21 June 2013 10:01 [Source: ICB]
The high cost of the material and lengthy production-line cycle-time mean that vehicle makers are cautious
Market sources who supply raw materials such as polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) to vehicle parts makers are not concerned about carbon fibre moving into mass-market vehicles - at least not yet, sources said on 12 June.
"It's something that's been talked about for the past decade," said one source. "It is coming? Certainly. But not anytime soon."
US vehicle manufacturers have been slow to use carbon fibre, mainly because of time and cost reasons
Copyright: Rex Features
ACN MAKERS EXCITED
The only petrochemical producers who are at all excited about carbon fibre are acrylonitrile (ACN) makers. That is because, depending on who you talk to, it takes 3-5 lbs of ACN to make 1 lb of carbon fibre.
Vehicle manufacturers are looking at carbon fibre because it is roughly 10 times as strong as steel and a quarter of the weight. It is a material that could help them meet increasingly stringent fleet fuel-economy standards that are slated to rise to 50mpg by 2025. They are looking at an aerospace-grade of carbon fibre called polyacrylonitrile (PAN). But PAN costs roughly $15/lb, or about $33,000/tonne (€24,750/tonne), compared with about 40 cents/lb, or $882/tonne, for steel.
Carbon fibre is also more expensive than some of the petrochemicals that go into making vehicle parts. The spot price for ACN is about $1,650/tonne, while ABS is priced at about $3,000/tonne and PC costs about $3,700/tonne, depending on the grade.
Carbon fibre has other obstacles it must overcome before it can be adapted to mass-market auto making. For instance, most carbon-fibre components are made in big ovens called autoclaves that bake parts at intensely high temperatures and pressures. But the autoclave cycle-time needed to make something such as a car bonnet is 90 minutes. That may be good enough to make body panels, cross braces and other parts for a car like the low-volume Dodge SRT Viper, but it is not nearly fast enough for high-volume auto factories that are rolling a car off the line every 60 seconds.
At a new plant in Walker, Michigan, outside of Detroit, auto supplier Plasan has shortened the production time for the Chevrolet Corvette's carbon-fibre bonnet to 17 minutes by replacing the autoclave with a pressure press that can be heated more quickly. Plasan CEO Jim Staargaard said his new process can produce more than 30,000 components annually, which he estimates can meet production demands beyond low-volume, niche products such as the Viper and Corvette.
"We're like the Marines," Staargaard said. "We're the first to do it."
Staargaard acknowledges that the technique is still not suited to make complex shapes required for structural components such as floor pans, cross beams, door beams and pillars. Plasan is working on a less-expensive resin transfer moulding process in which carbon-fibre fabric is placed in a heated mould and resin is injected into the mould under high pressure. The process reduces production time for a component to three to 10 minutes, he said.
Despite the high cost of carbon fibre, some vehicle manufacturers are integrating the high-strength, low-weight material into some products. BMW is developing a carbon fibre passenger cell 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 fibre chassis, according to the auto maker. Parent company Fiat SpA, which also owns Chrysler, plans to produce 2,500 of the Alfa units in the first year.
The more important point, sources said, is that neither the Alfa Romeo 4C nor the BMW i3 carry the stratospheric sticker price of a supercar such as the Lamborghini Sesto Elemento, which comes with a carbon fibre body and a $2.2m price tag.
In the US, GM formed a partnership with Teijin Limited of Japan to develop carbon fibre composites for mass-market vehicles. Teijin has opened a technical centre in suburban Detroit.
Similarly, Ford formed a joint venture with Dow Chemical last year to develop low-cost carbon fibre suitable for high-volume production by late this decade. Chrysler says it is exploring new uses for carbon fibre after using it for the bonnet, roof and deck lid on the Viper. Chrysler said just making the bonnet alone out of carbon fibre saved 40lbs.
With so much carbon-fibre innovation under way, market sources said it is unclear which carbon-fibre technologies will prevail. That is why auto makers are signing nonexclusive contracts with their suppliers.
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