CAMPES: Cost Effective and Automated Manufacturing Process for Engine frames and SA Panels (2010-2012)
Collaborative R&D project with NLR and Dutch Space (presently Airbus Defence and Space Netherlands)
There are great benefits to using composites in space structures, because of the low weight and high strength and stiffness of the materials. Manufacturing costs, however, are still high, because of the high amount of manual labour and high material costs. This project focused on developing new, more cost effective composites manufacturing processes for space applications, especially for two product types: launcher engine thrust frames and solar array panels. Radically new technologies are needed to keep down the costs of composite aerostructures.
Airborne’s role in this project was to re-engineer and optimise the designs for a launcher engine thrust frame as well as solar panels for manufacturability and to manufacture the demonstrator structures with improved affordability.
Dutch Space and Airborne manufacture composite sandwich solar array panels for several ESA programs such as Sentinel 1 and 2 and Galileo. These panels have a very high structural performance but current production technologies make them expensive. From the perspective of ESA but even more from the commercial programs there is a strong driver to reduce cost.
In order to maintain and further expand the current position on solar array manufacturing in the Netherlands, new technologies to improve the cost-efficiency are required.
The goal of this project was to develop a novel manufacturing process with game-changing cost-effectiveness for composite space structures.
The concept was to use the following process steps:
To to keep automated manufacturing commercially viable for small to medium size series (typical for the aircraft and spacecraft market), a smart automation approach is needed.
By limiting the process to the lay-up of flat laminates only, a low-cost system could be used instead of the current state-of-the-art but very expensive Automated Fibre Placement machines. A typical AFP machines cost in the order of 3-5 M euro, where a dedicated flat lay-down machine can be made for a cost of around 300.000-400.000 euro. Furthermore, a flat laminating machine can use much wider prepregs, which increases the production efficiency. The automated lay-down machine can make laminates with varying thickness or different laminate layups in specific zones.
In hot forming, heat is used to soften the matrix material, which allows the full laminate to be formed. This is an efficient and state-of-the-art process, which is used in aeronautics programmes to manufacture stiffened skin structures of the wing and empennage. It is not used for space structures yet. The advantage is that the full laminate can be formed in one step, and that the quality of the process can be controlled well. It can be used both for thick and for thin laminates, as used in respectively the engine frame and solar array panels.
In the engine frame design concept, stringers and frames are mounted on the skin. Skins are first cured and then bonded to the stringers with a conventional production process. Co-curing will combine these steps. The stringers and frames are placed on the uncured skin laminate, and during the curing of the skin in the autoclave the stringers and frames are bonded to the skin. In this project, a proof-of-concept machine for automated laydown was constructed, the processes for automated laydown, hot forming and co-curing was developed and tested, and two prototypes were made: a 1/6 segment of the engine thrust frame shell, and a solar array sandwich panel. The impact on design of the products will be evaluated, and a cost comparison and evaluation will be made.
The aim of the project was to achieve manufacturing cost-effectiveness using a combination of the following production processes:
Automated lay-up: automation leads to increased lay-up speeds, especially for flat surfaces.
Hot forming: hot forming after lay-up makes it possible to lay-up on a flat surface.
Co-consolidation: stiffeners are co-consolidated, saving an extra cure cycle for a bonding stage.
Initial testing shows that it is possible manufacture CFRP skins for solar panels substrates using an ATP process, achieving similar quality at a lower recurring cost.
During the project these processes were developed. The demonstrator hardware was manufactured and tested to prove that high-end composite spacecraft structures can be realised with more cost-effective, automated production processes. Furthermore, these manufacturing solutions were proposed for Ariane 5ME composite structures.