Realign and Secure the PTFE Hotend Liner

This procedure eliminates the internal gap where 70A TPU buckles by ensuring the PTFE tube is seated flush against the nozzle.

Tools Required: Heat-resistant gloves, nozzle wrench (or socket), and a clean, sharp razor blade or tube cutter.

Safety Precautions: Perform this procedure while the hotend is at operating temperature; wear gloves to prevent thermal burns.

1. Heat the hotend to your standard printing temperature (e.g., 220°C–240°C).
2. Once at temperature, carefully unscrew the nozzle from the heater block.
3. Inspect the PTFE tube inside the heat break. If the end is deformed, charred, or uneven, use the razor blade to cut the tube perfectly square and flush.
4. Reinsert the PTFE tube into the hotend assembly, ensuring it is pushed all the way down until it stops firmly against the internal shoulder of the heater block.
5. Screw the nozzle back into the heater block while the hotend remains hot, tightening it firmly to ensure the nozzle creates a pressure seal against the bottom of the PTFE tube.
6. Allow the assembly to cool, then perform a test extrusion to verify that the filament feeds smoothly without clicking or buckling.