Robotic Swing Folding of three-dimensional UD-tape-based Reinforcement Structures

Hybrid fiber-reinforced components made of Long-Fiber-reinforced Thermoplastic (LFT) and unidirectional continuous fiber reinforced tapes (UD-tape) offer great opportunity to reduce weight while saving manufacturing cost compared to monolithic UD-tape components. In such a combination, the excellent formability of LFT is used for filling corners, ribs, and other geometrically complex areas of the component while the UD-tape increases strength and stiffness. Preforming continuous fiber materials, like UD-tape, is a costly step in manufacturing fiber-reinforced polymer (FRP) components. The effort for preforming should be minimized to further improve the competitiveness of the hybrid design. Current preforming processes do not fit the requirements of reinforcement structures. Therefore, they require additional handling steps for positioning the material and costly tooling for controlling the forming of the material. At the same time, the existing processes offer high capability for workpiece complexity, which is not needed as the complex areas in hybrid components are formed by LFT.
In this thesis, a process for the flexible preforming of linear reinforcements from UD-tape strips is designed, commissioned, and optimized. An algorithm for adjusting the preform shape to the preforming process restrictions while maintaining the general shape is presented. Using the novel preforming process, cost for component specific preforming tools can be avoided and deviations in subsequent process steps can be compensated for during running manufacturing.