Prediction of Gaps in Automated Tape Laying and Their Influence on Porosity in Consolidated Laminates

An efficient way to reduce direct operating costs in aerospace applications is to lower the overall weight. In this context, thermoplastic composites offer a high potential for weight reduction. However, their application requires time and cost-optimized process technologies. Thermoplastic tape laying with subsequent out-of-autoclave consolidation represents such a process technology. Typical process chains consist of several automated steps that can influence the component's quality. Hence, a cross-process approach is applied to identify relevant process parameters. This paper focuses on minimizing the gaps between parallel-placed tapes and thereby reducing their influence on the laminate's porosity. A geometrical model is developed and validated to predict the maximum gap sizes for a tape-laying process as a function of process accuracy, material accuracy, and process parameters. Based on this, a methodological approach is presented to minimize the influence of gaps on porosity. It is validated using automated tape laying and a novel low-pressure consolidation process. The findings make an important contribution to understanding the development of porosity along the process chain for the manufacture of thermoplastic composites for aerospace applications. It can be shown that the approach enables the prediction of gap sizes and allows to minimize their influence on porosity.