TROY, MICH. — The next generation of air bags is about to inflate the North American market for automotive plastics, with about half of all vehicles produced in 2005 carrying side-impact systems, up from less than 10 percent this year. "You're seeing large increases from a market that wasn't even there five years ago," said Scott D. Upham, president of Providata Automotive, a research and consulting business based in Ann Arbor, Mich.
"It's huge. You're looking at a lot of applications now that are going with side-impact air bags."
At the same time, manufacturers are considering changes in the way they produce air bags, with composites potentially replacing some metal parts.
Plastics make up the majority of the bags, with nylon and thermoplastic serving as the cushion and covering.
About 9 percent of the vehicles produced in North America this year have some kind of side air bag, built into seats and doors. Another 3 percent will carry a "curtain" style unit, designed to drop out of the headliner trim to protect the head and upper body in a rollover crash.
Dearborn, Mich.-based Ford Motor Co. will begin offering the curtain air bags on its sport utility vehicles this summer.
By 2005, side air bags will go into 50 percent of North American vehicles, and 26 percent of the cars and light trucks will have curtain systems, said Upham, whose company has produced two studies projecting growth of the business.
In Europe, where carmakers adopted side-impact technology in door and seat systems before American firms, side air bags will go into about 23 percent of vehicles this year — up from 17 percent last year — and make it into 58 percent by 2005.
The curtain air bags, meanwhile, will climb from an estimated 3 percent of the market in 2000 to 33 percent in 2005.
"We're already seeing the application rate skyrocket in Europe," said Steven R. Fredin, director of restraint systems engineering for Autoliv North America, during the Feb. 7 Plastics in Automotive Safety Conference in Troy.
"It will expand with the U.S. marketplace coming on line."
Asian carmakers will put side air bags in an estimated 19 percent of its vehicles this year and 45 percent by 2005, with curtain bags going into about 2 percent this year and 20 percent in 2005.
Researchers continually have upgraded the bags, Upham said. One early unit had 88 different components. Now it has fewer than 10.
Now manufacturers want to use lighter materials to replace the heavy steel mountings and brackets that hold the nylon bags in place and the steel-cased inflators.
Delphi Automotive Systems is working with its customers to bring in composites, said Robert L. Jones, staff development engineer for the Troy-based supplier. Other companies are considering magnesium.
"With the improvements in plastics, we're going to be able to increase the replacement of metal pieces," Jones said.
Delphi's studies also would take advantage of plastic molding technology to build fastening systems into the piece, rather than metal's reliance on nuts, bolts and screws.
The key is finding the right kind of material to withstand both the temperatures and pressures when air bags release, he said.
Air bags move at 120 mph when triggered, a force hard enough to break out of their plastic cover, then come to a sudden halt once fully deployed, Jones noted. The heated gas that fills them, meanwhile, reaches up to 600° F.
Delphi also is shopping a new knee air-bag system to its customers. The bolster is a rectangular piece made of thermoplastic olefins and elastomers that sits under the dashboard. In its flat form it is about 11/2 inches wide, Jones said, but expands up to 4 inches during a crash, helping hold a passenger in place during a collision.
The increasing interest in side-impact systems could mean changes in the way some suppliers now handle modules, Fredin said.
While curtain air bags now deploy from trim, Fredin expects automakers to ask headliner producers to integrate the bags into their systems by the 2003 model year.
"We're expecting that's going to change, sooner rather than later," he said.