OSFIT

The aim was to develop a highly automated manufacturing process for CFRP aircraft frames with thermoplastic matrix. The integral construction method saves cost and time in production process.

In the aviation research project OSFIT the manufacturability of thermoplastic complex parts was investigated using the example of an integral frame. 2D tapepreforms made of CF/PEEK, produced in automated fiber placement, were thermoformed into C-frame. 3D-stiffeners were attached to the inside of the frame by means of fusion joining (injection molding and coconsolidation) to increase buckling stiffness. This eliminates time-consuming assembly processes of individual parts, thus saving manufacturing costs. The use of thermoplastics instead of established thermosets offers many recycling possibilities in addition to the advantages in processing. In the course of the project duration of 4 years (2018–2021), IVW investigated the co-consolidation between the stiffeners as tool inserts and the tapepreform during thermoforming from coupon to component level. The parameters to investigate are the degree of consolidation of the tape-preform and the strength of the joining zone. To support the selection of process parameters, the forming process was simulated and in the course of this, spring-in effects were considered. In addition, an end effector to apply CF/PEEK solid shims was developed to compensate gaps during assembly.