The HyFrame project set out to develop new manufacturing technologies for geometrically complex primary structural components made from fibre‑reinforced thermoplastics, using a passenger cabin window frame as a demonstrator. The core technical achievements began with the design and successful integration of a dedicated welding unit that allows precise fusion of the window frame geometry. This unit was coupled with a process‑induced shrinkage reduction strategy, which lowered dimensional deviations during consolidation and ensured that the final part met the stringent tolerances required for aircraft use. Parallel work produced a robust overmoulding tool that enables the addition of short‑fibre‑reinforced PAEK to the hybrid structure, thereby improving impact resistance and surface finish. The tool was fabricated using advanced machining and surface‑finishing techniques, and its performance was validated through mechanical testing of test coupons that demonstrated consistent strength and minimal warping.
A key milestone was the automation of the preforming chain. By standardising the lay‑up of hybrid textile reinforcements and the consolidation of structural inserts, the project achieved reproducible production of preforms with a high degree of repeatability. Thermoforming of the inserts was optimised through the development of a dedicated mould and process equipment, which reduced cycle times and improved part quality. The hybrid textile itself was produced from commingled yarns, allowing a uniform distribution of reinforcement and simplifying the lay‑up process. Together, these advances enabled the fabrication of a full hybrid thermoplastic window frame that exhibited a significant weight reduction compared with the conventional resin‑transfer‑moulded (RTM) counterpart, while also lowering material and production costs. The project’s cost analysis highlighted substantial savings in both raw material consumption and tooling, and the environmental assessment indicated a reduction in CO₂ emissions across the life cycle of the component.
The collaboration structure was tightly integrated. ACE, the lead partner, coordinated the overall project management, organised the project consortium meetings, and ensured the alignment of technical objectives across the partners. FIBRE (Faserinstitut Bremen e.V.) provided expertise in fibre technology and supported the organisation of technical conferences (TelKons). Hightex Verstärkungsstrukturen GmbH supplied advanced reinforcement materials and contributed to the design of the overmoulding tool. Merkutec GmbH & Co. KG supplied process equipment and assisted in the optimisation of the thermoforming cycle. Saertex GmbH & Co. KG contributed to the development of structural inserts and the consolidation process, while Megatherm Elektromaschinenbau GmbH supplied high‑performance moulding machines and contributed to the automation of the preforming chain. The project ran from 1 January 2018 to 31 December 2020, with two cost‑neutral extensions—first to 30 September 2021 and then to 31 March 2022—to accommodate unforeseen delays caused by the COVID‑19 pandemic. Funding was provided by the German Federal Ministry of Education and Research (BMBF) under the BNBest‑BMBF 98 programme. The final report, submitted on 30 September 2022, documents the successful completion of all technical milestones and confirms that the hybrid thermoplastic window frame meets the required performance, cost, and sustainability targets for future aircraft applications.