DUSSELDORF - After being available commercially for more than 10 years, gas-assisted injection molding techniques finally are coming into widespread use. Delphi Interior & Lighting Systems, aunit of General Motors Corp., and GE Plastics spent five years developing gas-assisted molding techniques to produce what is being called the ``Superplug'' door module, a modular frame that plugs into a car door, carrying the door's window and lock operating components.
Christopher Clark, an advanced development engineer for GE Plastics, said at the Autoplas '95 conference in Dusseldorf that the Superplug com-bines 61 previous subcomponents into one frame. Clark claims that the Superplug module ``represents a quantum leap forward in injection molding technology.''
Separately, Mazda Motors Ltd. of Tokyo used the process to develop front and rear bumper moldings for its Lantis models.
Raymond Foad, sales manager for the European and Asian markets for Cinpres Ltd. of Tamworth, England, said Mazda developed the bumper with three requirements:
To mold the structural bumper parts with the bumper facing, which would make assembly and disassembly easier.
To reduce warp and distortion while producing the bumper on small molding machines, which is permitted by the lower pressures required with the gas-assist process.
And, to reduce the wall section of the bumper, leading to a reduction in overall weight.
After trying a variety of designs and modifying rib and channel placements, Foad said Mazda achieved the integration of parts with a weight savings of 37 percent for the front bumper and 24 percent for the rear.
Also, Mazda made the new bumper on a 2,400-ton injection molding press. It had used a 3,500-ton press.
Finally, Foad said, Mazda saw a 60 percent increase in bending rigidity from the new bumper compared with the old.
Clark claimed the Superplug is the first all-plastic door module. It was made with snap-fit and other complex design features, Clark said. It reduces the weight of doors by 2.2 pounds, offers a 5-15 percent savings in cost, and reduces vehicle assembly time. The Superplug is made of a 30 percent glass-fiber-reinforced polycarbonate/polyester blend from GE Plastics.
Meanwhile, Michael Ladney, president of Gain Technologies Inc. of Auburn Hills, Mich., announced Oct. 4 that he intends to strike a deal with Bauer Compressors GmbH of Munich, Germany, that will have Bauer manufacturing Gain's gas-assisted injection molding equipment in France, while Gain becomes a worldwide distributor of Bauer's air and nitrogen compressors.
Ladney said he broke off negotiations to team up with Battenfeld Machinery several weeks ago. In an interview the day before K'95 opened, Ladney indicated that Gain and Battenfeld remain at loggerheads over the failed deal. However, he said his intended arrangement with Bauer will not be exclusive.
