DETROIT - Imagine a world where suppliers of plastic automotive-interior components and systems would no longer need steel tools or presses.
The savings would be dramatic, about one-quarter of the capital expenses now spent for injection-molding equipment. And tooling costs, using an inexpensive epoxy resin, could be cut by more than half.
Lear Corp., one of the world's largest interior-systems suppliers, is seriously considering such an experiment. The Southfield, Mich.-based company will begin trial runs this spring from a new process that the company developed in-house.
Parts will be made using a familiar technology that Lear has updated for the next millennium: vacuum forming.
TWO PROCESSES AT ONCE
'We hope to be building headliners with it by the end of the year,' said Jack Van Ert, Lear director of advanced process development. 'We can get four times the production output per square foot than we could by compression-molding the parts.'
The company is actually developing two processes at once. Both involve forming parts from two halves of a clamshell-shaped mold, where a formed resin sheet and a natural-fiber cover skin can be melted and bonded together mechanically when the mold is closed. No adhesive is needed to bond the material.
One process, twin-shell vacuum molding, passes air into the mold chamber and then evacuates it to create molding pressure. The other, hydromolding, substitutes water pressure for the air.
Lear hopes to use vacuum forming for such high-profile interior parts as headliners, door panel substrates and the knee bolster section of an instrument panel, Van Ert said.
Vacuum forming is used regularly for smaller, interior trim panels, said Kenneth Rusch, technical programs manager with Budd Co. Plastics Division in Troy, Mich. But the process is normally not used for larger parts where cover skins are needed, he said.
'It doesn't work well with complicated geometry, where you need ribs or bosses or difficult shapes,' Rusch said. 'But all you have is a low-cost tool and no press. You don't need an expensive facility and you can get huge savings from tooling and equipment.'
GOAL: BIG INTERIOR PARTS
Budd, a large compression molder, does not use vacuum forming for the exterior body parts that it molds, Rusch said.
But Lear is gunning for those large interior parts. The savings can be significant, and production is comparatively simple, Van Ert said. Instead of bringing in a space-gobbling compression press, small vacuum-forming equipment can be hooked up easily to a 110-volt outlet.
The company borrowed the idea from the office-furniture industry, Van Ert said. That industry vacuum forms laminated, precolored film stock with plastic resin to create some office pieces.
Lear is working on gaining patents for the technology and forming partnerships with furniture companies, he said.