Vacuum-bag-only consolidation of C/PEKK fiber placed preforms with engineered gas evacuation channels

Vacuum-bag-only (VBO) consolidation of automated fiber placed (AFP) thermoplastic composites can be a cost-effective processing route for large and complex thermoplastic composite structures. This paper explores the possibility of two-step AFP and VBO consolidation of advanced thermoplastic composites. Two commercially available carbon fiber reinforced Poly-Ether-Ketone-Ketone (C/PEKK) thermoplastic tapes were evaluated. Different process parameters were needed for the two material systems. Further, for the first time, an attempt was made to create in-plane air evacuation channels by deliberately introducing gaps between the tapes in the preforms during the placement. In the case of one material system, the VBO consolidation of preforms with and without gaps yielded good consolidation quality with less than 1% voids. In the other case, VBO consolidation of preforms with gaps showed a improved consolidation quality with less than 1% voids than the preform without gaps, indicating that the gaps possibly help accelerate the gas evacuation process.