cutting conditions will result in rough surfaces [6]. Moreover, it is necessary to optimize the cutting parameters to obtain an extended tool life and better productivity, which are influenced by cutting force and torque [7]. Bhattacharyya [8] used the Lagrangian function method in searching for optimum cutting parameters. Ermer [9] used the geometric programming method. Lin [10] inves- Int J Adv Manuf Technol (2008) 37:250–255 DOI 10.1007/s00170-007-0981-4 A. N. Haq (*) : R. Jeyapaul Department of Production Engineering, National Institute of Technology, Tiruchirappalli 620 015, India e-mail: anhaq@nitt.edu R. Jeyapaul e-mail: jeyapaul@nitt.edu P. Marimuthu Department of Mechanical Engineering, Sona College of Technology, Salem 636 005, India e-mail: pmarimuthu69@gmail.com