While fuel housings for aerospace applications are traditionally designed in metal, Egmond Plastics (Alkmaar, Netherlands) has developed a proprietary technology enabling them to be produced from high-performance engineering plastic materials. This technology, called fusible-core technology, allows for undercuts in injection molding. Combined with the use of carbon-fiber-reinforced grades of Victrex PEEK polymer, the technology has achieved cost savings of over 30% and weight savings of up to 50% in the production of these complex fuel housings for the global aircraft industry, according to Egmond.
In the past, aluminum had generally been specified for the production of fuel-containing parts. However, not only does carbon-fiber-reinforced PEEK offer superior fatigue performance compared with aluminum, it also meets all the engineering requirements for this application, including stiffness, effective flame, smoke and toxicity (FST) performance, and resistance to aggressive chemicals, including to jet fuel and Skydrol hydraulic fluid.
Fuel housings for aerospace applications have very complex inner geometries that cannot be produced using conventional injection molding technology. Egmond Plastic's fusible-core technology enables complex hollow housings, manifolds, and pipes to be molded, however.
"Our technology, in combination with carbon-fiber-reinforced Victrex PEEK polymer, delivers numerous benefits," explained Richard Brandwijk, Managing Director at Egmond Plastic. "These include cost reduction, enhanced manufacturing speed, and weight reduction leading to improved fuel efficiency and reduced CO2 emissions. Along with part consolidation, this exceptional technology and material combination enables the design of very complex parts, beyond the capabilities of standard injection molding and metal processes."
Utilizing a near net-shape manufacturing process for the fusible core allows for an 80% time saving versus machined parts, according to the company. Secondary treatments for corrosion protection, such as anodizing, can be eliminated. Lead times can be reduced by 50%. These factors collectively result in part cost savings of more than 30% versus metal equivalents. Parts can range in size all the way up to 30 cm x 30 cm x 40 cm (11.8 in x 11.8 in x 15.8 in), and typically the process is used for production runs of up to 2,000 parts.
Egmond's fusible-core technology has already established a proven track record using Victrex PEEK in a fuel pump for the Eurofighter Typhoon, a jet fighter in use in several European countries. This pump has been in successful operational use for more than 20 years.