ORIGINAL ARTICLE Robust parameter design and multi-objective optimization of laser beam cutting for aluminium alloy sheet Avanish Kumar Dubey & Vinod Yadava Received: 31 December 2006 / Accepted: 21 May 2007 / Published online: 7 July 2007 # Springer-Verlag London Limited 2007 Abstract The application of laser beam for precise cutting of sheet metals, in general, and reflective sheet metals, like aluminium, in particular, has become of interest in the recent past. The optimum choice of the cutting parameters is essential for the economic and efficient cutting of difficult to cut materials with laser beams. In this paper, a robust design and quality optimization tool called the Taguchi methodology has been applied to find the optimal cutting parameters for cutting of a reflective sheet made of aluminium alloy with a Nd:YAG laser beam. All the steps of the Taguchi method, such as a selection of orthogonal array, computation of signal-to-noise ratio, decision of optimum setting of parameters, and the analysis of variance (ANOVA), have been done by a self-developed software called computer aided robust parameter design (CARPD). A considerable improvement in the kerf taper (KT) and material removal rate (MRR) has been found by using Taguchi method-based predicted results. Confirmatory experimental results have shown good agreement with predicted results. Further, the Taguchi quality loss function has also been used for multi-objective optimization of laser beam cutting of Al-alloy sheet. The results of multi-objective optimization are compared with the single-objective optimi- zation and it has been found that the kerf taper was increased by 1.60% in multi-objective optimization while the MRR was same in both cases. Keywords Laser beam cutting . Taguchi methodology . Nd:YAG . Kerf taper . MRR . Multi-objective optimization Abbreviations k no. of control factors or process parameters L j the total normalised quality loss for j th trial condition or run l ij quality loss value in i th experimental run for j th quality characteristic l i* maximum quality loss for the i th quality characteristic among all the experimental runs b l ij normalized quality loss value in i th experimental run for j th quality characteristic n no. of experimental runs p no. of responses or quality characteristics w i weighting factor assigned to i th response or quality characteristic y i response or observed quality value in i th experimental run η S/N ratio h mean value of S/N ratios of all experimental runs η opt predicted S/N ratio at optimum parameter levels η mi average S/N ratio corresponding to i th control factor at optimum level h e j multiple S/N ratio of j th trial condition or experimental run 1 Introduction Laser source energy is a major innovative form of energy used for shaping engineering materials with complex shapes and stringent design requirements. The laser beams are widely used for cutting, drilling, marking, welding, sintering and heat treatment. Lasers can also be used to perform turning and milling operations. Major application of laser beam is mainly in cutting of sheets made of metals Int J Adv Manuf Technol (2008) 38:268–277 DOI 10.1007/s00170-007-1105-x A. K. Dubey : V. Yadava (*) Department of Mechanical Engineering, Motilal Nehru National Institute of Technology, Allahabad 211004, India e-mail: vinody@mnnit.ac.in