Visual inspection of pulsed Nd: YAG laser welding of PMMA and stainless steel 304

This paper reports an experimental study of welding of dissimilar materials between transparent Polymethyl methacrylae (PMMA) and stainless steel 304 sheets using a pulsed mode Nd: YAG laser. Compared with other methods, laser joining could achieve a clean weld and heat up materials. The light and process were represented by laser peak power, welding speed, spot diameter, pulse width, pulse frequency and argon gas flow rate, and these experiment parameters have a significant effect on the joint strength, weld width, joint quality and appearance. The welding parameters were optimized by orthogonal experiment design. The appearance of weld seams was observed by metallographic microscope. The weldment was subjected to lap-shear test by means of the electronic universal testing machine, and the quality of the weldment was judged by visual observation.