NEW YORK – A key ingredient of the all-new ’10 Acura ZDX cross/utility vehicle is its tightly contoured styling.

Nowhere is that more evident than the vehicle’s rear quarter, where large shoulders and a highly sculpted crease leading up to the tapered roof are reminiscent of the space between a person’s collar bones.

This design vision proved vexing to Honda Motor Co. Ltd.’s Ohio-based research and development staff. They wanted a rear-quarter side panel with what engineers call a very deep draw. Honda’s in-house manufacturer had never stamped such a large and complex single piece before.

“We gave (the design) to our manufacturer and they said, ‘We can’t do that,’” ZDX Chief Engineer Gary Evert tells Ward’s here during a media event for the vehicle. “We said, ‘That won’t work. We have to do it.’”

Jason Widmer, principal engineer-Acura, says the ZDX team considered making two panels, separating the door ring from the rear quarter panel, as is the industry standard.

“The problem with doing it in two pieces is you end up with a seam,” he says. “We wanted to keep the outside of the car looking very high-quality and very sleek.”

Weight, cost and quality also were reasons for going with a single-piece stamping.

The quest for a 1-piece panel prompted months of work.

“We went to a couple companies that do hydroforming,” a process that forms metal with fluid under very high pressure, Evert says. “But the problem with that was if you have a door ring, you can’t build (enough) pressure behind it to be able to stamp it. So, hydroforming wasn’t going to work for us.”

Until the final planning stages of the ZDX, Acura engineers still had two designs for the vehicle’s side rear-quarter, a traditional 2-piece and the 1-piece.

“We did an underground study of making the 1-piece, and that went on four or five months where we did all the simulation and prototype parts just to see if it was possible to do the openings for the doors,” Evert says.

By the time final ZDX evaluation rolled around, Acura engineers were able to bring to executives the side rear-quarter panel to a meeting and confirm the stamping could be done.

The simulation was so successful, Honda scrapped a plan to use a lubricated material from Japan, dubbed pre-foss, to cover the outside of the stamping so steel flows in the dies more easily.

“So we went through the process of doing a whole new technology and validating it for production in America,” Evert says. “But when we finally got to the time we started to make those panels, we had done such a good simulation and designed it so well, we didn’t need to use that pre-foss material. (But) we have it on the shelf if we need to use it.”

The large stamped piece, which includes the side panel and the entire door ring, at 12.6 ins. (32 cm), has a draw 50% deeper than any panel Honda has produced in the past. It is stamped on three presses in three stages.

Evert says the technology is transferrable to other models and is a demonstration of how far the auto maker’s manufacturing capability can be pushed.

“It helps us really make a bold statement in the styling, (Acura’s signature) keen-edge styling, so I would definitely say it’s going to show up in other products,” he says.

The ZDX goes on sale this winter in the U.S.

cschweinsberg@wardsauto.com