DETROIT — A CONCEPT dubbed ``design for assembly'' gets a lot of attention in automotive circles these days, but because of mounting interest in the environment, industry planners are now having to think about ``design for disassembly.'' Designers want to make sure their sketches and clay models can be easily translated onto the assembly line. But as the so-called ``green revolution'' takes hold, they have to take their thinking one step further. What happens, they are being asked, when their vehicles are eventually junked? Can they be cost-effectively recycled?
In Europe, strict new vehicle recycling laws will go into effect by mid-decade. And, some planners fret, similar laws may follow here in the United States if the auto industry isn't quick enough to act on its own.
Recycling is actually nothing new to Detroit's carmakers. Junk yards across the country strip abandoned vehicles of radios, engines, even fenders, doors, and other parts that may be resold. Dead batteries are torn apart, their lead reused. The remaining carcass is then sent through a shredder.
At Detroit's Ferrous Processing, one of the Midwest's largest scrap processing facilities, it takes just 37 seconds to transform a 3,500-pound car into pieces. Iron and steel scrap, collected by an electromagnet, are melted down for reuse.
But there's a lot left behind. As much as 10 to 15 percent of a typical car's weight is plastic ``fluff,'' which must be dumped into the nearest landfill. Now, 200 to 300 pounds might not seem like much, but multiply that by the 9 million vehicles junked in the US each year, and it is a major contribution to landfill crowding.
And the situation could get worse. In order to increase vehicle fuel economy, automakers are putting their products on a diet, replacing more and more heavy metal components like bumpers and even body panels with lightweight plastics.
``We must recycle polymer wastes, not just metal,'' stresses E.M. Rowbotham, a recycling expert with Ford of Europe.
In Europe, new laws will require that by mid-decade, 80 percent of the plastics in a junked car be recycled. Manufacturers are responding in several ways.
First, they are trying to make it easier to remove plastic parts from the steel carcass of junked cars. And several companies, including BMW and Volkswagen, have set up so-called ``dismantling stations.''
On newer-model Volkswagens, plastic parts are coded to show which can be reused. To make the parts easier to remove, VW is replacing some screws and bolts with quick-release fasteners.
DESIGNING for disassembly means companies must also rethink the types of plastics they will use in the future. They are likely to abandon some ``problem'' materials, such as Reaction Injection Molding (RIM), in favor of thermoplastics and other recyclable compounds.
Take General Motors Corporation's new Saturn cars. The Saturns are just the latest of several GM vehicles to use plastic body panels, but they're the first to be recyclable.
It isn't always feasible to change compounds, however. ``We must always use the best material available for the job,'' cautions Ford's Rowbotham. So the next step is to find ways to recycle even the most unfriendly materials, like RIM.
GM chemists believe they've found a solution in a process called pyrolysis.
Heating plastic scraps to 1,400 degrees in an oven containing no oxygen ``takes them back to their original materials,'' explains Irvin Poston, manager of composites at GM's Advanced Engineering Staff.
These materials include oil, natural gas, and filler material such as fiberglass, which can be reused. The oil and gas help fuel the fires needed for the pyrolysis process.
Few designers and engineers are ready to put recycling at the top of their priority list. But it is a topic gaining more and more attention. If companies do not take action, warns J. Michael Bowman, general manager of the Du Pont company's composites unit, ``recycling is going to be mandated,'' by the government.''
Even if the industry moves to embrace the idea of recycling, the impact will take years to be felt, warns VW's Buchheim. It will be at least 1995 before the cars on the drawing boards today make it out onto the highway, and many more years before they are dragged back to the junkyards. ``If we start today designing for easy recycling, by 2000, only 20 percent [of the vehicles] would come back, and most of the rest wouldn't be ready for recycling until 2008.''