Yet Another Bowden Extruder

thingiverse

This extruder, designed for use with 3mm filament and a Bowden tube, reduces print head mass by placing the tube between the extruder and hot end. Key objectives were to manage lateral loads on the gear reduction output shaft, securely mount tubes, expose the hobbed gear for inspection, and keep filament centered. Made from accessible parts, it features a 5.2:1 gear reduction NEMA 17 stepper motor, modified compression fitting, and Airtripper's fuel line-based tensioner. Mounted on a 20x20mm aluminum extrusion, this 0.1 version has been in use for four months on a delta printer. Retraction settings are the biggest challenge due to varying filament behavior. Potential improvements include eliminating the compression fitting and directly threading the PTFE tube into the filament guide, adding a fast release feature, compact design, and integral wiper. Self-explanatory instructions are available at http://thefabfor.com/yet-another-bowden-extruder/. Essential parts include a specific compression fitting, ball bearings, bolts for tensioner and motor mount pivot, flathead screws, 8mm rod, high pressure fuel line section, and appropriate drill bits and taps. Tools required are a drill press, various taps and drill bits, and a steady hand if needed.