Steve Otto
Design & Fabrication
Los Angeles, CA
P001 → TurtleForge
TurtleForge is an ongoing project focused on designing and building a machine that recycles discarded PET shipping strap into 3D printer filament. Follow our progress and updates on our
website | instagram
TurtleForge uses a total gear reduction of approximately 132:1, incorporating a globoidal worm gear to help the stepper motor generate enough torque for pulling the shipping strap through the nozzle.
The level winding mechanism is synchronized with the spool to ensure newly produced filament is wound evenly and consistently.
This timelapse shows the level winder in action over 13 hours, producing 600 grams of filament. TurtleForge gets its name from its slow and steady pace.
The custom heater block houses a heater cartridge and thermistor to maintain the nozzle at a temperature of 225°C.
An aluminum sheet metal heat shield was fabricated to prevent accidental burns from contact with the heater block.
TurtleForge uses a modified 3D printer nozzle, drilled to the desired filament size and featuring a chamfered inlet to improve strap forming.
The aluminum spool sides were cut on a waterjet machine and polished by hand to a mirror finish.
TurtleForge is powered by a 3D printer control board connected to a Raspberry Pi running custom Klipper firmware. It operates using custom G-code to manage the heaters and motors.
A rotary encoder sensor monitors material runout and detects downstream failures during operation.
Part of the material handling system, a splitter with a rotary blade cuts the strap to the correct width before it is formed into filament.
Tensile tests show that our PET filament has 133% the strength of its commonly available PETG counterpart.
TurtleForge is a work in progress, with plans to publish it as an open-source project.