Recycling with 3D printing

Posted by Pete Danko, EarthTechling

If you believe the 3D printer hype – and not everyone does – we’ll all soon be printing out things at home. Why, exactly, isn’t clear; do we really need more generic plastic crap that would probably be better and cheaper, anyway, all costs considered, if we just bought it off Amazon?

But maybe the calculus will actually work out: A new published study finds that 3D printers could offer a less expensive way to make goods, and a more efficient way to recycle plastics than our current method of putting our emptied milk jugs and 2-liter Mountain Dew bottles out at the curb every week, with all that happens after we’ve left them there.

3d printing recycling

Researcher Joshua Pearce holds a DremelFuge chuck made from shredded plastic milk jugs. (image via Michigan Tech University)

The work was done by engineers at Michigan Technological University, and a line from a university press release sums it up nicely: “A study led by Joshua Pearce of Michigan Technological University has shown that making your own plastic 3D printer filament from milk jugs uses less energy—often a lot less—than recycling milk jugs conventionally.”

What we’re talking about here is our old friend life-cycle analysis, looking at the energy cost of something from the beginning of the process (for all components) right to the end. Cradle to grave, as they say.

On one side in this face-off was the new practice of using a milk jug made from HDPE plastic in a 3D printer – after cleaning, cutting and shredding it, then using a device to turn it into printer filament. On the other side was recycling the jug, which could vary considerably depending on the nature of the recycling program used.

Again from the release:

Compared to an ideal urban recycling program, which collects and processes plastic locally, turning milk jugs into filament at home uses about 3 percent less energy. “Where it really shows substantial savings is in smaller towns like Houghton (Mich., location of MTU), where you have to transport the plastic to be collected, then again to be recycled, and a third time to be made into products,” said Pearce, an associate professor of materials science and engineering/electrical and computer engineering. Then the energy savings skyrocket to 70-80 percent. And, recycling your own milk jugs uses 90 percent less energy than making virgin plastic from petroleum.

On the cost side – recycling vs. buying filament – the recycling was a winner, too. The stuff goes for like $36 to $50 a kilogram, Pearce said, and producing it yourself is around 10 cents. Yeah, cents. Enough to make the cost of a machine that turns waste plastic into 3D printer filament, like the $300 Filastruduer, well worth it in the long run.

* Pete Danko, EarthTechling