Hydroforming is essential to the Kappa platform that underpins the Pontiac Solstice. According to Jim Queen, vice president, GM North America Engineering, the hydroformed frame rails are just the tip of the iceberg. The body panels themselves—especially the curvaceous section behind the cockpit that encompasses twin peaks behind the headrests—would not be possible to produce in steel without the use of sheet hydroforming.
"There were other materials and processes we could have used to produce these panels, but we would have missed our targets," says Queen. These included the use of composites and quick plastic forming of aluminum sheet. However, both fell short of hydroformed steel sheet in terms of strength and cost. "With the low production volume slated for the Kappa platform," says Queen, "we could stretch a bit in terms of design, materials, and processes." And gaining more experience with sheet hydroforming was another plus for this process. "We have people working diligently on moving sheet hydroforming toward high-volume production, just as we do with quick plastic forming of aluminum," says Queen. This focus is necessary, he insists, if GM is to give its customers stand-out designs at competitive costs in the coming years.—CAS