After experiencing disappointing results with recent large family sedan offerings such as the Five Hundred and the latest Taurus, Ford’s management was determined to make sure that the 2010 Taurus SHO was sufficiently exciting—beyond just its twin-turbo, 3.5-L, EcoBoost V6 engine—to justify the “super high output” badge.
To Lon Zaback, Interior Design Manager for the new model, part of meeting the mandate meant looking to incorporate into the SHO’s passenger cabin “aesthetic design enablers—key details that motorists see and touch every day that signal high quality.” Out of reach, unfortunately, was luxurious hand-wrapped and -stitched leather interior paneling, a costly feature that he said “exudes high quality and craftsmanship.”
That all changed in late 2006 when product development team members showed him examples of a novel polymer production process that could yield interior skins with highly durable surfaces that closely resembled leather.
“When we first saw the spray-cast polyurethane material—a couple of faux-leather purse samples, in fact—everyone said: ‘Look at this detail!’ They had a surprisingly convincing look and feel,” Zaback recalled.
“We had found a unique spray urethane process that not only delivers very high durability to maintain long-term appearance but also outstanding product appearance,” said Matt Quam, Design Release Engineer on the project for Ford. When spray cast in molds, the stretchy plastic can hold very small external and internal radii.
“Spray urethane has an ability to handle fine detail to an extent that most existing cast-skin technologies cannot match,” observed John Johnston, Product Development Engineer for ACH, the Ford-managed internal engineering company. “It’s flexible enough to get undercuts and features with negative draft angles that otherwise would typically lead to die lock,” he noted.
With Zaback’s support, Quam “took the technology to the chief engineer, asking that we move from a standard cast-skin-type process to the foam-in-place spray urethane process for the interior door panels,” he recounted. “They looked into it and we were surprised to find out a little later that they were as excited about the process as we were.”
The team—which included members representing Ford, ACH, and Tier 2 supplier FRIMO Inc., mold- and tool-making specialists based in Wixom, MI—was abruptly tasked with an accelerated program to develop the upper inserts of the SHO’s interior door panels as well as various “substrate sections” of the instrument panel.
“It was originally a 2011 program, but it was moved up a model year, so everybody was suddenly under the gun,” Zaback said.
“We worked as one integrated team,” stressed Mike Lee, Engineering Product Manager for ACH. “It took a lot of coordination to get the technology from approval to plant floor in less than two years.”
The mandrel development process started with a leather craftsman who hand-wrapped the individual offset panels for each door with about eight pieces of individually cut and stitched pieces. “Then we took a cast of the masters,” Lee explained, “and after several castings we were able to get to a nickel tool that accurately copied most of the fine details of the stretched leather.”
Next, the team manufactured the urethane panel skins by first spraying mold-release into the nickel shell tooling, followed by a colorant. (Two-tone capability is available with the addition of another hue, Johnson explained.) Afterward liquid polyurethane was sprayed into the open tool. Curing at ambient temperatures solidified the skin, which was only a few millimeters thick. The plastic was at this point peeled out of its mold and placed in a clamshell tool that was lined in the rear with a hard plastic backing substrate. Technicians then dispensed liquid foam into the gap between skin and backing, which thereabout expanded to fill the breach, providing a soft cushion.
The entire fabrication process takes around a minute.
Zaback said that humans generally need “a visual gap of around 4 mm” between adjacent objects to differentiate them. “The spray urethane material fills every nook and cranny, providing details, say a radius or corner, as small as 2 mm,” he reported.
“Overall, it’s a cost-effective process that provides good value,” stated Johnson, who added that it was particularly satisfying “to deliver what the design people wanted” on time and at cost.
“The beauty is that the excellent durability and look doesn’t cost any more from the manufacturing viewpoint,” Zaback noted, acknowledging, however, that “it does take a lot more groundwork and engineering development time to set up.”
Now that Ford has invested time and capital in the successful process, he concluded: “You will probably see it used elsewhere in our products.”