PETamentor 3 - Full-Color-Filament

PETamentor 3 – Full-Color PET Bottle Filament System

Important information below; read the entire description!

Warning: this model is in active development. Revised versions are released periodically. Additionally, I am currently building print profiles for the filament made!

Changelog

• 0.4mm nozzle profile added. Do not change these settings, as doing so will (and I mean Will) result in clogs!

For bambu users: Bambu Labs' restrictions on custom filament and machine profiles, which disallow custom filament in print profiles, print profiles can be found in the downloaded STL and CAD files.

 The assembly instructions PDF can be found in the other files section

Introduction

PETamentor 3 is the next evolution of the open-source PET filament machine, designed to turn everyday plastic bottles into high-quality 3D printing filament—now with full-color printing capabilities.

Building on the simplicity and efficiency of previous versions, PETamentor 3 uses a streamlined process: PET bottles are cut into a continuous strip, fed through a heated nozzle, and formed into consistent filament ready for 3D printing. The system remains accessible and DIY-friendly, using widely available components such as a motorized puller, adjustable cutter, and temperature-controlled hotend.

This new version introduces enhanced control and precision, allowing for full-color filament production, enabling full-color prints (not just glass see-through ones) and expanded creative possibilities without relying on pre-manufactured filament. Combined with adjustable strip width and improved extrusion stability, PETamentor 3 delivers more consistent results across a wider range of bottle types.

Like its predecessors, PETamentor 3 emphasizes sustainability and cost-efficiency—transforming plastic waste into usable filament while reducing reliance on commercial spools. The open design encourages customization, experimentation, and community-driven improvements.

Whether you're prototyping, experimenting, or building eco-conscious projects, PETamentor 3 offers a powerful, low-cost way to produce your own filament—with color.

A note on the types of bottles that are able to be used

So far I have only been able to get pop and cup bottles to work, but that leaves out one of the biggest sources of cuttable PET: cheap plastic water bottles. Their non-uniform strips create a host of problems at the extruder, such as thermal lag and extreme diameter swings. The strip thickness controller tries to solve those problems by eliminating the non-uniform geometry through low-temp thermo-forming; However, I discovered to my dismay that such a device simply pushes the plastic outward and creates large variations in the strip width. To solve this I found three solutions: cut the strip with fast moving and dangerous saw-blade cutting jig (an 80 watt motor with two pizza-cutter-like disks, buy Nichrome 20/80 wire and heat the wire up to ~2000F and utilize quick-pull heat-based cutting, or some how control open air PET crystallization at the upon reentering the glass transition state. The last option looks promising as the filament diameter (1.85-1.97mm) tends to be larger than the nozzle diameter 1.75-1.8mm, so increasing the length of nozzle that touches the filament, such that the filament completely cools under pressure and does not expand. This last option would need a part that would have to be machined on a lathe (cost 3000-20000$), unless a mass manufactured part is found (I am open to suggestions.) However, I will still machine one myself and obseverb its results.