Experimental Modeling and Process Optimization of Laser Transmission Welding with Fiber Optic Laser for Polymethyl Methacrylate in Zigzag Path

Abstract This study experimentally evaluated Laser Transmission Welding (LTW) between two transparent and identical Polymethyl Methacrylate (PMMA) sheets using a fiber optic laser following a zigzag path. The research focused on the effects of laser power, welding speed, and distance between scan lines on lap-shear force, weld-seam width, and changes in weld morphology. Pyrometry was used to measure the welding temperature and determine input parameters. Analysis of Variance (ANOVA) and Response Surface Methodology (RSM) were employed to analyze and optimize the input parameters for maximum lap-shear force and minimal weld-seam width. The findings indicated that higher laser power, slower welding speed, and a reduced distance between scan lines increased heat input, leading to enhanced polymer melting and improved weld strength, reflected by higher lap-shear force and broader weld-seam width. Conversely, lower heat input decreased both lap-shear force and weld-seam width. Optimal values for lap-shear force and weld-seam width were determined to be 886.4 N and 26.37 mm, respectively, through multi-objective optimization. The zigzag welding path contributed to uniform heat distribution, even mixing of melted materials, and better structural integrity in the weld zone. Morphological analysis revealed that the weld strength was enhanced due to the presence of smaller, evenly distributed bubbles in the weld pool, attributed to the zigzag path. These findings highlight the significance of controlling welding parameters to optimize strength and seam quality in laser transmission welding of PMMA.