The WINFRAME 4.0 project was part of the CleanSky 2 initiative and dealed with the manufacturing of composite frames made in thermoplastics.
Regarding composite materials, the main current focus of the industry is on thermoset based composites, for many reasons, among it:
• Thermoset composites have been used in the aerospace industry since the 1960s, and the design and processing knowledge to exploit the materials has developed substantially.
• Major investments have been made in material property databases for thermoset composite man-rated aerospace applications.
• In many cases these databases are treated as company proprietary intellectual property, which makes it difficult to justify investment in alternate materials and processes.
• Industries associated with reinforcement that utilizes thermoset-compatible sizing is mature, including weaving and conversion into prepreg.
• Capital equipment and support services, such as tooling and semi-automation methodologies, are well established.
As expected with a maturing technology, major thermoset composite technology innovations and cost reduction opportunities are less frequent, with some notable exceptions.
Aircraft designers are using more lightweight composite structures to reduce fuel consumption, however, the application of composites in aerospace is not being driven by reductions in costs for composite materials or processing. Today, the most considered cost reductions are coming in the form of fuel savings and not part costs.
One projected breakthrough in the composites industry cost equation is expected to involve the large-scale manufacture of continuous fiber thermoplastic composites.
Potentially thermoplastics can offer improved raw materials and processing costs, as well as improved functional performance, but needs to be developed the processes in which autoclave is not needed, in theory, all processes but in practice, today in some cases, such as AFP with in-situ consolidation are still under development and so some autoclave cycle is needed to finish the part.
Press molding, as well called compression molding, as well sometimes named thermoforming is a process, which is among the quick processes for thermoplastic composite processing, being the part cycle time in the range of 10 min.
The aerospace sector is not away from this to make significant improvements in the process knowledge to be able to use the compression molding process to produce thermoplastic composite parts faster, with complex shapes, and at a reasonable cost that makes possible the use of it in commercial programs, even for smaller aircrafts such as regional ones.
Among components that can be transformed from metal fabrication to thermoplastic composite fabrication by compression molding, there are the windows frames of a regional aircraft, which need to be cost-effective.
Into the introduced context, the objective of the WINFRAME 4.0 project was:
The fabrication of regional aircraft thermoplastic composite windows frames using advanced and innovative industrial manufacturing processes Out of Autoclave in composite, such as compression molding, that allow a significant reduction of part weight (with a consequent reduction of operating costs for airlines) with at least the same overall production costs, compared to traditional metallic solutions.
The main approach carried out was to focus on innovative concepts of manufacturing technologies such as the thermoplastics compression molding process and, for this, WINFRAME 4.0 have carried out:
• Process set up and validation at the full-size level
• Parts fabrication for on-ground fuselage demonstrators
• Industrial cost evaluation
The WINFRAME 4.0 achieved a TRL5-6 at the end of the project which represents:
• Manufacturing process for windows frame is under control in terms of process parameters vs quality of part for instance in terms of void content, providing the geometry was not 1005 feasible without wrinkles
• Assembly process is set, windows frames are equipped, and all quality reports are done and frames were finally delivered for integration into demonstrators.
