Robust Parameters Design and Optimization of an Underwater Nd:YAG Laser Microchanneling Process Using the Taguchi Method

Nd:YAG lasers are widely used in metal cutting industries; however, they have not yet been fully exploited in creating micro-features on samples because of high heat affected zone (HAZ) and uncontrolled material removal. In this work a Nd: YAG laser has been utilized in creating microchannels on polymethylmethacrylate (PMMA) in submerged water condition. Taguchi methodology with L-16 orthogonal array design has been chosen for performing the experiments. Lamp current, scanning speed, pulse frequency and pulse width has been selected as input process parameters. Width and depth of the microchannels have been taken as output quality characteristics. Analysis of variance has been performed for each quality characteristics to check the compatibility of this methodology. Each quality characteristics has been optimized using Taguchi's technique. Multiple quality characteristics have been optimized using grey based Taguchi technique. Grey based Taguchi technique provides efficient and effective way to optimize the process based on grey relational grades. Underwater laser processing resulted in lowering heat affected zone (HAZ) and debris formation therefore producing clean structures than air. Experiments showed that the process can be readily used in micromachining facilities to create micro-features on materials.