After finding out that SPH doesn't recycle its waste plastic from the 3D printers, I wanted to do something about that. Recycling these plastics is possible, and with enough care taken to sort them, they can be reused for 3D printing with results comparable to original filament. The extrusion is then carried out with an Artme MK3.

Most of the input material is failed 3D prints, design iterations, and support material. That needs to be sorted for a high quality result, removing impurities and other types of plastics.

One difficulty for reaching a good quality result is purity: PLA and PETG need to be reliably separated. After shredding into granules, the material is extruded into 1.75+/-0.03mm filament. This is comparable to Prusa's commercial PRUSAMENT at 1.75+/-0.02mm.