Higher-volume cars get carbon fiber
Carbon fiber has finally broken out of its European supercar niche.
The 2013 SRT Viper and the redesigned 2014 Chevrolet Corvette have carbon fiber hoods and other parts, and the Corvette’s production is likely to top 20,000 units this year.
That’s a far cry from the early days of carbon fiber, when a hand-built component took hours to produce and was too costly for volume vehicles.
That’s the good news. The bad news is that carbon fiber is still expensive. The raw material for a carbon fiber part costs $10 to $15 a pound, according to one estimate.
That cost must fall to $5 a pound for economical mass production, industry insiders say.
Some suppliers are working hard to bring down the cost because carbon fiber is strong and lightweight. General Motors says the material is 10 times stronger than steel but weighs one-fourth as much.
A look at the production techniques of Plasan Carbon Composites, the supplier of hoods for the Viper and Corvette, illustrates some of the challenges.
Because the Viper’s hood is so large, it is made by hand in a process that takes 90 minutes. In a plant in Bennington, Vt., workers place layer after layer of carbon fiber fabric pre-impregnated with resin on a mold in an autoclave, or special oven, which then is heated.
‘Marines on the beach’
This costly technique, called pre-preg, produces the high-quality surfaces required for exterior body panels.
At a new plant in Walker, Mich., Plasan has shortened production of the Corvette hood to 17 minutes by substituting a pressure press for the autoclave. The pressure press can be heated more quickly than the autoclave.
Plasan CEO Jim Staargaard says his new process can produce more than 30,000 components annually — enough to break out of the supercar niche.
“We’re like the Marines on the beach,” Staargaard boasts. “We’re the first to do it.”
But Staargaard acknowledges that the relatively slow pre-preg technique is ill-suited to produce the complex shapes required for structural components such as floorpans, cross-car beams, door intrusion beams and door pillars.
To make such parts, Staargaard believes the industry will adopt the less expensive resin transfer molding process. With resin transfer molding, the carbon fiber fabric is placed in a heated mold, and resin is injected into the mold under high pressure. This method reduces the production time for a component to three to 10 minutes.
Staargaard says Plasan likely will obtain the technology for resin transfer molding this year, perhaps through a corporate acquisition.
His timing looks good. Several automakers plan to introduce vehicles that use carbon fiber extensively.
BMW is developing a carbon fiber passenger cell — a key portion of the body-in-white — for its i3 electric vehicle that debuts next year. BMW is expected to produce 30,000 units a year.
The Alfa Romeo 4C sports car, which debuts this year, will have a carbon fiber chassis, according to the automaker. Fiat S.p.A. plans to produce 2,500 units in the first year.
Perhaps most significant about the Alfa Romeo 4C and the BMW i3 is their cost. Neither will carry the stratospheric sticker price of a supercar such as the Lamborghini Sesto Elemento, which boasts a carbon fiber body plus a $2.2 million price tag.
Meanwhile, each of the Detroit 3 is working to reduce the cost of carbon fiber.
In December, GM formed a partnership with Teijin Ltd. of Japan to develop carbon fiber composites for mass-market vehicles. To do so, Teijin has opened a technical center in suburban Detroit.
Likewise, Ford Motor Co. formed a joint venture with Dow Chemical Co. last year to develop low-cost carbon fiber suitable for high-volume production by late this decade.
And Chrysler Group says it’s exploring new uses for the material after the introduction of a carbon fiber hood, roof and decklid on the Viper.
Mike Shinedling, the Viper’s engineering launch manager, says the carbon fiber hood — which weighs 65 pounds — saved 40 pounds.
Shinedling declined to disclose the hood’s cost. But he says the cost of carbon fiber has declined sharply since 2003, when the Viper’s carbon fiber materials cost $35 per pound.
The wholesale cost of a replacement hood for the 2014 Viper will be less than the original Viper’s fiberglass hood. “That shows some progress,” Shinedling says.
The cost may decline more if suppliers can speed manufacturing and develop less expensive raw materials.
Yet another tactic is mixing carbon fiber with less costly fiberglass. The strip that holds the Viper’s windshield in place, for instance, blends those two materials. Chrysler holds two patents for the process.
Carbon fiber’s cost will fall further as other automakers adopt it. And that’s starting to happen.
Continental Structural Plastics of suburban Detroit has won a contract to produce a hood and roof for an unnamed automaker for the 2016 model year.
CEO Frank Macher says annual production will exceed 10,000 units and his company will use resin transfer molding to make the parts.
“The results are fairly dramatic, and we’re working on that right now,” Macher says. “But there’s a lot more work to be done.”
He hopes to speed production by using a carbon fiber made from inch-long chopped fibers instead of long threads. This material is only about 70 percent as strong, but it’s much cheaper. That might work well for the inner portion of hoods, Macher says.
With so much innovation under way, it is unclear which technologies will prevail. That’s why automakers are signing nonexclusive contracts with their suppliers, Plasan’s Staargaard says.
“No one is going to own this market,” Staargaard says. “No one is sure who has the right answer. Everybody is hedging their bets. They are keeping their options open.”