MK4 + MMU3 not unloading filament after print
 
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NusNus
(@nusnus)
Member
MK4 + MMU3 not unloading filament after print

Hi all,

My previous printer was a MK3S with MMU2S. Every time a print was finished (sliced either as MMU or single) the filament was unloaded from extruder automatically and printer was ready to go.
Now with MK4 and MMU3, after print in single mode is finished, the extruder cools down and screen is asking what material I have loaded so that it can unload it. This is a very unnecessary step as the printer has just printed with the correct temperature and should just unload the filament.

Is there a fix for this? I do not want to slice as MMU because then I cannot choose filament in the beginning of each print.

Posted : 28/06/2024 7:15 am
2 people liked
kassi
(@kassi)
Active Member
RE: MK4 + MMU3 not unloading filament after print

Same issue here, even though I loaded the filaments using the advanced menu item where I tell the printer which material is in which slot.

The positive side effect of this is, that I also have the option to not unload by simply choosing "back" and start the next print with the same material right away.

The annoying thing however is, that the print and state of the printer never really finishes (as in PrusaLink) but stays "busy" somehow.

I wonder if there's a gcode where I could tell "do not unload and simply finish print" or "unload" - and printer should know with which temperature to do that.

Posted : 04/07/2024 10:20 am
Kujiwawa
(@kujiwawa)
Member
RE: MK4 + MMU3 not unloading filament after print

I am having the same issue with the filament not retracting back to the MMU3. When I first installed the MM3 the retraction was happening. Was this a change in the firmware? Currently using 6.1.3

After every print I have to keep hitting ok for the filament to retract 10-20 mm at a time until it is parking passed the MMU sensor. Does someone know if this could be a change in the gcode?

Posted : 11/10/2024 6:13 am
Brian Amato
(@brian-amato)
Active Member
RE: MK4 + MMU3 not unloading filament after print

This just started happening to me as well.  I've been running the MMU3 and MK4 just fine for a while (even did the S upgrade).  At random it just started asking which type of filament to unload.  Was hoping firmware would correct it, but I upgraded to the beta and it's still asking me to unload after single prints.  Mostly an annoyance.

Posted : 30/10/2024 1:45 am
NusNus
(@nusnus)
Member
Topic starter answered:
RE: MK4 + MMU3 not unloading filament after print

I believe this is because you are slicing with a non-multicolor profile. Mine havent asked this question since i started to use a mk4+mmu3 profile.

So even if file is single color, i can choose in slicer which filament i want to use. This has the advantage that i can start prints from prusa connect because the filament is already specified.

Posted : 30/10/2024 8:05 am
3D printer
(@3d-printer-2)
Member
RE: MK4 + MMU3 not unloading filament after print

The bug is still there and not fixed. Very annoying...

Posted : 06/06/2025 8:57 pm
Walter Layher
(@walter-layher)
Noble Member
RE: MK4 + MMU3 not unloading filament after print

Did you select the correct filament type in the display under Filaments > Load to MMU Extended (or very similar name, I won't turn on the printer for this)? There you select the filament number and when you click the wheel you can select "Don't change" or you can select the filament type that should be loaded. When I do this the filament gets unloaded after the print job when I print with a single filament via the MMU3.

Posted : 06/06/2025 10:06 pm
3D printer
(@3d-printer-2)
Member
RE: MK4 + MMU3 not unloading filament after print

Yes, I have selected the correct filament type in the MMU filament settings. But with my self adapted PETG filament profile I print with different temperatures than the filament temperature presets in the printers firmware. Not sure if this is why at the end of the print the printer asks me which filament is inserted before heating up to the specific temperature to unload it. But it still makes no sense as the printer knows the last filament type that has been printed.

I will try to fix it via a custom gcode and will let you know if it works then.

Posted : 07/06/2025 6:50 am
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