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[Closed] Problem with Printing after MMU install  

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ten13th
(@ten13th)
Active Member
Problem with Printing after MMU install

I am at a lost on what is causing my printing issue.  This issue started approximately after I installed the MMU.  I'm on the latest MK3S/2.5S and MMU firmware.  The best way to describe the problem is the printer would act as it is not getting enough material so it would air print or underprint a section.  First layer would be fine for the most part, with some spots that is underprint.  The problem really shows up on the fill layers.  I have slow down the speed to 70% but without improvement.  I have even installed a brand new hotend to make sure there is no blockage in the hotend.  I have also tightened the tension on the filament gear, should I tighten it more?  I see the same problem with PETG and PLA.  Any thoughts on what might be the cause of this problem?  And remedy for it?

 

This topic was modified 4 years ago by ten13th
Posted : 21/10/2019 11:04 pm
CCryder
(@ccryder)
Active Member
RE: Problem with Printing after MMU install

After doing an MMU install (and also building a dry box), I had similar issues.  They were caused by too much friction in the filament path.  Do an extract filament (front panel command) which will push the filament out the front of the MMU.  Pull on it to see how much force is required.  I'm still working on a satisfactory solution, but it involves going to the 6 mm PTFE tubing in all the filament paths.  When I'm satisfied, I'll put it up on Thingiverse.

Posted : 17/11/2019 3:17 am
ten13th liked
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Problem with Printing after MMU install

Hi Carroll, 

 

I use 2.5 X 4 PTFE for all tubes except the one in the extruder cold end

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 : 17/11/2019 9:26 am
CCryder liked
CCryder
(@ccryder)
Active Member
RE: Problem with Printing after MMU install

Hi Joan--

Thank you!  I did not know that this was available.

Regards,

Carroll

 

Posted : 17/11/2019 7:11 pm
rmm200
(@rmm200)
Noble Member
RE: Problem with Printing after MMU install

Bulk PTFE is readily available. Buy from a reputable 3D Printer supplier. Double check the bore is centered - and big enough.

Cutting jigs are available on Thingiverse, and Prusa has published detailed charts on cutting and tapering.

Posted : 17/11/2019 9:45 pm
CCryder liked
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Problem with Printing after MMU install

@joantabb

Exactly these PTFE tubes I use and they reduce the friction caused by the filament transport considerably, but it's not so easy to find a shop (germany, austria).

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 17/11/2019 10:06 pm
CCryder liked
CCryder
(@ccryder)
Active Member
RE: Problem with Printing after MMU install

Thanks, everyone, your comments are very helpful.  There's certainly plenty of cutting jigs to pick from on Thingiverse!

Posted : 18/11/2019 5:09 am
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