Passenger aircraft doors are still primarily manufactured by hand. A particularly time-consuming aspect is assembling the door structures using screws and rivets, with numerous intermediate steps required to prevent direct contact between different materials, which would otherwise lead to corrosion.
However, replacing aluminum, titanium, and thermosets with primarily thermoplastic carbon fiber composites (CFRP), which can be welded together automatically without separating layers, makes the process much faster. Manufacturing time for the door structure drops from 110 hours to just 4. A research project by Fraunhofer IWU, Fraunhofer LBF, Trelleborg, and Airbus Helicopters has shown this clearly.
Another key factor in shortening assembly times is the modular design for different aircraft door variants. The project team specifically looked for components across various door models that could be standardized, finding success with the crossbeam, and designed a fully automated assembly line for the most common models with fixtures and clamping elements suitable for resistance and ultrasonic welding technologies.
Dr. Rayk Fritzsche, project lead at Fraunhofer IWU, stated: "Together with our colleagues at Airbus, we closely analyzed all door structures to adapt the geometries for automatic clamping and joining. As a result, we could reorganize and fully automate the individual assembly steps. This way, we slash the lead time to a fraction of what it used to be." Manual labor is now only required to install the locking mechanism.
Two almost identical assembly and joining lines ensure redundancy if one line is unavailable. Thanks to standardization measures, batches of 10 doors can now be organized, allowing fully automated line retooling at the end of each shift to accommodate the following model series, with a production capacity of 4,000 doors per year.
Maxi Grobis, from IWU's factory planning, simulation, and evaluation team, simulated all technical and economic aspects of the new assembly line. "To deliver a truly integrated solution, we analyzed the entire door production and assembly process and translated it into a dynamic cost model," Grobis emphasized, noting her integrated simulation approach also reduced planning time by about 25%.
Source: www.iwu.fraunhofer.de
