Plastic grows in auto manufacturing

On average, Baron points out, companies are willing to spend $2 to save 1lb of weight, passing on the cost to consumers who have demonstrated that they are willing to pick up the extra cost, especially when it accompanies something considered eco-friendly or fuel-saving.

However, he warns: "You cannot just take out a steel part and replace it with a plastic or composite - the whole system will need to be redesigned. Material substitution oversimplifies the complexity of lightweighting the car."

And it will not be just one material that will provide the desired weight loss. "It is a potpourri of materials that gets you to lightweight," says deVries.

Too often observers think in terms of "all-aluminum," "all-magnesium," or "only plastic," but that is not realistic, he notes. "You need to look at a cadre of lightweight technologies, especially if you are mass-producing a vehicle."
It is a misconception that plastics are the only lightweight replacement, deVries says. "There is aluminum, magnesium and other lightweight metals - all of which challenge conventional composites for weight savings."

However, neither the composites nor other lightweight providers are as in tune with the automotive manufacturers when compared with the manufacturers of steel. "The steel industry has been catering to the auto industry for nearly a century," says deVries.

Plastic grows in auto manufacturing

"There is an installed base for current traditional material applications that will take time to replace," agrees Adams.

"Steel and aluminum are currently the incumbent and dominant materials in the vehicle world," explains Baron. "So they are somewhat defensive, and are trying to keep the other material suppliers from nipping at their market share."

Plastic's advantage is that it is molded - instead of stamped, as metal is, points out Baron. The molding process is longer, though - a stamp press cycle time for metal is about six seconds - a plastic mold takes about 45 seconds.

Molded parts tend to be on smaller, niche vehicles that are exactly the types of cars buyers are now trending towards. "This is good for plastics," he adds.

"Molds can be a complex shape - something that is difficult to create with stamped steel, but relatively easy with molten polymer in a mold." Meanwhile, multiple parts can be made at one time with a mold, "so the slower molding speed is made up for," says Baron.

"Our vision is that by 2020, the automotive industry and society will recognize plastics as a preferred material solution that meets - and, in many cases, sets - automotive performance and sustainability requirements," says Christman.

Many of today's plastics would enjoy increased use as automakers strive to reduce weight, postulates the ACC.

Polymers found in vehicles include polypropylene (PP), including homopolymer, copolymer and impact-modified; polyurethane (PU); nylon; thermoset and thermoplastic polyester; PC; polybutylene terephthalate (PBT); and acrylonitrile-butadiene-styrene (ABS).

The ACC sees higher heat resistance becoming more important, since newer advanced powertrains have higher operating temperatures.

Source: ICB