Continuous carbon and glass fibre reinforced composite materials (thermoplastic or thermoset) are widely recognized as having significant potential for lightweight structures in many industrial sectors. One barrier to the widespread uptake of thermoplastic composites (TPC) structures is the lack of economic, quick and reliable component manufacturing processes that includes joining technologies. Different joining techniques such as resistance welding, ultrasonic welding, vibration welding or induction welding are used, revealing respective advantages and disadvantages.
The aim of the European Eurostars project LaWocs (“Laser transmission welding of thermoplastic composite structures”) was to develop a novel joining technique for TPC parts based on laser transmission welding (LTW) technology. Laser transmission welding is an industrially established welding technique for unreinforced and short fiber reinforced thermoplastics.
Within the framework of the project, this technology was transferred to the specific requirements of long fibre reinforced TPC materials. Demonstrator parts and materials were mainly realized for aerospace applications. This welding method has provided the possibility to join thermoplastic brackets, retainers and pins to larger components made of CFRP without adhesive bonding or riveting. Larger structures were also realized, welded and tested within the project. It emerged very clear that laser transmission welding of TPC offers a highly flexible and automatable process with short cycle times and with reduced manufacturing steps.