Recycling Bambu Poop Into New Filament

3D printing waste can become quite excessive, especially if you're doing multi-material or multi-color prints. There isn't any good way to avoid that entirely, but the massive success of Bambu Lab and their AMS systems have made this issue more apparent. Those tend to produce quite a lot of "poop" in the form of purged filament, which can equal or even exceed the amount of material in the actual printed part. To find a solution, Stefan from CNC Kitchen experimented with filament recycling to reuse the waste material.

In theory, recycling 3D printer filament should be easy. That filament is just thermoplastic, which can melt and then solidify as needed. But this is a big challenge in reality. Part of the difficulty comes down to getting "pure" material without any contaminants—including other kinds of thermoplastics used for filament. And unless you separate waste material by color, you're going to end up with a bunch of colors mixed together and that will produce a brown filament.

Stefan solved the first problem by collecting only PLA from his Bambu Lab printer. He then ran that through a machine that grinds the poops up into tiny shreds. Those fine granules went into a bin with a strong magnet to collect any ferrous particles that might have ended up in the mix.

3DEvo sent Stefan one of their Filament Maker Composer machines, which were designed specifically for manufacturing small quantities of filament from pellets or shredded plastic. Stefan found that he was able to turn his shredded waste into filament, but that it wasn't uniform enough to be usable. The variation in diameter proved to be too great to achieve acceptable results.

Stefan suspected that the problem was inconsistent feeding caused by the irregular size of the shreds. So he put the recycled filament through a pelletizer machine, then ran that back through the Filament Maker Composer. The results were better, but still weren't good enough.

Then Stefan had a revelation and determined that moisture might be the real problem. Even PLA absorbs some moisture and that causes unpredictable extrusion. After thoroughly drying the waste and then the shredded plastic, Stefan ran it through the Filament Maker Composer—no pelletization needed.

That was a success. The recycled filament was fairly consistent, with diameter variation well within acceptable margins. Stefan's test print with that filament, a Halo Master Chief helmet, turned out great. Not many people can afford a 3DEvo Filament Maker machine, but Stefan's tests prove that home filament recycling has potential and that it could become viable if costs come down.