"PullStruder" : how to make 3D printer filament from recycled plastic bottles

cults3d

This project is one of the ten finalists of Hackaday's challenge reuse recycle revamp : https://hackaday.com/2022/06/28/2022-hackaday-prize-reuse-recycle-revamp-finalists/ Hackaday's video here : https://youtu.be/PqkdHVK8vhg full details are given here : https://hackaday.io/project/185196-pullstruder-from-plastic-bottle-to-pet-filament Please do not hesitate to "like" both this video and the project on hackaday ! I saw on youtube a few videos of guys recycling plastic PET bottles into 3D printer filament spool. Finally I tried to make my own "pullstruder". https://youtu.be/1_BWXhT5Y-I You will need : - to put some pressure into a PET bottle (2 bar). This is optionnal - hot gun the bottle to remove all the "carvings" and get an "almost cylinder" : 0:20 - cut the bottle into a ribbon : 1:35 . Plans for a really good "roller cutter" are here : https://davehakkens.nl/community/foru... - you can make "cheaper" one but not as good with a simple cutter blade - build an extruder. For this first prototype, I simply drilled a cylinder of aluminium à 1.75mm diameter. - Then I made a conical shape from 1.75mm to 10mm. So that the filament can enter the hotend and is progressively curved to 1.75mm. to produce heat I simply used a cheap chineese PID controler equiped with a thermocouple sensor https://www.aliexpress.com/item/32431... - the PID is controlling a ceramic band heater : https://www.aliexpress.com/item/32999... Then I designed a winder using an old wiper motor. You will need really a lot of torque to pull the ribbon. A strong and well reducted motor is a MUST... Finally I successfully "pullstruded" my first filament. One bottle produces 6m of PET filament. 3:12 And I tried to print with this filament the gear to adapt the wiper motor to this winder ! The temperature to print must be high enough. After several failures I got a working set point at 260°C The printed part adheres very well to the bed at PETG temperature (90°C). Apart for the filament temperature, the settings are the same as regular PETG. Now for the width of the ribbon... Here is what I did : considering that a 1.75mm filament as a section of 2.4mm square considering that my bottle has a thickness of 0.25mm, then the width should be 2.4/.25 = 9.6mm I tuned my roller cutter to get (almost) this width, and you can see the result in this video ! With a hole of 1.75mm the filament when pulled has a kind of oval shape and U shape... It is 2mm wide by 1.5mm. It turns out that 2mm is not a problem for my Prusa Mk2S :-) And I believe that the section is close enough to 2.4mm^2 as the printed result is not that bad. Still some improvement to be done but for a first attempt I am quite satisfied !