Thin-ply ADFP preforms for liquid composite moulding: An exploratory study

This study investigates the post-layup behaviour of preforms produced by Automated Dry Fibre Placement (ADFP) and evaluates their suitability for Liquid Composite Moulding (LCM). Thin-ply dry tapes with a polymeric binder were used to produce preforms, and the effects of laminate architecture, deposition and tool temperatures, compaction force, and debulking cycles on compaction, permeability, and infusion performance were examined. Compaction behaviour was characterized using quasi-static and cyclic tests, while in-plane and out-of-plane permeability measurements quantified flow performance in non-staggered and staggered crossply, and quasi-isotropic layups. Results show that elevated tool temperature combined with lower compaction force improves fibre volume fraction ( V f ) uniformity, and staggered stacking reduces out-of-plane permeability. Cyclic compaction revealed that most V f gain occurs within the first ten cycles, reflecting transient viscoelastic relaxation of dry fibres. Observed variations in thickness, V f , void content, and infusion quality reflect within-specimen spatial heterogeneity, providing context for future investigations on how variability may merge and propagate through the process chain. These findings offer practical insight into preform processing and guidelines for optimizing ADFP preforms in LCM applications, supporting more consistent and efficient composite manufacturing.