flexibility, accuracy, ease of automation and reproducibility as compared to other conventional marking techniques such as hot stamping, mechanical scribing or inkjet [i]. The non-contact nature of the process allows wide variety of materials such as plastics, wood, metal and ceramics to be used as work piece that furthers the usefulness of the process [ii, iv]. The principle of operation is based on ablation wherein the interaction between material and the laser beam, which comes from a laser system and passes through a focusing lens (convex lens), leads to the vaporization and melting of work material. As a result, the material is removed from the work piece in layers via ablation mechanism [i, v]. Fig. 1 shows the principle of operation for a laser marking machine. Fig. 1. Principle of operation for a laser marking machine [i] Several studies have been done on the parametric optimization in order to improve the quality of marked parts [v-x]. Results of these studies show that process parameters can be adjusted to optimize the process for number of applications. Some researchers [vii] have used Artificial Neural Networking (ANN) while optimizing the process whereas others have used Taguchi method to improve the quality of marked parts [v]. No considerable work, however, could be found for the optimization for marking time. Considering, that the marking time is related to the cost dynamics of the process it is imperative that a study is undertaken to 49 Abstract-This paper parametrically optimizes the laser marking process for marking stainless steel AISI 316L for marking's quality and time using Taguchi method wherein the rationale is to ensure the compatibility of the process with material being processed. Four parameters namely “laser frequency”, “number of layers removed”, “laser power” and “scanning speed” are investigated herein. Main effect for means and signal to noise ratio have been done to study & optimize the effects of variables on stated performance measures respectively. The process is mathematically formulated via linear regression model. It is found that among the factors studied herein, major contributing factor for marking time is “number of layers removed” whereas “scanning speed” effects surface roughness the most. Optimum levels for minimizing marking time are determined to be: level 1 for “laser frequency” and “number of layers removed”, level 2 for “laser power” and level 3 for “scanning speed”. On the other hand, for minimization of surface roughness, optimum levels are found to be: level 1 for “laser frequency”, “number of layers removed” and “laser power” and level 3 for “scanning speed”. The mathematical model developed herein is found to be statistically significant at 95% confidence level with contributions of model terms to be 98.92% for marking time and 96.84% for surface roughness. The developed models are validated by the confirmatory run wherein good agreement between predicted and experimental values is obtained. Keywords-Laser Marking, Taguchi Method, Surface Roughness .INTRODUCTION Laser beam marking process uses a highly focused laser light that falls on the surface of the work part to engrave or mark the object. The process has wide applications in various types of food industries for engraving number and dates on food packages as well as for marking and printing logos and bar codes on printed circuit boards, electronic components and other products for the purpose of product identification and traceability [i-iii]. The process provides higher I Technical Journal, University of Engineering and Technology (UET) Taxila, Pakistan Vol. 20 No. II-2015 Parametric Optimization for Laser Marking Performance via Taguchi Approach 1 2 3 A. R. Khan , M. Q. Saleem , A. Ikram 1 Industrial & Manufacturing Engineering Department, Rachna College of Engineering & Technology (Constituent College of University of Engineering & Technology, Lahore) Gujranwala, Pakistan 2 Industrial & Manufacturing Engineering Department, University of Engineering & Technology Lahore, Pakistan 3 Engineering Department, University of Gujrat, Gujrat, Pakistan 2 qaiser@uet.edu.pk