Prusa Core One INDX Filament Sensor PTFE Collet

Description

29/Oct/2026: Updated with Variable Layer Heights to more defined inner teeth (embedded in project file).
See image above for the variable layer height I chose.

This is a custom-designed PTFE collet specifically engineered for the Prusa Core One equipped with the INDX filament sensor. The collet's primary function is to securely grip the Bowden PTFE tubing and prevent it from slipping, shifting, or popping out during rapid filament retractions and tool-head movements.

Stock or worn collets can sometimes break, go missing or lose their bite over time, leading to print failures or filament jams, especially in multi-material setups where the filament is repeatedly unloaded and reloaded. This printable replacement ensures a tight, high-friction lock on standard 4mm OD PTFE tubing while maintaining a smooth filament path through the sensor block.

This model was customised to fit the INDX filament sensor with templated retainer prongs. The outer prong retainers are profiled for the side wall of the filament sensor for a more snug fit.

Printing Recommendations

• Material: Nylon or Easy PA (avoid PLA as it will snap and flex is a requirement. PETG is acceptable).

• Layer Height: 0.07mm or as close to that as possible. This is for precise internal tolerances and optimal grip on the tubing.

• Infill: 100% (solid) for maximum structural integrity.

• Supports: None required if printed in the correct orientation (usually flat on the base).

• Speed: Super slow! This is a very small model, with very thin walls/prongs. I went to 3mm/s. Good things come to those that wait.

• Filament Dryness: Ensure your filament is DRY. I found that the first few cm of the filament due to being held in the PTFE tubes outside of the dryer or drybox would be brittle when printed. It's best for Nylon/PA in my opinion to purge off a few cm before you print or print a sizable skirt.

A Grogg-3D design.