Replace the TFM coupler

The TFM coupler is a key component of the hot end. It allows filament to flow smoothly through it from the Bowden tube and towards the nozzle. The coupler is made from TFM which is able to withstand high temperatures.

However, after extended use, the TFM coupler can degrade due to the heat. When this happens, the bottom part of the coupler can look burnt and the exit hole surface will become rough. This can increase friction on the filament, leading to extrusion problems.

It is recommended to check and replace the TFM coupler when it shows signs of degradation. If experiencing extrusion issues, it is also advised to check the coupler and replace it if necessary. The following steps describe how to correctly replace the TFM coupler:

⚠ Caution: Make sure filament is removed, the Ultimaker is turned off and power supply disconnected before you start the replacement.

✔ Tip: It is advised to perform the Atomic Method before starting this repair. Filament stuck in between the hot end parts can act like glue, making it very difficult to disassemble the parts.

Parts required:

  • 1x 2278 TFM isolator coupler

Tools:

  • 2.0 hex screwdriver
  • Blue tape
  • Print head alignment aid

Time:

  • 15 minutes

Disassembly

1. Remove clamp clip

  • Place the print head in the front-right corner.
  • Remove the blue clamp clip.

2. Remove the Bowden tube

  • Press down on the white tube coupling collet.
  • At the same time, pull the Bowden tube upwards, out of the print head.

Remove clamp clip
Remove Bowden tube

3. Remove the thumb screws

  • Position the print head at the mid-point of the X and Y axles for easier access.
  • Loosen the four thumb screws and take them out of the print head.
  • Put some blue tape around the three parts of the print head housing. This ensures that the parts stay together.

Remove thumb screws
Tape print head

4. Remove the fan bracket

  • The fan bracket is attached with two M3x4 bolts on either side of the hot end.
  • Use the hex screwdriver to remove all four bolts.

Remove fan bracket

5. Open the hot end holder

  • Loosen the two M3x10 bolts that are in the top aluminum plate.
  • Remove this plate to access the hot end parts.

Remove bolts aluminum plate
Remove aluminum plate

6. Remove the spacer and the TFM coupler

  • Take the spacer from the TFM coupler.
  • Pull the TFM coupler out of the hot end isolator.

✔ Tip: The TFM coupler fits tightly in the hot end isolator. If necessary use a hex screwdriver to push it out.

Remove TFM coupler

Reassembly

1. Place the new TFM coupler and spacer

  • Put the new TFM coupler in the hot end isolator. Ensure it is fully inserted.
  • Place the spacer on top of the TFM coupler.

Place new TFM coupler
Place spacer

2. Secure the hot end parts

  • Place the hot end holder top on the cooling rib.
  • Secure with two M3x10 bolts.

3. Attach the fan bracket to the hot end

  • Align the fan bracket with the hot end.
  • Secure the fan bracket to the hot end with the four M3x4 bolts.

✔ Tip: To ensure that the nozzle is precisely in the middle of the hole in the fan bracket, first only loosely secure each of the four bolts. Look at the bottom of the print head to align the nozzle, then tighten the four bolts completely.

⚠ Caution: If the nozzle does touch the sides of the hole in the fan bracket, the heat will spread throughout the entire bracket. This will make it harder for the Ultimaker 2+ to maintain its temperature during printing, which can lead to quality issues or error messages.

Secure aluminium plate
Attach fan bracket
Nozzle centered in fan bracket

4. Align the print head housing and the hot end

  • Remove the tape from the print head housing
  • Move the hot end upwards to align it with the housing parts.

5. Attach the print head housing to the hot end

  • Insert the four thumb screws.
  • Screw them into the bottom aluminum plate, but do not tighten them all the way.

✔ Tip: Make sure that all cables run neatly side by side and the fan wires are not behind the back two thumb screws.

Align print head housing
Insert thumb screws
Print head cable management

6. Tighten the thumb screws

  • Completely tighten the two thumb screws at the back by hand.
  • To tighten the front two thumb screws, use the calibration spacer. Place the tool in between the aluminum plates of the hot end.
  • Tighten the front two thumb screws until the tool fits securely between the plates, but can still easily be removed.

Place print head alignment aid
Use print head alignment aid

⚠ Caution: The print head alignment aid is very important to set the correct pressure on the hot end. Securing the print head too loosely may lead to leakages, while over tightening the thumb screws will decrease the lifespan of the TFM coupler.

7. Insert the Bowden tube

  • Press down on the tube coupling collet in the print head. Push the Bowden tube all the way in.

8. Ensure the Bowden tube is correctly inserted

  • Release the tube coupling collet and gently pull the Bowden tube, along with the tube coupling collet, approximately 2 mm upwards.
  • Hold the tube coupling collet up with your fingernail.
  • While holding the tube coupling collet up, push the Bowden tube down again.

9. Secure the clamp clip

  • Place the blue clamp clip around the tube coupling collet to secure the Bowden tube.

Insert Bowden tube
Fully insert Bowden tube
Replace clamp clip

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