How to check and replace the TFM coupler on the Ultimaker 2+ Connect

The TFM coupler is the white part in the Ultimaker 2+ Connect hot end. The coupler is a consumable item that wears over time and slowly changes shape on the inside due to heat and pressure in the hot end. Eventually, this will cause friction to the material that has to pass through and causes under-extrusion.

If you are experiencing extrusion problems with your Ultimaker 2+ Connect, especially after many printing hours, it is recommended to check the TFM coupler. If it shows clear signs of wear, replace it to improve your printing results.

This page explains how to disassemble the print head to reach this component. 

Tip: You can also download these instructions as a PDF guide.


  • 2.0 mm hex screwdriver (a torque screwdriver (0.5 Nm) is recommended)
  • 2.5 mm hex key
  • Print head calibration aid
  • Blue tape (recommended)
  • Nozzle alignment tool (recommended)

Tip: The STL file of the nozzle alignment tool can be downloaded at the bottom of this page.

Notes before you start

  • Clean the hot end with a cold pull before starting this procedure to remove all material residue from the inside of the hot end parts. This makes disassembly of these parts easier
  • Ensure the nozzle has completely cooled down to avoid a risk of burns
  • Unload the filament from the print head and turn off the printer before you start the disassembly
  • While disassembling the print head, make sure to keep all small parts, such as the bolts, somewhere safe so they don't get lost

Disassembly instructions

Remove-Bowden-tube.jpg Print-head-screws.jpg
  1. Remove the clamp clip and take the Bowden tube out of the print head
  1. Use the 2.5 mm hex key to remove the four long bolts from the print head


  1. Gently lower the hot end assembly

Tip: Use some blue tape to keep the print head housing parts together

  1. Use the 2.0 hex screwdriver to remove the two small bolts on either side of the hot end assembly to loosen the fan bracket


  1. Next, remove the two bolts at the top of the hot end assembly and take off the top plate
  1. Place the metal spacer aside and you can now pull the TFM coupler out of the hot end isolator


This image shows the difference between a new and a used coupler. If the edge at the bottom looks burnt, frayed, or deformed, replace the coupler with a new one.

Reassembly instructions

Insert-TFM.jpg Spacer-and-hot-end-holder.jpg
  1. Firmly push the new TFM coupler into the hot end isolator
  1. Place the metal spacer on top and align the aluminum plate. Secure it with the two M3x10 bolts
Remove-fan-bracket.jpg Nozzle-centered.jpg
  1. Loosely attach the fan bracket assembly with the four small M3x4 bolts, but make sure it can still move slightly
  1. Ensure that the nozzle is precisely in the center of the hole in the fan bracket before tightening the four bolts completely

Tip: Use the nozzle alignment tool

Align-print-head-housing.jpg Calibration-aid.jpg
  1. Remove the tape, align the housing, and insert the four long screws. Don't tighten completely and don't pinch any wires
  1. Place the print head calibration aid between the two aluminum plates of the hot end assembly
Tighten-with-aid.jpg Remove-Bowden-tube.jpg
  1. Tighten the four long screws until the tool fits securely between the two plates, but can still easily be removed. This tool ensures the correct pressure on the hot end parts
  1. Insert the Bowden tube into the print head so that the marker is no longer visible and secure the tube with the clamp clip


After replacing the TFM coupler, you can now turn on the printer again, reload your material, and run a quick test print.

Tip: This process may have caused a small change in the height of the print head and thereby the position of the nozzle. Level the build plate to ensure that your first layer adheres properly to the glass build plate.


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