DEARBORN, MICH. - Automakers and their suppliers often talk about lighter cars and cutting costs. But suppliers asking the natural question, ``How much is weight-saving worth?'' will get a jolting answer from Thomas S. Moore, Chrysler Corp.'s head of advanced vehicle engineering. ``The truth, in my opinion, is zero,'' he said during the Advanced Composites Conference and Exposition, held Nov. 6-9 in Dearborn. The Engineering Society of Detroit and the Society of Automotive Engineers, based in Warrendale, Pa., sponsored the conference.
Moore said the extra cost is worth it if the use of a composite, instead of a steel component, moves a car to the next lower inertia class for a fuel economy boost.
``If it doesn't get the vehicle to the next inertia class, the weight saving is worth nothing. That is why applications come into production and then disappear when the next all-new model comes out and meets the targeted inertia class without the composite hood, lift gate or the like. For this reason, I think new applications have been one step forward, two steps back for many uses in the past decade,'' Moore said.
He said putting the steel vs. plastic struggle in perspective calls for talking of the entire car body, the body-in-white, or steel shell of the car. In that case, the cost penalty for using a composite, instead of steel, must be zero.
He suggested that the plastics industry form an alliance like the steel industry has had for about five years, during which great technological strides have been made. Such an alliance would be ``a strong, cooperative team to solve the cost issues,'' he said.
``Steel has been getting lighter and less expensive in recent years, and one steel industry study shows a trend towards a 35 percent further weight reduction and 14 percent cost reduction. With the average car price nearing $20,000 and leasing outgrowing purchasing, consumer purchasing power can't continue to accept added cost,'' he said.
``We simply cannot contain cost increases or pass them along to customers anymore, no matter how beneficial these changes, like improved fuel economy, more safety, more electronic gadgets and so forth,'' Moore said.
The best hope for an all-composite car is the Supercar program with its goal of an affordable 80-miles-per-gallon midsized vehicle, he said. That car will require an expensive hybrid electric powertrain so there will be absolutely no room for added cost in its body.
Moore agreed that tooling costs with plastic are lower than for steel and parts integration, but he called the true cost of steel amazing. He said galvanized steel costs about 40 cents a pound.
``The least-cost composite I can find is [sheet molding compound] at 80 cents a pound. Because cycle times are at least five to 10 times faster for steel, and SMC has more labor, there is no way to achieve a comparable total cost at this material-cost level. Using [structural reaction injection molding] at $1.20 a pound or [resin transfer molding] at $1.50 is even less encouraging,'' Moore said.
``How can an 80-cents-a-pound material compete with 40-cent material if the weight saving is only 25 percent? To be competitive, a composite material cost of 50 cents a pound should be the objective,'' he said.
Moore said the plastics industry should drop its focus on low-volume cars and concentrate on the materials-cost issue.
He said the basic oxygen furnace and continuous casting came into the steel business in the 1960s and 1970s and have been the key to cost containment. He said the plastics business needs its own breakthrough basic oxygen furnace.
``Resin suppliers should focus on research to make dramatic reductions in cost. In addition, efforts must be undertaken to automate mold loading and unloading, combine mold and press for high-volume dedicated production parts, reduce cycle time and further integrate and combine parts in design,'' Moore said.