Simultaneous needle drive - technology and knitting sequence development for form-fitting products on flat knitting machines

• Applicant: Professor Dr.-Ing. Chokri Cherif
• Subject Area: Lightweight Construction, Textile Technology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 548197397

A significant reduction of CO2 emissions while at the same time reducing use of energy and resources requires a holistic view on the life cycle of products, taking into account application and manufacturing scenarios and options as early as the design phase. The application of lightweight construction principles during design and implementation of components and, in particular, fiber-reinforced plastic composites (FRP) is promising approach. The proposed project intends to provide new concepts for flexible production of FRP in medium and large series applications based on methods and strategies for waste-free and load-adapted design and manufacturing of preforms. This requires a flexible, low-resource and low-energy production methodology that is also the basis for comprehensive process automation. The scientific approach to increasing flexibility and productivity is to replace classic, carriage-based, sequential needle ejection in knitting with a new system for the functionally appropriate, simultaneous ejection of each individual needle (FlexKnit). The implementation of this approach allows completely new knitting sequences, such as synchronous stitch formation and transfers in many areas across the knitted width. Each doubling of the simultaneously active knitting areas doubles the productivity of the flat knitting machines. Another objective is to provide a numerical knitting process model for the simulative description and mapping of dynamic changes in yarn movement and demand that occur as a result of the knitting process, as well as the resulting local yarn tensions. This creates the prerequisites for high reproducibility of functional properties, such as drapability, electrical conductivity or the arrangement of weft yarns according to load or geometry requirements. In addition, product-related manufacturing parameters or measures to increase the knitting speed can be virtually derived and evaluated in advance in line with requirements. For this purpose, the processes of stitch formation during the joining of the individual knitting areas are to be simulated depending on the specific knitting method used, and correlations and interactions with regard to the product properties are to be derived for parallel knitted fabric production in each area. This makes it possible to manufacture textile semi-finished products with properties that can be adjusted according to requirements, e.g. local drapability for the production of complex-shaped FRP components in a highly productive and waste-free manner. The FlexKnit approach helps to make the advantages of form-fitting knitted products more economically attractive in terms of sustainability, reduced energy consumption and resource conservation and to significantly increase their market share. The direct manufacture of the products increases the degree of prefabrication and avoids completely cost-intensive manual assembly and reworking.

• DFG Programme: Research Grants