Production of carbon composites for aircraft production creates a large amount of scrap—expensive scrap because of the high content of carbon fiber. A Boeing engineer says that more than two-thirds of the carbon fiber it buys (up to $30 per pound) ends up as scrap.
Boeing has launched at least two partnerships to develop
technology and markets for carbon fiber scrap, in addition to its own internal efforts. The other major issue will be the ability to re-use composite from aircraft such as the 787 Dreamliner after they are decommissioned.
The first commercial application for Dreamliner scrap to go public was announced this week by RTP (Winona, MN).
Werner Paddles (Sultan, WA) is using recycled carbon scrap as a way to improve aesthetics of its jet-black kayak paddle blades. Earlier versions required higher loadings of reinforcement, creating some blemishes on the surface.
“The carbon fiber compound Werner used for the blades is more commonly found in the manufacture of structural components where surface quality is not a priority,” says Tim Bailey, engineering manager of Werner’s molder, KASO Plastics (Vancouver, WA). “For Werner, the cosmetics of the material were as important as the strength, rigidity, and other physical properties.”
The RTP compound is also easier to process because of the reduced reinforcement loading. Costs for the two compounds are described as comparable. Neither the thermoplastic resin nor the loading of the fiber was disclosed for competitive resins.
“The recycled/reclaimed CF loading percentage is lower than virgin CF formulations that were trialed,” Kirk Fratzke of RTP told The Molding Blog. “The CF used for aircraft production is a higher grade than what is typically used in reinforce thermoplastics and thus a lower loading produced properties similar to higher loaded virgin CF compounds.” The lower loading allowed for better surface appearance in the paddles.
More favorable news on the quality of the recycled Dreamliner material comes from Boeing.
“Our research has shown that recycled carbon fiber
composite material is comparable in strength and quality to new fiber,” says Bill Carberry, leader of the airplane and composite recycling program at Boeing.
Not surprisingly, a major goal at Boeing is to find aircraft applications for carbon composite scrap. Applications under investigation include nonstructural aircraft components from arm rests to smaller parts, such as electronics casings, brackets and hose clamps. Last year Carberry’s group built a proof-of-concept galley door with production scrap collected at Boeing’s new Dreamliner factory in Charleston, SC.
“Recycled carbon fiber components still need to meet the aircraft’s design requirements and mission; they can’t increase the cost or weight of the part,” Carberry says. “It’s a challenge, but the benefits are worth it if we can reuse our composite scrap and put it back into new manufacturing.”
Production rates are ramping up now in Charleston, SC and Everett, WA for the long-delayed Dreamliner, which is 50% CFRP. Composite materials make up 43% of the airframe of the Bell Boeing V-22 Osprey, which is being manufactured in Philadelphia.
Boeing is also now investing $1 million annually (for at least three years) in a strategic research collaboration with the University of Nottingham’s Faculty of Engineering in all its composites recycling activities.
Boeing helped establish the Aircraft Fleet Recycling Association to promote carbon- fiber reinforced plastic (CFRP) scrap. The group estimates that recycling carbon fiber uses 95% less electricity and is 30% less expensive than making new composite material. The group now has close to 70 members. Airbus is exploring recycling in a separate initiative, the Process for Advanced Management of End-of-Life Aircraft (PAMELA) consortium