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XinKaiSen
(@xinkaisen)
Member
Single Color Print Fails

Hey all-

I've recently (finally) gotten my MMU3 built and installed and it's pretty awesome, and I got the sheep test object to print after a bit of tweaking.  However, now my single color prints tend to fail when using the MMU3.  An early single color print yielded a large blob at the start of the priming strip:

After a few cold pulls that all came out clean, I started to print the object and it failed about 2/3 of the way up.  (The intended object was basically a taller version of what's visible.)

At the end of the print the orange filament retracted back into the MMU and I did a few more cold pulls (red filament) just to check.  There was a good amount of orange filament that still came out before the red started going through.

Any ideas as to what the problem might be?  I eventually got the object printed by removing the tube connecting the MMU and the extruder and just directly inserting the filament.  Is this the best option for single-filament printing?

Posted : 10/08/2025 1:47 am
rex555
(@rex555)
Eminent Member
RE: Single Color Print Fails

Could be a lot of things, removing the tube is a weird solution but a couple questions:

  • How long are your PTFE runs from spool to buffer and buffer to MMU, and how tight are the turns? removing a tube could be reducing friction by just enough to feed better
  • Have you tried with different filament and is your filament dry?
  • Are you sure your filament settings in slicer are correct temps for your chosen filament?

Those are the first things I would check

 

Posted : 13/08/2025 7:50 pm
XinKaiSen
(@xinkaisen)
Member
Topic starter answered:
RE: Single Color Print Fails

I was using the full-length PTFE tubes and all the default hardware in the standard configuration. I removed the PTFE tubes and bypassed the buffer and that seemed to fix it. Thanks for the suggestion!

Posted : 26/08/2025 9:39 pm
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