Lyon-based fuel leak repair specialist Sunaero has developed a hand-held composite curing device, which significantly shortens repair times without subjecting the material to excessive heat.

The equipment uses infrared light and was originally developed to speed up polymer seal repairs for fuel systems.

Rather than simply increasing the curing temperature, the engineers optimised the infrared wavelength to the material's properties. The challenge, thereby, was to balance surface temperature against the penetration depth of the heat, and it has been possible to cut the curing time for sealant polymers by factor 12 while keeping the surface temperature at around 45°C (113°F).

The company expanded the principle to other applications and materials. Cure times for certain polyurethane paints could be cut by factor 45, while a device was built for transparent materials.

With the aircraft manufacturers employing composites for ever greater parts of the airframe Sunaero has, not surprisingly, set its eyes on carbonfibre.

Heating blankets, conventionally used for composite repairs, work by conducting heat which can lead to the part's surface temperature increasing much higher than the inside of the material. This is particularly critical as primary structural components may have in excess of 100 plies and be 3-4in [8-10cm] thick, said Sunaero chief Laurent Dumortier.

"The surface can get burned while the heat does not penetrate into the material."

The company is building a prototype curing device for carbonfibre-reinforced plastic, which should become available for commercial use in mid-2012.

Source: Flight International