Processing of Thermoplastic Composites Using a Powder Slurry Technique. II. Coating and Consolidation

Powder impregnation techniques have been developed to increase design and manufacturing flexibility with thermoplastic composites. This paper presents an experimentally based analytical investigation of the coating and consolidation processes of powder impregnated tows. Polymer flow during towpreg manufacture was studied and the various stages of fiber coating were identified. A coalescence model was developed to predict the degree of coalescence of the powder as a function of the processing parameters. The stiffness of the final towpreg was found to be related to the extent of coating of the fibers with the powder. A consolidation apparatus was fabricated to determine the effect of key processing variables upon the degree of consolidation of the towpreg. The plaques produced from the consolidation experiments were evaluated using 3-point flexure tests and image analysis. The influence of each parameter and parameter interaction was determined.