'Printer Poop' Is a Real Plastic Waste Issue… But Here's How To Recycle It

Tiny shards of multi-colored plastic that are the result of 3D printing filament

The invention and accessibility of 3D printing has been an amazing help to humanity. 

Whether printers are using their machines to extend the lifespan of damaged goods, personalize toys for children with disabilities, or even build schools and bridges, the power of 3D printing is a great example of using creativity for good.

But there is still a fundamental problem when it comes to multi-color 3D printing: printer poop.

For the 3D printing novices, “printer poop” is the plastic waste that is purged from a 3D printer’s nozzle when changing filaments. 

A 3D printed helmet and a bowl filled with wasted 3D print filament
Stefan Hermann's 3D print project next to the "printer poop" it created. Photo courtesy of Stefan Hermann/CNC Kitchen

When folks create multi-colored designs, these “purge poops” come out of the printer in technicolor clumps and strands (try not to think too much about it), which usually cannot be reused or recycled.

So, Stefan Hermann of CNC Kitchen, an educational 3D printing channel on YouTube, decided to try his hand at eliminating his printer poop through new recycling methods.

What spurred Hermann’s experimentation was his experience generating over a kilogram (that’s more than two pounds) of printer poop after creating a 500-gram multi-colored print. That’s a lot of 3D doo-doo.

“Instead of throwing them in the trash, I wanted to use some of my collected filament poop and make new filament from it,” he says in a YouTube video.

In order to recycle his 3D printer poop, he used his filament extruder, which turns plastic pellets and other raw materials into filament. However, the texture of printer poop doesn’t exactly lend itself to the normal extruding process, so he had to shred his waste material instead.

Another key element is ensuring that the printer poop is not cross-contaminated with other plastics or water. 

“Cleanliness is of utmost importance,” Hermann explained. “Anything that’s in the shredded material will later land in our filament.” 

This is important because various plastics have different melting points, meaning a mis-match of plastic materials could render the new materials useless — or damage and clog 3D printer nozzles. 

A cardboard box full of blue, green, black, and white "printer poop" or 3D print filament waste
Photo courtesy of Stefan Hermann/CNC Kitchen

Water and moisture, on the other hand, can make the filament inconsistent, which results in jammed printers. 

Ultimately, Hermann found that the best source of printer poop for recycling was the waste that was freshly purged from a print run.

And, as with any mix of all kinds of colors, the results weren’t exactly … vibrant.

“Unfortunately, we probably can’t expect a rainbow-color filament coming out of the extruder, but rather a mix of all colors that we’ve shredded,” Hermann reminded viewers. 

“And what do we get when we mix all of these colors? Yes, exactly: poop brown. Which is kind of on-theme if we remember that this used to be printer poop.”

After running the waste material through the extruder a couple of times and making adjustments, Hermann was able to create a decent, usable filament from recycled printer poop. And it even turned out as more of a green color than brown.

“I had no hiccups at all and ended with a very nice and clean print. I could see tiny variances in the extrusion rate, but other than that, it seemed to be a well usable material made from 100% 3D printing waste,” Hermann exclaimed. “Remarkable!”

Hermann used a number of commercial-grade supplies to test out these solutions, which may not be in the price range for at-home 3D printers.

However, his proof of concept shows great promise in recycling printer poop and eradicating huge amounts of plastic waste from the 3D printing world.

Header image courtesy of Stefan Hermann/CNC Kitchen

Article Details

November 7, 2023 2:18 PM
An overhead view of a cargo ship on water, with multi-colored peices of cargo.

Cargo ship emissions cut 17% in new trials — all thanks to one shockingly simple change

Cargo ships guzzle fuel, especially when they’re left idling at ports, unable to offload their goods. An incredibly easy solution could change that.
Two people standing with their reflections on the ground

New study finds algorithms help people recognize and fix their human biases

Algorithmic bias can also be used to reduce human bias. Algorithms can reveal hidden structural biases in organizations.
No items found.

Want to stay up-to-date on positive news?

The best email in your inbox.
Filled with the day’s best good news.