I guess these guys just won a Dyson award for this design. I don't love having to pull the bottle apart instead of automating it like the rest of the process, but I really like the rest of the overall design:
www.reiten.design

Polyformer — Reiten Cheng
Polyformer is an open-source project that aims at help solving world's plastic waste problem. It is a 3D printed machine that turns plastic bottles into filaments for 3D printers.