Beginning with Job 1, the '02 Cadillac Seville will receive a new rear bumper module that replaces a foam energy-absorbing layer with a new injection molded energy absorber. The module is also being added to theWindstar minivan as a running change.
The system was developed by LDM Technologies Inc., Auburn Hills, MI, which also will supply the entire rear bumper module on a just-in-time basis to the Hamtramck, MI, plant where the Seville is assembled.
William Kessler, an LDM senior vice president, says the development process took about two years. The LDM system is a sandwich module that has an energy absorber section that fits between the rear bumper fascia and an aluminum impact bar. The energy absorber has dozens of crush cans, each 3/4-in. in diameter and nearly 2.0 ins. long. Upon impact, the crush cans collapse and air rushes out of them. The cans have a memory and after impact regain most of their original shape.
Stuart Brown, a GM technical integration engineer for bumpers, says about 80%-90% of the original shape comes back. But he says some denting will show in severe low-speed impacts. He says the performance of the energy absorbing cans equals that of foam.
Mr. Brown says the LDM system saves about half a kilogram (1.1 lbs.) in weight and roughly $2 per car. The LDM device is said to absorb 15% more energy in the same amount of space. However, Mr. Brown says GM's low-speed 5-7 mph crash tests do not confirm that on the Seville. “With a new vehicle that might be true.” He also says no decision has been made on whether to use LDM's injection molded energy absorber system on other models. “There are a number of companies that make similar systems and all of those are being considered for possible use by GM,” Mr. Brown says.
LDM assembles the entire fascia and energy absorber for the Seville. It also purchases rear parking aid sensors from RobertGmbH that are installed in the bumper.
LDM is a private company that is a Tier 1 supplier to carmakers. Mr. Kessler declines to reveal annual sales or the value of the GM contract. LDM has 4,500 employees and 26 manufacturing facilities in six countries. Mr. Kessler says LDM has six major competitors. He ratesInternational Inc. as the biggest in the segment, but says LDM is bigger than Venture, next on the list.