Recycle Bottles for 3D Printer Filament
Polyformer accepts old water bottles and similar plastic waste, processes it, and then spits it out as filament usable by 3D printers.
The first question to pop into the head of every environmentally conscious newcomer to 3D printing is: “can I use old recycled plastic as filament?” Plastic waste is a huge problem and it would be awesome if some of that waste could go towards something useful. And most of the common plastics in use today are thermoplastics that are technically suitable for 3D printing. But home recycling and filament production has long eluded the community. If we're lucky, that might change soon thanks to Reiten Cheng's Polyformer device.
Polyformer accepts old water bottles and similar plastic waste, processes it, and then spits it out in the form of filament usable by 3D printers. Water bottles are usually made of PET (polyethylene terephthalate) plastic, which can work as filament. In fact, PETG (which is PET with a glycol additive) is a very popular 3D printing filament material. Standard PET isn't ideal for 3D printing, as it gets stringy and leaves "pimples," but it can work for rough prototypes.
The main draw of Polyformer is that it looks nice—no surprise considering Cheng is a recent industrial design graduate. But we've seen many plastic recycling devices like this before and they rarely turn out to be practical. Mechanically, Polyformer is simple. After the user starts a cut in a plastic bottle and feeds it into Polyformer, the machine continues to slice the bottle into one long strand of plastic. It then uses a motor to feed that into the same kind of hot end 3D printers already use, which melts the plastic and forms filament.
But there are challenges here that it isn't clear if Cheng has solved. Most importantly, filament must be consistent to print well. It has to be as cylindrical as possible and a constant diameter. Even mass-produced filament sometimes fails to meet those standards, which results in poor print quality. Nothing shown in the beautiful Polyformer promotional photos seems to indicate that Cheng created a viable solution for this problem.
Still, if you find this project interesting, Polyformer is open source. That means that you can try building a machine yourself and even contribute to its ongoing development.