TROY, MICH. — Automaker DaimlerChrysler AG is continuing its proposal to make thermoplastic car body panels, but it is widening its focus beyond injection molding to thermoforming and also is considering composites.
The carmaker still calls injection molding its "current leading candidate" to produce a thermoplastic-bodied car for the market sometime later in this decade. But its search for a top-quality finish also has prompted it to look at other processing options, said Thomas S. Moore, vice president for the company's Liberty & Technical Affairs research and engineering unit.
"We are looking more and more at thermoplastic injection molding but also thermoforming and even lightweight [sheet molding compound]," Moore said Feb. 5 during the Society of Plastics Engineers' Global Automotive Safety Conference in Troy.
"Just because we're focusing on a current leading candidate's approach, that doesn't mean you ignore all the rest. If we could use some new blend of peanut butter and bananas that would perform, we'd use that."
The automaker, which has offices in Stuttgart, Germany, and Auburn Hills, Mich., has created model cars with injection molded bodies on an aluminum frame as part of its involvement in the Partnership for a New Generation of Vehicles.
The PNGV encourages automakers to create an affordable family sedan that will get up to 80 miles to a gallon of fuel. DaimlerChrysler introduced its plastic-bodied ESX3 experimental model last year — a car that would get 72 miles per gallon with a diesel engine and cost about $7,000 more than the price of an equivalent car.
DaimlerChrysler made parts for the concept car on the 8,800-ton press at Husky Injection Molding Systems Ltd.'s Detroit Technical Center in Novi, Mich.
Now DaimlerChrysler must refine that concept if it wants to meet the goal of producing an actual vehicle by the 2007 model year, Moore said.
That means tweaking the diesel program to fit U.S. standards, reducing the cost difference and finding a way to get a good exterior look to the vehicle.
The car company must apply a glossy finish in the molding process, he said. Traditional techniques would push the cost back up.
"So how do we get this plastic looking like a beautiful paint job, without the paint shop?" Moore said.
The company is looking at in-mold painting, paint films and thermoforming with a film. Thermoforming, however, will not allow the car company to get the same complex shapes allowed through injection molding.
Although SMC would solve some of the finish problems, Moore added, "We're trying to make thermoplastics our first priority.
"We're looking for whatever material is ideal for our needs."