Experimental analysis of gaps and overlaps caused by intra-ply sectorization in the thermoplastic automated fiber placement process

Characteristic gaps and overlaps were analyzed experimentally for sectorized preforms of unidirectional tape with thermoplastic matrix. Laminates with different boundary configurations, layup sequences and staggering patterns were manufactured by the laser-assisted Automated Fiber Placement process. Thermographic analysis is carried out to determine the influence of generated local asperities on the layup process of subsequent plies. Preform homogeneity was analyzed manually and optically using a 3D-scanning device. Specimens were then consolidated using a hydraulic thermal press. Resulting fiber angle distribution in boundary areas was analyzed using an optical measurement technique. Correlation between perform surface homogeneity and in-plane undulation area size is shown.