New Process Chain for Realisation of Complex 2D/3D Weft Knitted Fabrics for Thermoplastic Composite Applications

Thermoplastic composites with a complex three-dimensional (3D) shape are attractive construction materials because of their good specific mechanical properties and their possibility to be processed very rapidly. The flat knitting technology bonded with the reinforcing hybrid yarns in horizontal and vertical direction is especially suited for the production of near-net-shape or fully-fashion multilayer weft knitted fabrics (MLG), which could be manufactured with proposed reinforced fibre alignment to obtain improved mechanical properties for high-performance applications. However, in the case of complex and strongly curved components, draping leads to undesired distortions of the stitch and reinforcement structures. In addition, shaping by draping often requires much time and manual effort. In order to effectively produce such knitted fabrics with near-net-shape, it is necessary to create a digital link between shape finding (3D geometry) and its realisation by knitting a 2D contour part and to develop a segmented take-down system for effective production of 3D multilayer weft knitted fabrics performs.