After you've scrawled your name on the gizmo in the UPS carrier's hands, you race inside with your package, eager to toy with your latest electronic device. Open the box and you are sure to find a good deal of packaging, likely "expanded polystyrene," often referred to as "Styromfoam." It caressingly surrounds the product, holding it snuggly in carefully designed slots and cavities, protecting it from the hazards of travel from retailer to your door.
But if you have the courage to open the gizmo itself to take a look at how its guts are put together you'll find something else. Though the entire item was held in cushioning foam, the gizmo's components are harnessed to its chassis by fasteners and screws with sheet metal and hard plastic.
The molded foam would protect the parts of our electronics inside their plastic or metal boxes. Image: Sonoco
So why not toss out the extra hardware and put the foam on the inside?
The folks at Sonoco Protective Solutions, based in Hartsville, SC, are doing just that, for products as varied as desktop computers, medical devices, and automotive parts. They can cut a block of foam and carve it out to hold any and every component inside a product.
The benefits of doing so are immense: There's a reduction of weight; an increase in durability; a savings in outside packaging; and a savings that comes with the elimination of parts that are for attachment purposes only. "When people open it up and look at the simplicity of it, they say 'Ok, I was going to have brackets and extra parts and walls for this stuff, and I don't need that anymore,'" says Rob Cole, director of Sales at Protexic Brands, now part of Sonoco Protective Solutions.
The material Cole's colleagues use is not expanded polystyrene, but the more durable expanded polypropylene. It's heat resistant, completely recyclable, and can be made as hard as wood. What was once held by screws can be snapped into form-fitting cavities. Wires can run along excavated canals and are held in by tabs—instead of having to be painstakingly threaded, they can be pushed into place in an instant.
The foam can be used for metal wire frame or electrical wiring harness. Image: Sonoco
Another advantage is the ability—and cost effectiveness—of repeatedly editing the design to maximize efficiency. Steam chest modeling makes multiple iterations simple and keeps the number of tools needed to a minimum.
Air channels can be designed and redesigned to snake around components to make an effective and compact cooling system. As the material is flexible, tolerances needn't be as tight as they would be on a traditional chassis. And, of course, designers needn't include additional shock absorbency into their products' layouts.
So why don't we see expanded polypropylene on the inside of every electronic box on the market? "Everyone's been taught the same thing," says David Meeker of Neoteric Product Development, who, with Cole presented The Advantage of Molded Foam in Product Design at this year's International Forum on Design for Manufacture and Assembly in Providence, RI. "Look at a muffin fan, it comes to you with four holes with screws—how else would you mount it? There's no other way of thinking about it."
They can cut a block of foam and carve it out to hold any and every component inside a product including desktop computers, medical devices, and automotive parts. Image: Sonoco
In school, young engineers are taught how to deal with tensile strength in a structure, not compression. "The foam can support a lot of weight if loaded properly," says Meeker. "But people don't think of it that way. That's the big problem, getting people to think outside their training."
Switching to foam is a seemingly radical change for any company and even those considering it may keep putting off the change indefinitely. Until they see foam insides of a competitors product. "They open it up and they say 'Hey there's no fasteners in this thing?" says Cole. "They realize their goose has been cooked—suddenly my phone rings."
For some products, a foam interior is not practical. Cell phones, for instance, have been slimmed down about as far as they can go. But about 25 percent of the businesses that see how the foam works—how simply parts snap into place—end up using it. Cole suggests that manufactures divide their list of materials into two groups: "There are all the parts I've got to have and then there are all the parts I have to have by nature of my current design." Then they can try imagining the latter list vanishing into the ether.
"After they take the fist plunge," says Cole, "It's like 'Why haven't we done this before?'"
Michael Abrams is an independent writer.
They open it up and they say 'Hey there's no fasteners in this thing?' They realize their goose has been cooked.
Rob Cole, director, Sales, Protexic Brands (now part of Sonoco)
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