The seal of approval

The global aerospace industry is currently experiencing unprecedented growth and is well on target to hit another record year for 2018. Continued levels of investment mean this trend looks set to accelerate into the near future.

An influx of orders over the past several years has resulted in a record backlog for commercial aircraft with outstanding orders representing approximately nine and a half years’ worth of current annual production. This insatiable appetite for new aircraft is being driven by unprecedented traveller growth in Asian and Middle Eastern emerging markets. As well as the long-term replacement cycle of established carriers.

Fundamentally strong long-term demand in the global aerospace sector is producing increasing demands and challenges for the businesses that supply key components.

As the volume of aircraft production ramps up worldwide the demand for cost and fuel efficiency becomes increasingly more important. Growing numbers of aircraft in the sky make reducing the environmental impact of the industry more urgent than ever before.

Some of these efficiencies have been realised through the development and adoption of composite materials, which are now widely used across aircraft and in many critical components.

To keep pace with the technological advances happening in composite materials, continuous innovation and development of the synthetic elastomers used in aircraft construction is essential.

Conventional rubbers are no longer the optimal choice for the aerospace industry’s requirements and are outperformed by specialist grades of silicone. These advanced materials can maintain their mechanical properties in high temperatures, withstanding the heat of engine environments and when exposed to the extreme cold of high altitude. They remain flexible and non-brittle at temperatures as low as -60°C.

Due to the versatility of silicone rubber, its use is widespread on aircraft; from window and door seals to vibration dampening, cockpit instrumentation seals and LED lighting applications.

The specialised compounds used on aircraft contain additives which further enhance silicone rubber’s natural flame-retardant characteristics, making the material self-extinguishing and reducing the amount of smoke emitted in the event of a fire.

The ongoing technical challenge remains to find ways to innovate material formulations and compounding processes to develop new silicone grades that are both lighter in weight and maintain all their performance and safety characteristics.

Current aerospace silicone grades developed and tested by Viking Extrusions are now 10% lighter than their equivalent flame-retardant grades developed for rail and mass transit usage and 18% lighter than general usage flame-retardant silicones.

The trend of switching internal lighting systems on aircraft to LED provides further opportunities for the use of silicone rubber. Heat resistant properties make silicone the ideal choice for manufacturing lighting seals. However, this provides further technical challenges when meeting the aesthetic requirements of aircraft interiors.

General purpose silicones can be easily pigmented to any colour due to their natural translucent base. This is not the case for aircraft specified silicones, that only accept limited pigmentation due to additives within them.

Ongoing research and testing is looking at new solutions to enable full pigmentation of materials without compromising the safety characteristics of the material.

In a rapidly growing industry that has no margin for error, where the failure of critical components can result in disaster, the continuous challenge for suppliers is to meet the demand for innovation and improved performance without compromising the safety characteristics of materials.

As new material technologies and processes push the aerospace industry forward, Viking Extrusions aim to be leading the innovation in silicone rubber development.

www.vikingextrusions.co.uk