Ever wonder why more people are not generating Polyethylene terephthalate (PET) filament from recycled material? Currently, at Filabot, we have been working towards finding solutions to this problem and have had multiple problems. Because of the high temps and melt flows it is very tricky to get the material to extrude just right, especially with the issue of the polymer cooling around the nozzle. The die drool that forms around the nozzle can make the extrusion process even harder to achieve. Although one solution to this is to keep the nozzle heated to prevent the die drool, it is difficult to keep the nozzle insulated and achieve zero die drool. Once one can overcome that then comes the tricky solution of cooling the filament to spool. Because of the high temperatures used for extrusion, using an Airpath at 100 isn’t going to cut it. Right now we have tried multiple Airpaths and homemade waterbaths to get the filament cooled. The last issue we have had is consistent feed of material, this is due to bridging of the regrind causing output to be inconsistent. But, we are not going to let this stop us from finding a solution to recycling PET. In some of our inhouse cases we have used a mix of recycled PET with a mix of virgin PETG pellets to generate successful filament.
Another case study: https://3devo.com/wp-content/uploads/2018/04/PET-recycling.pdf