Filament not retracting fully - causing jamming
Background: MK3S with MMU2S - worked pretty well, with a couple issues mostly due to the underpowering of the motors. Upgraded to MK4 and MMU3.
The MK4 portion works great. However I have had a lot of issues with the MMU with the filament getting jammed at the Selector. From what I can see it appears that the filament, when retracted, doesn't always fully retract so when the Selector moves its bends the filament tip. Then on the next load of that filament it can't feed into the Selector. Sometimes it doesn't retract a fair amount so it drags the filament out and then jams under the selector.
It doesn't happen on every change and I can go thru a couple dozen or so changes before it happens. In addition its not always the same filament/position that does it. I've tried
- turning on "cutting" the tip, but that didn't help.
- loosening and tightening the screws on the ideler cover, but that didn't help
Thoughts/suggestions on what could be causing it or what to try next?
- 1st "printer" TIKO 3D
- 2nd PRUSA i3 MK2S with MMU v1
- 3rd PRUSA i3 MK2S
- 4th PRUSA i3 MK3 with MMU v2- 5th PRUSA i3 MK4 (upgraded from MK3) with MMU v3 (upgraded from…
RE: Filament not retracting fully - causing jamming
It has started doing this to me the last 7 days or so as well.It never happened before and I have tried all the above points and the condition is the same.
I own: MK4 and MMU3
RE: Filament not retracting fully - causing jamming
I’m having the same issues with mk4/mmu3. I get it to preload and load to nozzle functions but when I start my print, it starts. It is not always the same slot and not all the time. I have changed filament to new filament but still same problem. Could it be the cutter on the selector?
RE: Filament not retracting fully - causing jamming
Same problem with my MK4/MMU3 setup. Seems as if the filament isn't loading into the MMU correctly no matter what I try. It was suggested to Recalibrate Filament Sensor, Clean Finda Sensor and/or Hard Factory reset. When using the MK4 alone, all is fine and works perfectly. Frustration....
RE: Filament not retracting fully - causing jamming
Following up to this issue. It seemed that my MMU board was at end of life. It happens. Replaced the board, ran a few calibrations and everything seemed to go back to normal.
RE: Filament not retracting fully - causing jamming
Which board are you referring to?
--> MK4 - MK4S - MINI+ - MMU3 - Accelerometer Guide - BambuLab A1 Combo <--
RE: Filament not retracting fully - causing jamming
Specifically, the MMU Control board in the MMU unit was replaced.
RE: Filament not retracting fully - causing jamming
Strange that the electronic board was 'end of life'?
I've not come across this with electronic components before.....
Glad its resolved, but doesn't fill me with confidence considering Ive just taken delivery of a MMU3!
--> MK4 - MK4S - MINI+ - MMU3 - Accelerometer Guide - BambuLab A1 Combo <--
RE: Filament not retracting fully - causing jamming
My mistake. I should have checked the connections and found that the small connection had dislodged slightly. Once I pushed connector in the mmu started working correctly.
RE: Filament not retracting fully - causing jamming
I forgot that I never updated my experience on this - Sorry.
So, I was having the issue I original posted about. Then a few weeks later my main board on the MK4 died. When the printer booted up it would blue screen with a TMC driver fault. I talked with Prusa Support and they sent me a new main board. Replaced it, went thru all the startup calibrations, and started printing single filament without issue. Decided to try and print a MMU print and everything worked great. After printing about 6 different MMU prints I had 1 minor jam, similar to my original post, but easily fixed and the print completed.
One thing that I do different now is that I load all 5 filaments to the MMU even if I'm not using all 5 in the print.
- 1st "printer" TIKO 3D
- 2nd PRUSA i3 MK2S with MMU v1
- 3rd PRUSA i3 MK2S
- 4th PRUSA i3 MK3 with MMU v2- 5th PRUSA i3 MK4 (upgraded from MK3) with MMU v3 (upgraded from…