Ultrasonic welding of composite laminate GF/PA6: Weldability and weld quality by current and strength

Ultrasonic welding (USW) of thermoplastic composites is considered as an interesting joint technique, which can be cost-effective due to its short welding time. The paper focuses on studying the effect of USW current on strength and quality of welding. In this paper, the welding of thermoplastic unidirectional prepregs glass/polyamide 6 composites laminate with stacking sequence of (0/90/+45/−45/−45/+45/90/0) is conducted by USW. A flat energy director is used to concentrate the interface heat. To examine the interface microstructure, the current-time graph was utilized during welding processes, and the relationship between such interface events, consumed current, weld strength, weldability, and weld quality is fully investigated. Based on the results, the highest welding strength and welding quality of thermoplastic composites can be obtained when the energy director and the first layer of the composite are completely melted and no disorder is observed in the fibers. In addition, the highest joint strength equals to 24.46 MPa, which is obtained after 1830 ms welding time.