A team of University of Washington students has developed a machine that can "print" large plastic objects out of garbage.

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When he was working for the Peace Corps in Ghana and Panama, Matthew Rogge started to dream of turning waste plastic, abundant and freely available, into useful objects that would solve vexing Third World engineering problems.

Sound far-fetched?

He and a team of University of Washington students have done it.

Last week, Rogge — who went back to school to become a mechanical engineer precisely to learn how to do this — and two fellow student engineers won an international competition for their proposal to turn plastic garbage into composting toilets.

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They’ve developed an inexpensive 3-D printer that can turn shredded, melted plastic waste into just about anything.

3-D printers have been around for at least 25 years, although they have become more widely available, better-known and cheaper in recent years. They use computer-aided design to create three-dimensional objects by laying down super-thin layers of a material, such as plastic, much like a regular printer lays down ink.

But until now, nobody had figured out how to cheaply build a large-scale printer that used recycled plastic as its raw material, said UW mechanical-engineering professor Mark Ganter.

“They’re amazing students just to start with,” he said of the team. “They have a very clear vision of how to marry 3-D printing into what could help a developing country.”

The unlikely trio — in addition to Rogge, the team is made up of a former Japanese major and a blacksmith — are all pursuing undergraduate degrees in mechanical engineering. They’ll use the $100,000 prize money to build low-cost 3-D printers that can make large objects, including composting toilets and rain-catchment systems, in the mountainous state of Oaxaca in southwestern Mexico, which has a large population of indigenous people.

“Not only are we addressing water and sanitation and economic needs, but we’re reducing waste,” Rogge said of their plans. “There’s just so many good things about it.”

Plastic and Peace Corps

Rogge, who is 36 and a graduate of Lakeside School in Seattle, began reading about 3-D printers during his Peace Corps years.

In Ghana, he struggled with crude tools — files and drills — to fix water pumps so they wouldn’t leak. At a later assignment in Panama, he wasted hours trying to resize pressure regulators to make a gravity-flow water system work properly.

“Time and time again, I needed things I couldn’t buy,” he said.

Rogge believed 3-D printers held the potential to crank out custom-designed parts needed to solve engineering issues, and he thought waste plastic could serve as the raw material to produce them.

So he returned to Seattle and began working on a mechanical-engineering degree at the UW, all the while eager to finish prerequisites and begin taking his first course in 3-D printing.

When he met Ganter, the professor encouraged him to establish a 3-D printing club. And Rogge started recruiting members with a kind of infectious enthusiasm that spread through the department. The club now numbers about 50.

Rogge formed a small team with Bethany Weeks, 26, a West Seattle High grad and former Japanese major who switched to mechanical engineering, and Brandon Bowman, 28, a Ballard High grad who has worked at a recycling plant and as a journeyman blacksmith. Together, the three won the London competition.

“This is not an average group of students,” Ganter said. “This is a group of people who came to the university with a whole pile of skills. … It’s a delight to work with them.”

Building “Big Red”

They have had two breakthroughs.

The three figured out a process to melt down and create filament out of recycled plastic that can be used in conventional 3-D printers.

And they also built a large-scale, inexpensive 3-D printer they nicknamed “Big Red” using a salvaged piece of machinery from the UW’s machine shop, the motor from a drill and a plasma cutter originally intended to make precise cuts in metal. The machine can be fed shredded plastic directly, through a hopper, to make objects.

The plastic they use — it’s called high-density polyethylene, or HDPE, and is the stuff that milk jugs are made of — is “the worst material to deal with for 3-D printing because it doesn’t stick to itself,” Ganter said. It also shrinks by about 2 percent when it cools.

Over the summer, they used Big Red to print a canoe-shaped boat out of 250 shredded milk cartons, and entered it in the Seafair Milk Carton Derby at Green Lake. They started printing the boat three days before the race, working late at night because the drill was so loud.

“We threw them for a little loop,” Rogge said of the milk-carton-derby judges. “We called them beforehand — we said, ‘It’s not going to look like your standard milk-carton derby boat.’ And when we showed up they said, ‘We don’t think you can actually race that boat.’ I don’t know what they were expecting.”

The boat is the largest object they’ve created with the 3-D printer. After their success in building a floatable boat, they began readying a proposal for the London competition.

“They are clearly a group of young people with vision, a strong skills mix and the potential to actually make the project work,” said William Hoyle, by email from London. Hoyle is the chief executive of the charity Trade4all, which sponsored the competition. As part of the winnings, Trade4all will help the group put together a business plan.

“We’re confident we can put together a machine like this that will be in the $3,000 price range,” Rogge said. “The equipment we’re developing — a few thousand bucks, and you’re in business.”

They are planning to work with a nonprofit, Water for Humans, that will need 10,000 composting toilets over the next 10 years to use in Oaxaca.

Rogge said they are forming a business, rather than starting a new nonprofit, because a business “has to be designed to survive. Their survival isn’t contingent on handouts from other places. That’s a good thing.”

They’ll also need to raise more money to start the venture, but Rogge is confident they will find investors.

“This project has so much potential to do good,” Weeks said. “What we propose is a double whammy, by tackling the waste problem and using it to create solutions for clean water and sanitation.”

Katherine Long: 206-464-2219 or klong@seattletimes.com. On Twitter @katherinelong.

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