Notifications
Clear all

MMU2s still engaged in single color print mode  

  RSS
Nikolai
(@nikolai)
Noble Member
MMU2s still engaged in single color print mode

Hello,

I'm printing with single color on the MK3s/MMU2s and was surprised to see some interesting behavior.

During the print the MMU2s doesn't release the filament. It looks like the MMU2s extruder motor is deactivated so the MK3s extruder motor is pulling the filament. But it has much higher resistance because it also need to pull the MMU2s rollers and the MMU2s extruder motor.

I remember we had a slightly similar discussion already previously but don't remember the outcome. Does anybody has more insight knowledge why it still grabs the filament at the MMU2s? My expectation would be (and I remember it was previously the case) that revolver is releasing the filament once loaded.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 09/07/2019 5:11 pm
Dave Avery
(@dave-avery)
Honorable Member
RE: MMU2s still engaged in single color print mode

IR sensor or FINDA is probably intermittent . the reset button on the MMU ( next to the micro USB port)  should reset it to pass-thru mode

Posted : 09/07/2019 5:21 pm
Nikolai
(@nikolai)
Noble Member
Topic starter answered:
RE: MMU2s still engaged in single color print mode
Posted by: david.a66

IR sensor or FINDA is probably intermittent . the reset button on the MMU ( next to the micro USB port)  should reset it to pass-thru mode

Might be (in millisecond range, so it's not visible on the screen) but in this case it would have issues in loading/unloading process. But it looks like it's a correct behavior. It loads, disengages the MMU2s extruder motor, so it's not grinding or something and keeps printing with the roll/revolver still in the same position. 

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 09/07/2019 5:27 pm
toaf
 toaf
(@toaf)
Noble Member
RE: MMU2s still engaged in single color print mode

I just had the same thing happen last week, i ended up flashing the mk3s firmware to an older version then going back. it's crazy isn't it?

I have a Prusa,therefore I research.

Posted : 09/07/2019 5:50 pm
Nikolai
(@nikolai)
Noble Member
Topic starter answered:
RE: MMU2s still engaged in single color print mode

I mean it's printing fine, so I don't see a reason to downgrade. But wandering if it's a bug or a new feature to detect filament is still moving. Or if it serves any other purpose.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 09/07/2019 5:56 pm
toaf
 toaf
(@toaf)
Noble Member
RE: MMU2s still engaged in single color print mode

I think its possible the firmware isn't stable, mine was bad enough it was unusable. even in mmu mode.

I have a Prusa,therefore I research.

Posted : 09/07/2019 6:00 pm
Nikolai
(@nikolai)
Noble Member
Topic starter answered:
RE: MMU2s still engaged in single color print mode

Looks like we are not alone: https://github.com/prusa3d/Prusa-Firmware/issues/1946

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 09/07/2019 6:07 pm
toaf
 toaf
(@toaf)
Noble Member
RE: MMU2s still engaged in single color print mode

ouch, I know it was going on all filament paths for mine.  troubleshooting it was the biggest part of figuring out what was going on.

I have a Prusa,therefore I research.

Posted : 09/07/2019 6:11 pm
TickTock
(@ticktock)
Estimable Member
RE: MMU2s still engaged in single color print mode

Yup.  I reported the same thing during a multi-color print.

https://forum.prusa3d.com/forum/original-prusa-i3-mmu2s-mmu2-assembly-and-first-prints-troubleshooting/mmu2-sometime-doesnt-release-filament-video/

Posted : 10/07/2019 12:28 am
Share: