What are the white tubes included with the MK3S used for?

What are the white tubes included with the MK3S used for?  

Active Member
I got a white tube about 5cm in length and one spare with my MK3S kit.
I don't believe I ever saw it mentioned in the assembly instructions.
What is this tube used for?
I assume it goes in the extruder assembly to guide filament?
If so, what step in the assembly instructions is this mentioned?
I have done my best to look for it...can't find it.
Posted : 29/10/2020 7:39 am
Active Member

Its a replacement PTFE Tube.


the guide how to replace this tube is here.





Posted : 29/10/2020 7:55 am
Noble Member

Its the ptfe tube that is part of the hotend assembly.  That part is pre assembled on the kits.  You can see it pictures here https://help.prusa3d.com/en/guide/5-e-axis-assembly_28536 in step 12.  Its held in place by the black plastic clip (push inwards towards the metal to release the tube , allowing it to be removed.  On the original e3d hotends sourced from e3d they come with a small clip that goes under the black locking collet to stop it accidentally going down during use.  For the life of my I have no idea why prusa dont fit/supply these.  I always fit them myself (one of the first things I printed, theres loads of them on thingiverse).  As they help stop the ptfe tube getting loose and you dont want a gap.

One end is chamfered on the outside and that end goes in first so meets the metal.  The side that sticks out/up should have a small chamfer on the inside to help guide filament into it.

Prusa's instructions for it are here https://help.prusa3d.com/en/guide/how-to-replace-a-ptfe-tube-mk3s-mk2-5s-mmu2s_21664/   

Posted : 29/10/2020 8:01 am

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