The effect of Laser-Induced deconsolidation on the compaction behavior of thermoplastic composite tapes

The effects of laser-induced deconsolidation on the compaction process of CF/PEEK tapes were investigated. First, tapes with different degrees of deconsolidation were manufactured using a laser heater. This procedure resulted in samples with different waviness, thickness, void content and surface roughness values. Then, as-received and laser...

Deconsolidation of thermoplastic prepreg tapes during rapid laser heating

In this study, the effect of rapid laser heating, which is typical during laser-assisted fiber placement (LAFP), on the micro- and meso- structure of the thermoplastic tape was investigated. Thermoplastic tapes were heated above the melting temperature with different heated lengths (30 and 80 mm and heating times (0.2 and 0.8 s) in a dedicated...

The influence of inter-laminar thermal contact resistance on the cooling of material during laser assisted fiber placement

The effect of thermal contact resistance (TCR) correlated to the degree of intimate contact (DIC) between the incoming tape and the substrate on the temperature history during laser-assisted fiber placement (LAFP) was investigated. A novel experimental methodology was designed to understand the effect with a non-contact method which did not...

On differences and similarities between static and continuous ultrasonic welding of thermoplastic composites

Continuous ultrasonic welding is a promising high-speed and energy-efficient joining method for thermoplastic composite structures. Our aim was to identify and understand differences between the static and continuous ultrasonic welding process for thermoplastic composites. In particular, melting of the interface, consumed power and energy...

Intimate contact development during laser assisted fiber placement: Microstructure and effect of process parameters

Intimate contact development under LAFP-specific thermal and mechanical boundary conditions/interactions and the effect of process parameters are investigated. One-layer, unidirectional strips of CF/PEKK material were placed with different process parameters on a flat tool surface to create different intimate contact conditions. The concept...

Continuous ultrasonic welding of thermoplastic composites: Enhancing the weld uniformity by changing the energy director

Continuous ultrasonic welding is a high-speed joining method for thermoplastic composites. Currently, a thin film energy director is used to focus the heat generation at the interface. However, areas of intact energy director remain in the welded seam, which significantly lowers the weld strength, and result in a non-uniformly welded seam. To...

Improving weld uniformity in continuous ultrasonic welding of thermoplastic composites

Continuous ultrasonic welding (CUW) is an innovative high-speed joining method for thermoplastic composites. Currently, thin flat energy directors (EDs) are used to focus the heat generation at the weld line. The resulting fracture surfaces exhibit large areas of intact ED, resulting in a non-uniform weld, and significantly lowering the strength...