Study of the ultrasonic welding of a polycarbonate-glass fiber laminate and comparison with adhesive bonding

This work is aimed at exploring the feasibility of ultrasonic welding (USW) of a composite laminate made of polycarbonate reinforced with continuous glass fibers, with and without the addition of an energy director (ED) in the form of a neat polycarbonate wire. Welding has been done by varying one factor at a time in order to highlight the dependence of joint strength on each welding parameter. The material has been tested with dynamic mechanical analysis in order to characterize the viscoelastic behavior and temperature dependence. The results in terms of strength show that it is possible to weld also without an ED, but the results using this latter are much better in terms of both average value and standard deviation. The USW joint strength has also been compared with that of adhesive joints, resulting better than this latter when employing the ED, which makes USW a convenient technology for joining this type of composite material.