Effect of Molten Pool Shape on Tensile Shear Strength of Dissimilar Materials Laser Spot Joint between Plastic and Metal

Dissimilar materials laser spot joining between polyethylene terephthalate (PET) and aluminum alloy (A5052) was studied by using pulse YAG laser. The results showed that it was possible to make a joint in a wide range of heat input. Molten pool was formed at the interface of A5052 and the depth of molten pool increased with an increase in heat input. Tensile shear test was carried out to evaluate strength of the joints. The result showed that tensile shear strength increased with an increase in the heat input when the molten pool filled with molten or softened PET. On the other hand, instability of joining state inside the molten pool might induce variation in the strength. FEM analysis was carried out to investigate the effect of molten pool shape on the strength. The result showed that molten pool radius did not significantly affect tensile shear strength.