Abstract
The relationship between impregnation process, consolidation quality and resulting mechanical properties of GF/PP and CF/PEEK thermoplastic composites manufactured from powder/sheath-fibre bundles have been investigated. A small processing mould was used to simulate the different processing conditions (i.e. applied pressure, holding time and processing temperature). The consolidation quality of finished samples were characterized mainly by microscopic studies of material structure, density measurements and characterisation of mechanical properties through a small transverse flexure testing facility. A model for qualitatively describing the consolidation process of powder/sheath-fibre bundles was developed, which predicts variations of void content during consolidation as well as the time and pressure required to reach full consolidation. Good correlations between predictions and the experimental data indicate the success of the approach. Based on a desired, minimum level of void content (e.g. XV=5% for GF/PP and XV=2% for CF/PEEK composites), optimum processing windows for manufacturing of composite parts from powder/sheath-fibre preforms are suggested.