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Less than a decade ago, carbon fiber components in cars were still an exotic material, and even the top automobile manufacturers treaded carefully in working with this composite. An example of this is when General Motors used a carbon fiber hood in their special edition Corvette Z06. At the time, this piece was the largest carbon composite component used in a production vehicle, although at 2,000 units, it would be more appropriate to call the Z06 a limited-production car.
Unlike today where showing off the carbon weave of a part is practically de rigueur, earlier users of carbon fiber components in production cars chose to paint the parts. And even though designers and engineers of an automotive manufacturer have vast resources at their disposal, there were problems in the initial use of carbon composites in production cars. For these early adopters, the biggest problem was getting a paintable surface of sufficient quality that would pass normal quality control standards. Because a carbon hood, for example, needs such things as a latch, hinges and other parts, these parts needed to be bonded to the composite hood. However, when the part was painted, the trail of adhesive underneath the hood, which was used to bond the parts, would show up as trail of imperfection on the surface of the paint.
In other production cars, such a problem was easily fixed by using a thicker panel. By using a thick panel, the adhesive trail used to bond parts to a composite panel would not show. But using a thicker carbon fiber panel on a hood defeats the purpose of using that composite material. Any weight savings that would have resulted in using a lightweight carbon composite would be negated by a thicker sheet. Although a lighter material would not need as much adhesive, the very thinness of the carbon composite would help to propagate the adhesive trail that would mar the surface finish. The development of new cloths and careful orientation of the fibers helped cure this problem.
But another problem that existed then still remains today. Despite steady research, new types of carbon cloth and refined production processes, making composite parts from carbon fiber is still a lengthy and laborious process. Researchers have found it difficult to drastically reduce the production time for making a carbon composite part. The hand layup of the sheets, resin impregnation and curing time all combine to make a production time measured in hours, which is unacceptable for mass-produced vehicles. This is why in this day and age, cars that make extensive use of composites are limited to the exotic domain. Already though, new developments have been very recently announced that bring down production times to the intervals acceptable to manufacturers. Pretty soon, carbon fiber parts will not be limited just to hoods and aero devices but to entire vehicular structures as well.