Beschreibung
This work presents a novel concept for the in-situ production of thermoplastic sandwich structures using laser-based thermoplastic automated fiber placement (TAFP). Thermoplastic carbon fiber reinforced tapes are deposited on a thermoplastic foam core for the additive application of sandwich cover layers. In order to form a cohesive bond between the applied cover layer and the foam core, the two joining partners must be in a molten state. The heating process and the resulting temperature distributions are significantly influenced by the laser power absorbed within the TAFP heating zone. In order to gain a basic understanding of the optical interactions, optical investigations are carried out on carbon fiber-reinforced low-melt polyaryletherketone (CF/LMPAEK) tapes by TORAY and a thermoplastic polyetherimide (PEI) closed-cell foam R82.110 by AIREX with regard to reflection, absorption and transmission. The results are then implemented in an optical ray tracing model to predict absorbed power when depositing tapes onto a foam core. Modeled power distributions show that the tapes absorb way more radiation compared to the foam core. However, radiation reflected from the foam shows a very positive influence on the laser radiation absorbed by the fed tapes near the nip point.
