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How to replace a hotend PTFE tube (MK3S+/MK3S/MK2.5S/MMU2S)

How to replace a hotend PTFE tube (MK3S+/MK3S/MK2.5S/MMU2S)

How to replace a hotend PTFE tube (MK3S+/MK3S/MK2.5S/MMU2S)
Last updated 7 months ago
How to replace a hotend PTFE tube (MK3S+/MK3S/MK2.5S/MMU2S)
 Difficulty
Moderate
 Steps
13
 Available languages
CSDEESFRITJAPL

Step 1 Getting the correct PTFE tube

Getting the correct PTFE tube
Getting the correct PTFE tube
Getting the correct PTFE tube
This guide will take you through the entire process of how to disassemble the MK3S+/MK3S/MK2.5S/MMU2S extruder, replace the PTFE tube and assemble the extruder back.
Note that the upper part of the MMU2S extruder is slightly different from the single material MK3S+/MK3S/MK2.5S, but the disassembly is the same as it focuses on the lower part.
This guide doesn't work for the MK3/MK2.5 type of extruder!!! See the How to replace a PTFE tube (MK3/MK2.5)
To obtain the new PTFE tube, you have two options:
Buy cut and chamfered PTFE tubes from our eshop
Make your own PTFE tube using this guide: How to trim PTFE tube - Original Prusa i3 printers

Step 2 Tools necessary for this guide

Tools necessary for this guide
Tools necessary for this guide
Please prepare the following tools for this chapter:
2.5mm Allen key for M3 screws
Needle-nose pliers for zip ties (optional)
Pliers are not needed, but in some scenarios, you might need them to cut the zip ties.
Apart from the mentioned tools, it is recommended getting a bowl or a small box for the screws and parts you will remove during the disassembly, you will need them later.

Step 3 Protecting the heatbed

Protecting the heatbed
Protecting the heatbed
Protecting the heatbed
Before you start it is recommended to protect the heatbed!
Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.
Make sure that:
the filament is unloaded from the hotend (remove also the spool and the spool holder)
the printer is properly cooled down
the printer is unplugged from the socket
X-axis with the extruder is slightly above the middle of the height (Z-axis) of the printer.

Step 4 Partial disassembly of the extruder

Partial disassembly of the extruder
Partial disassembly of the extruder
Partial disassembly of the extruder
Partial disassembly of the extruder
In this guide, we won't disassemble the extruder completely. Thanks to the new design it is enough to release the screws and move the plastic parts slightly apart.
Release and remove the M3x14 screw from the hotend fan.
Release the M3x40 idler screw from the left side of the extruder.
Release and remove the M3x20 (M3x18) screw from the hotend fan. Note that the fan-shroud might fall off.
Leave the other two screws holding the hotend fan in place. No need to remove them.
Release both screws, but don't remove them. We will use them to hold the extruder parts together.
Release both screws, but don't remove them. Just make sure they won't block the motor from moving.

Step 5 Partial disassembly of the extruder

Partial disassembly of the extruder
Partial disassembly of the extruder
Partial disassembly of the extruder
Partial disassembly of the extruder
Before you move any parts, make sure there is enough slack in the extruder motor cable!!!
If not, you have to cut the zip ties on the textile sleeve, open the box with electronics and make sure the motor cable is free to move.
Carefully move the extruder apart. First, pull the motor, then the lower part with the print fan.
Create a gap similar to the picture. Align the printed part holding the motor with the edge of the fan frame.
Reach for the hotend and incline its upper part towards the motor, it should slide out.
If the hotend is still stuck inside, release the screws more and increase the gap between the printed parts.
BE EXTRA CAUTIOUS with the hotend cables!!! You can break them! Use a small force to pull the hotend out. Don't bend the cables.

Step 7 Removing the old PTFE tube

Removing the old PTFE tube
Removing the old PTFE tube
No need to place the hotend in the horizontal position like in the picture. It is better to leave the hotend next to the extruder.
Press the black plastic collet.
Remove the PTFE tube from the hotend.
Throw this old tube immediately to the nearest trash bin to avoid installing it back by accident ;)

Step 8 Assembling the new PTFE tube

Assembling the new PTFE tube
Assembling the new PTFE tube
Assembling the new PTFE tube
Now it is time to insert the new PTFE tube. Note, that each end of the tube is different.
One end of the tube has "rounded" outer edge. This end must be inside the hotend.
Look at the other end, where the tube is drilled inside, the shape of the edge is "conical". This is the side, where filament enters the tube. This part must be outside the hotend.
Push the black collet in. Slide the tube all the way in and hold it!
Using the other hand pull the collet out and only then release the tube!!! THIS IS CRUCIAL for the hotend to work properly.
After you finish inserting the new PTFE tube, check all the parts are properly tightened and nothing got loose during the process.

Step 9 Reassembly of the extruder

Reassembly of the extruder
Reassembly of the extruder
Reassembly of the extruder
Reassembly of the extruder
Place the hotend back inside the extruder. Ensure the orientation is the same as in the picture with cables on the left side.
IT IS CRUCIAL to ensure the hotend fits to the extruder-body!!! The printed part is shaped according to the hotend. See the second and the third picture!

Step 10 Reassembly of the extruder

Reassembly of the extruder
Reassembly of the extruder
Reassembly of the extruder
Check once again the correct position of the hotend. Look from below the extruder. The heater block should be oriented, like in the picture.
Take a look from the side of the extruder. The nozzle should be slightly below the printed fan-shroud.

Step 11 Reassembly of the extruder

Reassembly of the extruder
Reassembly of the extruder
Carefully and slowly push all the parts together. In case of any significant resistance STOP immediately and check, which part is blocking the movement .

Step 12 Reassembly of the extruder

Reassembly of the extruder
Reassembly of the extruder
Reassembly of the extruder
Reassembly of the extruder
Tighten both screws, but ensure no cable is pinched on both sides of the extruder.
Similar for the front side. Tighten both screws. Ensure no cable is pinched.
Put back the M3x14 screw and tighten it.
If you have removed the fan-shroud, put it back in. Then fix it in place with the M3x20 (M3x18) screw.
Secure the M3x40 idler screw so its head is roughly flush with the printed part.

Step 13 It is done!

It is done!
It is done!
It is done!
Great job! You've just changed the PTFE tube in the extruder.
Heat up the printer and try it out ;)
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