Creative ideas and new materials were well represented at the third annual Automotive Composites Conference, presented jointly by the Automotive and Composites divisions of the Society of Plastics Engineers (SPE). Held Sept. 9-10 at Michigan State University's (MSU) Management Education Center (Troy, Mich., U.S.A.), the conference showcased innovations in product forms and interesting hybrids of composite technology, living up to its theme "Cost-Effective Solutions for Lighter, Safer Vehicles."
Conference chair Renita Jones of BP-Curv Composites (Austell, Ga., U.S.A.) noted that the 300 automotive-related engineers, researchers and executives in attendance represented a 10 percent increase from 2002, demonstrating the growing popularity of the ACC forum. Four keynote sessions, 57 technical papers and 20 exhibits brought attendees up-to-date on the latest developments in the automotive composites arena.
Jones observed a trend among exhibitors and speakers toward increasing use of hybrid solutions for achieving the dual objectives of lower cost and lower weight. This was most evident in long fiber-reinforced thermoplastic (LFRT) components, perhaps the fastest growing sector of the automotive composites market. Quadrant Plastic Composites (Lenzburg, Switzerland) presented a paper on the combination of its recently introduced SymaLITE GMT (glass mat thermoplastic) material with a thin layer of coil-coated aluminum to achieve a stiffened, lightweight body panel with aesthetic characteristics (for the full story, see "News," p. 13). Quadrant also displayed an inner hatchback door panel for the Nissan Murano, produced from a combination of standard GMT, reinforced across the door intrusion area with Twintex woven polypropylene/fiberglass. For the Murano, this inner panel is combined with an unreinforced thermoplastic outer panel.
Dieffenbacher GmbH (Eppingen, Germany) spotlighted Twintex fabric combined with direct-LFT materials for high-volume applications. And BP-Curv Composites introduced its self-reinforcing polypropylene sheet as a reinforcement in traditional injection molded or compression molded parts, such as battery trays. Inoplastic Omnium (Levallois, France) discussed the rapid growth in Europe of plastic rear hatches on vehicles and the company's hybrid of a structural thermoset SMC inner panel and a dent-resistant thermoplastic outer panel. In addition to saving weight, the plastic's electrical transparency permits location of a car's antenna inside the door, where is it less susceptible to damage.
On the all-thermoset solution side, John Remy of General Motors revealed the design and construction processes used for the hood on the 2004 Commemorative Edition Z06 Corvette. This part combines an autoclave-cured carbon fiber/epoxy outer skin with a compression molded inner panel, produced from a mix of carbon fiber SMC and low-density glass SMC, resulting in a 33 percent weight savings over an all-SMC hood (see "Carbon Fiber Gains Traction with Automakers," CT August 2003, p. 32).
Other SMC advancements discussed at the conference focused principally on improvements in exterior quality - most importantly, the reduction of paint "pops" at the assembly plants. Budd Plastics (Troy, Mich., U.S.A.), in conjunction with resin supplier AOC Resins (Collierville, Tenn., U.S.A.) and Red Spot Paint (Westland, Mich.) reported on their tough Class A formulation, which has been adopted successfully across a broad range of Ford products with greater than 90 percent reduction in surface pops.
Interest remains high in carbon fiber as a means to save weight. Paolo Feraboldi of Lamborghini explained in depth the extensive use of carbon fiber on the Lamborghini Murcielago, which features autoclave-processed carbon fiber prepregs in most exterior body panels and the floor. Lamborghini has developed an all-composite door for the next model, which meets side-impact requirements without a metallic door beam, saving considerable weight. SP Systems' (Isle of Wight, U.K.), paper discussed the use of vacuum-cured SPRINT (SP's proprietary resin film infusion technology) for the exterior body panels of the MG Rover X-Power SV sports car, coming to market this fall.