YAG Laser Spot Welding of PET and Metallic Materials

Dissimilar materials joint has a great interest in industrial applications including automotives, aircrafts, medical, electronic industry, etc. Moreover, the combination of plastics and metals in the product would cater advantages in specific engineering application. In this study, direct joining using YAG laser spot welding for dissimilar materials joint between plastic and metallic materials has been investigated. Experimental result showed polyethylene terephthalate (PET) could be successfully joined to aluminum alloy (A5052), stainless steel (SUS 304) and copper (Cu). Shear tensile test was carried out to evaluate the joining strength. In the case of PET/Cu joint, the joining strength was almost constant regardless of heat input. However, the strength increased with increasing heat input for PET/A5052 and PET/SUS304 joints. Cross-sectional observation of the joined specimen showed no significant molten pool in the case of PET/Cu joint. On the other hand, an obvious weld pool was observed at the interface in metallic material side for PET/A5052 and PET/SUS304 joints. Differences of morphology at the interface would result from different material properties, such as reflectivity and absorptivity of laser, thermal conductivity, etc., of metallic materials used and might affect the joining strength.