GM the big winner in plastics

Examining the GM TPO-based nanocomposite step-assist are, left to right, Basell's Thomas Katchmark, GM's Chuck Biebelhausen, and Blackhawk's Mark Bennett.

With its nanocomposite thermoplastic olefin (TPO) step-assist for the 2002 Chevrolet Astro and GMC Safari minivans, General Motors Corp. in November was named winner of the International Society of Plastics Engineers (SPE) Automotive Division's Grand Award for 2001. The company walked away with first place in four of six categories judged as part of SPE's 31st Innovation Awards Program. More than 60 nominations were submitted for the contest.

The nanocomposite TPO step-assist went on to become the overall winner after having been selected as the top entry in the Materials category—one of six. At the SPE judging event, Thomas Katchmark, GM Account Manager for Basell Polyolefins, described the material as a "major breakthrough in olefin technology." Developed jointly by GM and Basell after two years of development and testing, the material features microscopic clay-particle reinforcement for improved performance in the areas of stiffness, low-temperature ductility, and mar resistance. The material also offers high surface gloss, Katchmark added, and a mass savings of about 10% (although, as described in a more detailed account of the material in AEI's October issue, it can provide mass savings of up to 20%).

The Chevrolet Silverado composite pickup box was developed and produced by the Budd Co. and Meridian Automotive Systems for GM.

The part was molded by Blackhawk Automotive Plastics, Inc. and is said to be the first global automotive exterior application of a nanocomposite TPO. Another benefit of the material is that it can be used in existing equipment.

Winners of the other five categories were:

The self-stowing/rolling convenience system on the 2001 Pontiac Aztek was produced by Lear Corp. The process used to build the structural front-end module (FEM) carrier on the 2000 Audi A2 joins steel to steel with a plastic component that fastens metal like a rivet during the injection-molding process. The high-temperature end tanks for the charge-air-cooler on F-250 to F-550 trucks are made of nylon (replacing die-cast aluminum) reducing component weight by nearly 50%. The hybrid thermoplastic composite (HTPC) rear bumper beam on the 2001 Chevrolet Venture, Pontiac Montana, and Oldsmobile Silhouette vans combines two materials with complementary behaviors.

Body Exterior—General Motors. The 2001 Chevrolet Silverado composite pick-up box, developed and produced by the Budd Co. and Meridian Automotive Systems, is a multi-material application, including reinforced reaction-injection-molded (RRIM) composite, structural reaction-injection-molded (SRIM) composite, and sheet-molding compound (SMC). Materials were provided by Dow Automotive, Bayer, Ashland Specialty Chemical Co., SAI, and Owens Corning. The application, which represents the industry's first full-size pickup with an all-plastic truck box and the largest one-piece SRIM part ever made, eliminates the need for a plastic bedliner. The patented part was made possible by innovations in process technologies.

The new truck box outperformed steel in over 4 million km (2.5 million mi) of road testing and offers a total mass savings of 23 kg (50 lb) vs. steel. The truck box is designed with a patented snap-fit fender assembly.

Body Interior—General Motors. Produced by Lear Corp., the self-stowing/rolling convenience system on the 2001 Pontiac Aztek includes a top, sliding tray over fixed, segregated storage units with a pop-up storage feature for groceries or heavy items. It slides out for easy unloading off the tailgate for items up to 180 kg (400 lb). The storage tray can be deployed and manually lifted for easy transport from vehicle to storage in a garage. It is the first-ever automatic live-loading and stowage system in the automotive industry, according to Lear.

The assembly is constructed via a number of plastic processes, including injection and blow molding. Component suppliers include Duroplast and Flambeau, with the majority of the materials supplied by Spartech Polycom.

Chassis/Hardware/Assembly—Audi AG. One of the two finalists for the Grand Prize, the structural front-end module (FEM) carrier on the 2000 Audi A2, joins steel to steel with a plastic component that fastens metal like a rivet during the injection-molding process. The FEM was developed and manufactured by Faurecia while Bayer supplied Durethan BKV 30 material for the plastic/metal hybrid technology.

The part comes complete from the mold, including five threaded inserts with no secondary operations of any kind. This unique approach met Audi's stringent safety requirements in a lightweight, cost-effective structure that allows for more passenger room. The companies say this is the first time plastic has been used both to join steel to steel in a true structural member and in the injection-molding process.

Powertrain—Ford Motor Co. To handle heat and pressure requirements for the part, materials specified for the charge-air-cooler (CAC) end tanks for F-250 to F-550 trucks equipped with diesel engines include DuPont's Zytel HTN 52G45 and Zytel 70G 30, EMS Chemie's Grivory HT2V-45H, and Solvay's Amodel AS-4145HS. Supplied to Ford by Valeo Engine Cooling, the injection-molded end tanks were produced by Carlisle Engineered Products. The high-temperature tanks made of nylon (replacing die-cast aluminum) reduced component weight by nearly 50%, significantly reduced assembly costs, and boosted performance. This high-volume, injection-molded application of an advanced nylon compound is a first of its kind in North America, according to the companies involved.

The part went from concept to commercialization, including rapid prototyping, in 12 months, illustrating the time benefits achieved with plastics.

Process/Enabling Technologies—General Motors. The hybrid thermoplastic composite (HTPC) rear bumper beam on the 2001 Chevrolet Venture, Pontiac Montana, and Oldsmobile Silhouette vans combines two materials with complementary behaviors. This offers application performance benefits, mass and cost savings, better impact performance, and greater structural integrity than the previous composite product used for this application. The new process, developed by Plastic Omnium, combines Twintex continuous glass-fiber fabric (supplied by Vetrotex) for stiffness and impact resistance with Asahi-Thermofil polypropylene. Process equipment includes a Husky injection-molding machine, two Kuka robots, two infrared ovens, one water-jet cutting machine, plus finishing equipment for the beam's mass production.

- Patrick Ponticel