Quality Controlled Continuously Formed NCF-Preforms

Abstract

Environmental and economic requirements call for lightweight aircraft design and for cost efficient manufacturing processes. Lightweight design can be reached by the use of composite materials, which have low specific weight. Carbon fiber reinforced polymers (CFRP) are especially suited for air frame production. Full exploitation of the composite’s potential requires a specialized design. One aspect of such a design is a fiber orientation that accounts for the dimensioning load case. Regarding cost efficient manufacturing processes, resin transfer moulding (RTM) using low-cost non-crimp fabrics (NCF) is a very promising option. The preforming process is crucial for optimal and reproducible mechanical properties. Using a fuselage frame as an example, a novel approach of roll forming NCF into a complex curved profile is presented. The patented continuously working principle allows for accurate fiber orientation along the preform and offers a fast and flexible alternative to processes based on solid preform-tools. Automation not only provides cost-efficient processes but also leads to reproducible accuracies. Accompanied by an online quality assurance system that consistently measures the fiber orientation of each layer, the process meets high quality requirements. Inspecting all layers of a stacking enables a complete quality check in the preforming process.