Laser transmission welding of polycarbonate sheets using electrolytic iron powder absorber

Abstract

This paper presents Laser Transmission Welding (LTW) of polycarbonate sheets using electrolytic iron powder as an absorber to obtain a clean and high-strength joint without any gap between the sheets. Surface temperature is measured to analyze the bubble morphology and relate them with the heat absorbed at the interface. The lap shear test is performed to evaluate the weld strength, and fracture modes of the welded joints. The results show that maximum weld strength is achieved with smaller bubbles. Scanning electron microscope (SEM) micrograph of the fractured surface shows micro-fibrils at the inter-bubble space, enhancing the weld strength. The iron particles present inside the bubble increase the size of the bubbles, and the presence of cleavage facets reveals the brittle failure of the joint. The weld joints are fractured mainly by interfacial and substrate fractures. The optimum process parameters are obtained using a genetic algorithm (GA), and the confirmation test shows an improvement of 36.32 % in weld strength compared with Taguchi parameters.