Effect of ultrasonic welding process on the crystallinity at the welding interface of CF/PPS joints

The influence of the ultrasonic welding process parameters, namely the force and the vibration amplitude, on the crystallinity degree at the welding interface of CF/PPS (carbon fibre reinforced poly(phenylene) sulphide) joints is investigated. Two different sets of parameters, one representing high force and high vibration amplitude (1000 N,...

Ultrasonic welding of CF/epoxy to CF/PEEK composites: Effect of the energy director material on the welding process

With its short heating times, ultrasonic welding is a highly promising technique for joining thermoplastic (TPC) to thermoset (TSC) composites, to prevent thermal degradation of the thermoset adherend. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the TSC “weldable”. For welding CF/PEEK to a TSC adherend,...

Multi-spot ultrasonic welding of thermoplastic composite single-lap joints: Effect of spot spacing and number of spots on weld strength

Thermoplastic composite spot welded joints are more well-suited for carrying shear load rather than peel load. However, peel load is difficult to be eliminated in single-lap joint configuration. In this paper, a series of mechanical tests were carried out to study the effects of the spot spacing and the number of welded spots on the secondary...

Investigation on the melting of the weld interface in continuous ultrasonic welding of thermoplastic composites

Continuous ultrasonic welding is a new promising high-speed joining technique for thermoplastic composites. At the moment no straightforward method exists to find an optimum welding speed to easily obtain high strength joints. However, for static ultrasonic welding a systematic approach is available. Therefore, the aim of this study is to...

A Roadmap for developing an Industrial Continuous Ultrasonic Welding Process for Thermoplastic Composites

The increasing use of fibre-reinforced plastics in the aerospace industry leads to challenges in joining these materials. The traditionally used mechanical fasteners introduce damage when used in composites by disrupting the fibres. However, thermoplastic composites allow for fusion bonding processes to join parts. Ultrasonic welding has shown...

Towards high-quality multi-spot-welded joints in thermoplastic composite structures

Ultrasonic welding is a promising assembly technique for thermoplastic composites and it is well-suited for spot welding. In this study, two typical welding process control strategies, i.e. displacement-controlled and energy-controlled welding, were selected to manufacture spot-welded joints. The influence of different boundary conditions,...