FINDLAY, OHIO — In its quest to improve part quality, Whirlpool Corp. has folded gas-assist molding techniques into its entire dishwasher line for North America and plans to take the process further in the next several years.
The Benton Harbor, Mich., company, considered one of the world's two largest makers of dishwashers, shifted production at its Findlay plant last year to a special gas injection system for certain models. Now, the company plans to roll out the system for all models next year.
That production change has made Whirlpool one of the first — if not the only — appliance makers to embrace a gas-assist system in large production volumes, according to officials at the Findlay plant.
The Airmould gas-assist process, installed by Battenfeld of America Inc., will be used to make sections of a front control panel. The Findlay plant, Whirlpool's sole North American dishwasher center, churns out 2 million Whirlpool, KitchenAid and Kenmore units annually.
The plant, which runs around the clock at full production, had been known for a bevy of other innovative processes to mold its thermoplastic dishwasher parts. They include the use of stack molding to turn out dishwasher door liners and a new injection press fitted with a servo-electric screw drive to make some of its plastic tubs.
That willingness to try new techniques makes the company a standard-bearer in the manufacturing arena, said Battenfeld of America President Wolfgang Meyer.
The West Warwick, R.I.-based supplier of injection presses has worked with Whirlpool on developing the new processes.
``They have never been afraid to try new things,'' Meyer said.
Now, the manufacturer wants to expand its gas-assist process to other parts of the dishwasher console.
But outside intervention is needed before gas assist can grow, said John Vance, plastics process lead engineer at the Findlay plant.
``The panel area shadowing the [dishwasher's] electrical controls has not received approval yet from [Underwriters Laboratories Inc.],'' Vance said. ``We'd like to get that approval before we redesign consoles on new models. That way, the entire console would be fair game for gas assist.''
Underwriters Laboratories, the Northbrook, Ill.-based product research company, previously had approved using gas assist for panel sections farther from the dishwasher's electrical system. Now, Whirlpool would like to expand that to include the whole front panel.
First, Underwriters Laboratories must test an entire, gas-assist-produced console for both flame- and impact-resistance before giving it a UL stamp of approval, Vance said.
In October, Whirlpool gave UL a prototype part of the panel, which uses a special PVC material made by Geon Co. of Avon Lake, Ohio. Both Geon and Whirlpool are confident the tests will prove successful, said Thomas Buckleitner, the Findlay plant's director of support operations.
``We wouldn't mind having the result by the middle of next year,'' Buckleitner said. ``But it's nothing we need now. It's more for what it will help us do in the future.''
No timetable has been given for UL's results or for a further expansion in Whirlpool's gas-assist capabilities.
The Whirlpool plant, a vast, 1.03 million-square-foot facility, underwent a conversion to plastics processing in 1989 when the company started producing plastic tubs instead of those made from porcelain enamel.
The $100 million expansion led to the installation of 29 injection presses with a clamping force ranging from 34-3,850 tons.
That year, the company also adopted a stack molding system for its door liners to save floor space and production costs. Both the door panels and the tubs are made from 20 percent talc-filled polypropylene.
The custom-designed stack molding system, which uses three specially designed, Battenfeld 1,650-ton presses, injects plastic through a central hot-runner manifold into two, stacked mold cavities.
With two dishwasher doors in production simultaneously, production rates have doubled, Vance said. Each machine, built in an L-shaped configuration, only costs 13 percent more than a typical horizontal injection press, he added.
In January, Whirlpool also added a new 3,850-ton BA-T press containing a special screw drive separated from the press's hydraulic system.
The hybrid electric machine, one of the first servo-electric screw-drive machines sold in North America, is used by Whirlpool to make the tubs.
Those energy-efficient units have lowered operating costs, reduced oil consumption and eliminated the need for a separate filtration and cooling system, said Whirlpool engineer Bob Ebert.
The company also uses five other, hydraulically operated 3,850-ton presses to make the tubs.
Yet, the biggest move could be in control consoles. To date, Whirlpool has outfitted eight of its larger presses, ranging from 3,850-4,000 tons, with the Airmould gas-assist equipment.
The process, which uses nitrogen gas as holding pressure, allows the plant to build thin parts as wide as 20 millimeters, Vance said.
``The main thrust is aesthetics,'' Buckleitner said. ``We saw the potential of gas assist in Europe and were encouraged that we could make parts without as many flaws in their center area. On the customer side, that can only help our image as we make better-looking parts.''
By using gas assist, Whirlpool has eliminated sink marks, distortions, warping and other blemishes, Vance said.
To do the work, two compressor modules, using nitrogen bottles, inject the gas into fixed needle points on the mold. A pressure regulator controller installed at each injection point helps lower packing pressure.
The gas then moves through a channel on the front panel, which features the dishwasher's displays and switches.
The company first used gas-assist technology on its KitchenAid line in 1996, before adding it to high-end Kenmore models this year.
Next year, Whirlpool plans to incorporate it on virtually all its exterior panels, except for those parts nearing the end of their model life and needing a redesign, Vance said.
Whirlpool, the world's largest maker of home appliances, recorded $8.7 billion in sales in 1996. The company employs more than 40,000 people worldwide.
The Findlay plant has about 1,750 employees and distributes eight dishwasher brands in the United States, Canada and Mexico.