Prozessstrategien für das automatisierte Preforming von bebinderten textilen Halbzeugen mit einem segmentierten Werkzeugsystem

Stamp preforming offers high potential for the production of complex, shell-shaped preforms, which is a key process in the manufacturing of continuous fibre-reinforced plastics.An innovative approach to improve preform quality consists in a segmented tooling system. The tooling system provides a multitude of options for tool segmentation and sequence, so that an intuitive definition of the tool setting is no longer possible. In addition, sequential closing of the tool segments changes the forming temperature and duration. Suitable activation parameters for the binder must therefore be defined to ensure low resistance to deformation and sufficient stability after the forming process. The objective of this thesis constitutes in the development of a method that defines the process strategy for preforming with a segmented tooling system based on a material and a component geometry. The process strategy includes tool segmentation and sequence
as well as activation time and temperature. In this thesis, different models are developed and validated to define the process strategy, which are then combined into a systematic procedure. A simplified temperature model enables the calculation of the start and end temperature of the forming process for different tool segmentations and sequences depending on the material and contact parameters. ... mehrThe stability of the preform requires a balanced inter- and intra-laminar binder content. To determine this aspect, an impregnation model is presented. That way, a minimum forming and activation temperature as well as a short activation time can be identified. The definition of the tool segmentation is based on a geometric analysis of the part. The tool sequence is optimised by coupling an FE-based forming model with a genetic algorithm that minimises wrinkling in the preform. On the basis of two independent parts, the procedure to increase preform quality is validated. It is thus possible to produce more complex parts by defining a process strategy for preforming with a segmented tooling system compared to a non-segmented forming tool.