Notifications
Clear all

Shortening PTFE tubing  

  RSS
patrick.c3
(@patrick-c3)
New Member
Shortening PTFE tubing

I have an upgraded MK2s MMU. I built an enclosure for it so I could print ABS ect... In doing so I had to redesign the extruder holders so the extruders can except the filament almost vertically from the top of the encloser. My issue is that now the PTFE tubing that goes from the extruder to the multiplexer is a little to long. Can I cut it shorter? Will it mess up any preprogrammed settings. If so can I change those setting in order to except shorter PTFE tubing?

Posted : 07/03/2018 2:53 am
Steve
(@steve)
Estimable Member
Re: Shortening PTFE tubing

It will. They are expected to be of a certain length.

robert.g14 found that out the hard way:


<snip>
However, I failed to pull two of the PTFE tubes out of the old QSM fittings so simply cut them off - MISTAKE! (Never built a Bowden machine before).

Next tried to print one of the supplied objects - a gear ring. This failed to change colour after several layers and began 'air printing'. Time to try something simple to find out what was wrong.

<snip>

Then I realised that by shortening two of the PTFE tubes feeding into the Multiplexer by 11mm, I had made a mistake. The machine expects these to be a certain length when it is feeding in the filament ready to print. Two new lengths were cut to the correct length and installed (I now know to press the end of the QSM fittings to release the PTFE tube!). This cured the problem and I was able to print the four blocks.

MK3S / MK2.5S-MMU2S / Ultimaker 2+

Posted : 07/03/2018 6:59 pm
JoanTabb
(@joantabb)
Moderator
Re: Shortening PTFE tubing

There is a trade off between function and convenience.

The reason the extruders face upwards is to reduce the bending radius in the ptfe as the extrudur reaches the top of the printer frame if the bend is too tight it will restrict the passage of filament in the tubes.
If the motor outlets point vertically at the extruder. The ptfe will not be able to track the extruder as the model height increases.

I mounted my filament above the printer and used ptfe tube to guide the filament to the ectruders in their original position.

Regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 07/03/2018 7:25 pm
kursat.u
(@kursat-u)
Eminent Member
Re: Shortening PTFE tubing

You can set the Bowden tube length even individually via factory reset.
I've done it myself, for a tube which was little longer due to assembly problems
I've also kind of tried to do what you have done. It bends way to much a higher z's.
I've tried to move the extruders together with x assembly but did not have time to complete it.

https://help.prusa3d.com/l/en/article/SYvbQ66IXF-factory-reset

Posted : 09/03/2018 8:58 am
mavu
 mavu
(@mavu)
Estimable Member
Re: Shortening PTFE tubing

Yes, won't work, BUT if I remember correctly, you can set the lengths in the system menu, which you can reach by holding some button while powering on.

Still would not recommend it. The MMU is not the most robust printing device at the best of times, and changing things that way is asking for trouble.

Posted : 09/03/2018 9:00 am
patrick.c3
(@patrick-c3)
New Member
Topic starter answered:
Re: Shortening PTFE tubing

Thanks for all your replys! If figured it would cause issues. The truth is I the length of the tubing was the least of my problems. It all happened in the multiplexer. I printed the redesign I found on thingivese and haven't had an issue yet. But It still wasn't performing like the MK2s so I switched back to single color. I see that they are working on a redesign for the MMU. I'll just wait until that's done. I don't do that many multicolor prints anyway and I was spending more time fiddling around trying to get a good print than actually printing stuff. Once I switched back it was back to normal:) Just finished a 38hr print without any issues. Good things come to those who wait 😀 🙂

Posted : 19/03/2018 8:03 pm
Share: