R-34
07-30-2003, 06:21 PM
MUNICH – BMW AG continues with research that could lead to a future vehicle with a body composed entirely of carbon fiber.
In a technology presentation to journalists here, BMW says the weight-savings of a carbon-fiber body and its associated fuel savings would offer significant lifecycle benefits.
“BMW Group experts have determined that CFP (carbon-fiber reinforced-plastic) bodyshells or body structures, by reducing fuel consumption to an above-average extent during the use of a vehicle, are able to offer significant benefits in terms of their ecological balance," says a company document.
Most carbon-fiber components or body panels in the past have been built up by hand, covered with resin and “baked” in an oven-like autoclave. That method, however, suits only low-volume production.
Over the past two years, BMW has developed an automated process to make carbon-fiber parts, which it now is using for the roof of the BMW M3 CSL in a pilot project.
The part, made at BMW's Landshut plant, weighs 13.2 lbs. (6 kg) less than a steel roof and leaves the mold with a Class-A finish. The material is covered only with a clearcoat, which displays the tissue structure of the material.
Although the M3 CSL is a low-volume project – just 1,500-1,800 units between June and the end of production at year’s end – it is providing experience with the automated process.
"It's not just carbon fiber," says a BMW spokesman in the U.K. "We are using various light plastics and other materials to reduce weight where they provide equal or better strength."
For example, BMW’s new 6-Series coupe, he says, employs aluminum for the hood, the trunklid is in one kind of plastic composite, and the fenders use a different plastic.
The M3 CSL’s carbon-fiber roof is made in pilot facilities at two Landshut technical centers – one for plastic body skins, and the other for the CFP material. Production is a 3-stage process:
Five layers of carbon fibers are placed on top of one another for pre-forming.
The pre-formed mat is placed in a giant RTM (resin transfer molding) press, where transparent epoxy resin is injected.
Finally, the roof hardens in the heated mold, is removed by a robot and coated by the clearcoat paint.
The automated procedure is five times faster than production by hand, says BMW.
Although volumes are low, the project is giving BMW additional production experience with carbon fiber that could see its use expanded to other structural parts in the future for higher-volume vehicles.
The body of a modern automobile accounts for 15%-20% of its overall weight, and carbon-fiber body parts weigh 30% less than aluminum and usually at least 50% less than steel. An all carbon-fiber body thus could reduce the overall weight of a vehicle by up to 10%, with no concession in terms of stiffness and body strength.
BMW has experience with one wholly carbon-fiber car – the Williams F1 BMW FW25 Formula 1 racer.
© 2003, Primedia Business Magazines and Media, a PRIMEDIA company. All rights reserved. This article is protected by United States copyright and other intellectual property laws and may not be reproduced, rewritten, distributed, redisseminated, transmitted, displayed, published or broadcast, directly or indirectly, in any medium without the prior written permission of PRIMEDIA Business Corp.
wardauto.com
In a technology presentation to journalists here, BMW says the weight-savings of a carbon-fiber body and its associated fuel savings would offer significant lifecycle benefits.
“BMW Group experts have determined that CFP (carbon-fiber reinforced-plastic) bodyshells or body structures, by reducing fuel consumption to an above-average extent during the use of a vehicle, are able to offer significant benefits in terms of their ecological balance," says a company document.
Most carbon-fiber components or body panels in the past have been built up by hand, covered with resin and “baked” in an oven-like autoclave. That method, however, suits only low-volume production.
Over the past two years, BMW has developed an automated process to make carbon-fiber parts, which it now is using for the roof of the BMW M3 CSL in a pilot project.
The part, made at BMW's Landshut plant, weighs 13.2 lbs. (6 kg) less than a steel roof and leaves the mold with a Class-A finish. The material is covered only with a clearcoat, which displays the tissue structure of the material.
Although the M3 CSL is a low-volume project – just 1,500-1,800 units between June and the end of production at year’s end – it is providing experience with the automated process.
"It's not just carbon fiber," says a BMW spokesman in the U.K. "We are using various light plastics and other materials to reduce weight where they provide equal or better strength."
For example, BMW’s new 6-Series coupe, he says, employs aluminum for the hood, the trunklid is in one kind of plastic composite, and the fenders use a different plastic.
The M3 CSL’s carbon-fiber roof is made in pilot facilities at two Landshut technical centers – one for plastic body skins, and the other for the CFP material. Production is a 3-stage process:
Five layers of carbon fibers are placed on top of one another for pre-forming.
The pre-formed mat is placed in a giant RTM (resin transfer molding) press, where transparent epoxy resin is injected.
Finally, the roof hardens in the heated mold, is removed by a robot and coated by the clearcoat paint.
The automated procedure is five times faster than production by hand, says BMW.
Although volumes are low, the project is giving BMW additional production experience with carbon fiber that could see its use expanded to other structural parts in the future for higher-volume vehicles.
The body of a modern automobile accounts for 15%-20% of its overall weight, and carbon-fiber body parts weigh 30% less than aluminum and usually at least 50% less than steel. An all carbon-fiber body thus could reduce the overall weight of a vehicle by up to 10%, with no concession in terms of stiffness and body strength.
BMW has experience with one wholly carbon-fiber car – the Williams F1 BMW FW25 Formula 1 racer.
© 2003, Primedia Business Magazines and Media, a PRIMEDIA company. All rights reserved. This article is protected by United States copyright and other intellectual property laws and may not be reproduced, rewritten, distributed, redisseminated, transmitted, displayed, published or broadcast, directly or indirectly, in any medium without the prior written permission of PRIMEDIA Business Corp.
wardauto.com