Pre-impregnated carbon fiber tapes (so-called prepregs) are primarily used for automated tape laying in the aerospace industry. A variant of prepregs are pre-impregnated fiber rovings (so-called towpregs). They are subject to a higher dimensional variance due to the manufacturing process, but offer a considerable cost advantage over conventional prepregs. This makes them particularly beneficial for cost-sensitive applications.
Together with Schütze GmbH, the IFW is researching the processing of towpregs into CFRP sandwich rods in a continuous process as part of the BMWK-funded project "TowPregRod". Within the project, the partner Schütze is conducting the process development and research for depositing towpregs in the direction of the rod. This gives the rods good tensile and compressive properties in particular. The unidirectionally reinforced rod is then provided with angular layers using a multi-orbital lay-up unit developed by the IFW. For this purpose, two orbital carriers rotating in opposite directions, each with up to twelve lay-up units, continuously lay up towpregs over the entire surface of the rod. Above all, the angled layers lead to greater torsional rigidity and allow significantly higher internal pressures in the case of media supply. Thanks to the modular design of the system shown in the picture, a wide range of CFRP rods can be covered. Diameters in the range of 15 - 80 mm and angular positions in the range of 30° - 85° can be produced. In addition, the continuous process allows the production of rods with an uninterrupted length of up to 30 m.
Thanks to the manufacturing technology's high degree of flexibility, the adjustable parameters such as fiber orientation, diameter, towpreg, core material and rod length offer a wide range of possibilities for tailoring the CFRP rod to the respective application.
The project at IFW and Schütze is currently in the start-up phase of the individual systems, followed by process development and process research on the individual processes. In mid-2024, the two processes will then be integrated into one overall process chain and investigated in their production environment.
We would like to thank the Federal Ministry of Economics Affairs and Climate Action (BMWK) for the funding provided as part of the sixth civil aviation research program (LuFo VI), as well as the good cooperation with Schütze GmbH.
Contact:
For further information, please contact Marco Bogenschütz, Institute of Production Engineering and Machine Tools at Leibniz Universität Hannover, on +49 4141 77638 25 or by e-mail (bogenschuetz@ifw.uni-hannover.de).
