Industry News

Composite materials are essential in the aerospace industry. To shape them, autoclaves, high-pressure and high-temperature chambers are traditionally used. But to optimise energy consumption and production time and costs, Fer’Incub, the R&D division at Ferry Capitain Foundry, has developed a self-heating mould technology that eliminates the need for an autoclave. In the aerospace industry, technological innovation is a crucial driver of competitiveness and performance. Particularly, composite materials play a dominant role due to their lightness and exceptional strength, essential traits for optimising fuel consumption and the load capacity of aircraft. Traditionally, the shaping of these composites involves the use of autoclaves, high-pressure and high-temperature chambers that cook the composite materials to optimise their mechanical properties.

However, this method is far from being without faults. Autoclaves are notoriously energy-intensive, involve high operational costs and long production cycles, which can hinder the speed and flexibility of production. In this context, the need to develop more efficient alternatives has become a strategic issue for manufacturers and researchers in the field of composite materials.

It is with this perspective that Ferry Capitain Foundry and its R&D division – named Fer’Incub – have developed a revolutionary self-heating mould technology. This innovation eliminates the need for an autoclave by integrating heating channels directly within the foundry pieces made of Invar, an alloy known for its very low thermal expansion.

These channels facilitate the circulation of a heat transfer fluid, essential for heating, maintaining temperature and cooling the tooling, thus allowing precise control of thermal conditions throughout the manufacturing process. Moreover, the channels are strategically positioned at a constant and optimised distance from the moulding surface, a feat that is impossible with traditional drilling techniques, offering unmatched heating homogeneity and improved mechanical properties of the finished composites.

FRAMES Project

As part of the European Clean Sky initiative named Frames, Ferry Capitain & Fer’Incub have distinguished themselves not only as subcontractors, but also as key technological partners. The FRAMES project, focused on the maturation of innovative technologies for the aerospace industry, specifically explored the potential of self-heating moulds for large-scale applications. Ferry Capitain and Fer’Incub made significant contributions to this project by providing their expertise in foundry work and metallurgy, essential for adapting these moulds to the complex requirements of large-size composites.

To concretely illustrate the advantages and viability of the self-heating mould, Ferry Capitain and Fer’Incub participated in the design and creation of an impressive prototype casting.

Tooling description

The foundry mould, specifically developed for this prototype, incorporates several technical innovations. First, the mould has dimensions (2,665 x 1,760 mm, height 460 mm) suitable for large aeronautical components, including 38 strategically placed inserts to optimise the heating process. Moreover, the creation of the mould involves advanced foundry and casting techniques, showcasing the capabilities of Ferry Capitain and Fer’Incub to handle complex and large-scale structures. A crucial step in the development and fine-tuning of this prototype was the simulation of the casting, used to predict and optimise the distribution of molten metal and to ensure the quality of the final mould.

Materials innovations: the Invar Grades of Ferry Capitain and Fer’Incub

Recognising the specific needs of thermosetting (TD) and thermoplastic (TP) composites, Ferry Capitain has developed two distinct Invar alloys:

• Ferrynox N36: ideal for applications requiring resistance up to 250°C (480°F), this material is primarily used for TD composites.
• Ferrynox N29K: designed to withstand temperatures up to 400°C (750°F), this material is preferred for TP composites.

Both alloys, Ferrynox N36 and Ferrynox N29K ensure dimensional stability with expansion coefficients that remain constant up to the maximum indicated temperatures (Figure 6).

Moreover, these alloys can be combined within the same tooling, thus exploiting their differential expansion to offer innovative local compression solutions. This feature is particularly beneficial in co-consolidation operations, where precise compression is crucial for the quality and integrity of the final composite.

Outlook

The creation of this innovative tooling by Ferry Capitain and Fer’Incub clearly demonstrates the feasibility of creating large-scale self-heating mould systems for out-of-autoclave applications. This development has not only proven that it is possible to achieve high heating and cooling rates, but also to maintain good thermal homogeneity across the tooling. The results obtained suggest that even larger dimensions could be considered, paving the way for broadly expanded industrial applications and potentially transformative impacts on the composites sector.

To fully capitalise on the potential of this technology, extensive work in terms of testing, development and industrial research is essential. It is crucial to qualify and ensure the reproducibility of thermal exchange at every point of the mould. This includes a detailed analysis of the position of the inserts, their dimensions and length, the volume and temperature of the heat transfer fluid, as well as the heat exchange coefficient and thermal footprint.

Additionally, it will be important to study the pressurisation of the upper and lower moulds, a process previously managed by the isostatic conditions of autoclaves, to further optimise the consolidation process. These steps are indispensable to ensure the efficiency and reliability of the tooling under varied operational conditions and for different composite applications.