Rotational molding adopting 3-D printing

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CLEVELAND — 3-D printing is coming to rotational molding.

Nova Chemicals Corp. got into rotomolding resin in 2006, and three years later, bought a 3-D printer to develop new product ideas, such as boats and dumpsters, according to Henry Hay, Nova application development manager.

The company bought a Dimension SST 12000 printer, which builds parts in layers from CAD drawings.

Attendees at the Society of Engineers’ rotomolding TopCon 2014 heard reports on the technology from Hay and Mike Hripko, an official of America Makes in Youngstown, Ohio, part of the National Additive Manufacturing institute.

Hay detailed some Nova case studies. “Because our parts of rotomolding are so large, when you build models of then you’re going to be using scale models,” he said. That requires some design considerations, such as duplicating hinges and using two nestable parts to show double-wall construction.

You can build a model for less than $400, Hay said, but takes 88 hours. “So what it costs is time,” he said.

One product, the Cosmo-brand collapsible storage container was developed five years ago by a Nova Inspirion Ventures Inc. and is rotomolded by Plasticraft Corp. in Darien, Wis. They were designed for moving companies, but the downturn in construction came just at the product launch, Hay said.

“We did get sales both to the military, the Marine Corp. and to private movers both in Canada and the U.S.,” Hay said.

For another product, the Dumpster mate, an entrepreneur approached Nova with an idea written on a napkin: a plastic enclosure to hide a dumpster, replacing makeshift concrete and steel ones. The enclosure would have swinging doors on the front, which the truck driver would be able to open without getting out of the truck.

Nova built a model for $570, and 172 hours of time. The idea man took it to a trade show, where he secured enough contracts to justify making the molds. The mold-maker also used the 3-D printed model.

The inventor is using Nova polyethylene for the enclosure.

TopCon attendees toured America Makes after the Cleveland conference. “This technology reduces barriers to entry,” said Hripko, deputy director of workforce and educational outreach of the Youngstown center.

For example, you can buy a universal cell phone holder for a car today for $19.95, with no guarantee it will really fit. In the future, you could print one specifically for your car, for less than $5, he said.

“Anyone can now make anything anywhere, and the only things you need is electricity, material and a computer,” Hripko said.