Extruder clogging with MMU2S
Anyone else seeing higher than normal extruder clogging? Prior to the MMU2S I never had issues with clogging. Now with the MMU2S on the upgraded i3 MK3S it's happening way too often typically associated with MMU failed to load. I completed a print (working on the retractable spool holders in single extruder mode) and now starting a new print and the filament won't load into the extruder. MMU is fine. I have to heat up the hot end, use the rod to push the filament out and then remove and cut the angle on the filament and all is fine again.
Anyone else having this problem or have suggestions on how to improve the reliability?
Neal C
Richmond, VA
RE: Extruder clogging with MMU2S
I am having similar issues. After I've disassembled the extruder, I've noticed a few pieces of filament that slipped between the PTFE tube and the extruder body. This was clogging the whole extruder. Another thing is, during the assembly of the MK3 -> MK3S, I did not get the bowden gear attached to extruder motor aligned properly with the center of PTFE tube. After I've fixed those 2 issues, the MMU2 is working as a charm, so far 50h++ prints without a single failure!
RE: Extruder clogging with MMU2S
I dont know if this is specific for me, but whenever i use a MMU profile (e.g. Prusament PLA MMU2), the cooling fan is set to full speed by sending a "M106 S255" to the printer.
This happens, independently of what i select as minimum (min_fan_speed) and maximum (max_fan_speed) cooling speeds for the fan. So max_fan_speed 20% => Still full speed. I guess this is intentional, but i cant figure out why.
Now, i had severe problems with clogging too. and i just finished a 2h print without clogging by changing that single "M106 S255" to a "M106 S100".
Does anyone experience this too? Or is there a reason why with the mmu the fan should always stay at full speed?
I also have a live chat currently open, but no one is answering me sadly.
- edit:
Just to have mentioned it, this happens with SlicerPE-1.41, 1.42 and 2.0.0 all rcs.
RE: Extruder clogging with MMU2S
Can you share your project 3MF file or gcode? 100% fan speed is used by default for PLA filament (not only for MMU). It is part cooling fan speed, so it shouldn't be related to clogging (as long as hotend temperature is stable). I tried to change min and max fan speed in cooling settings and it works as it should.
RE: Extruder clogging with MMU2S
I did have to adjust the "chimney" and I also had to adjust the hotend in the assembly for those issues.
I have a Prusa,therefore I research.
RE: Extruder clogging with MMU2S
Hello,
i did save a m3f file with the problematic print, i was however unable to attach it to this post. Here is a screenshot of the model:
The goal of the model was to have an extended LACK foot piece to be able to mount the MMU2s into my lack 3d printer table. The designers skills are discussable, however this is the model we are talking about :P.
It seems like the problem is a mix of min_fan_speed / max_fan_speed being set to 100% too early and the default setting for the fan says to start with full power at layer 1. I guess the print speed is not adjusted because the "font model" that is printed to the model is really small on every layer.
Here is a screenshot of the default settings:
If this is the default, then my hotend is definitly getting cooled down too much... i checked all parts of the setup several times, but i dont think it sits too high or anything:
Any advice is welcome. If i set the start cooling layer to 3 or something bigger, the prints usually run through well though.