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Initial Problems with MMU Test and Print  

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Dewey79
(@dewey79)
Honorable Member
Initial Problems with MMU Test and Print

Having initial concerns and problems with my MMU v2 on a MK3.

The build went great and was straight forward, if you can build the printer you can build the MMU. Plugging in the electronics wasn't an issue either. The first thing I did was to upgrade the firmware on both the printer and MMU. This completed also with no errors.

My issues started when I attempted to load filament. The first issue before I can do anything else is to reinstall the cutting blade. When attempting to load filiament I hit the wrong button and I think the filament was advancing while trying to cut it.
The main issue I'm having is with the amount of drag or tension coming from the filament spools. I'm lerry about the tension putting a strain on the drive motor. Maybe this is why people are seeing them heating up and one where the MMU drum is melting.

How are is everyone else dealing with this?

Publié : 19/11/2018 5:45 pm
JuanCholo
(@juancholo)
Honorable Member
Re: Initial Problems with MMU Test and Print

you want to change the spools to this design
https://www.thingiverse.com/thing:3113520

uses the same parts prusa gives you you just need an additional 1" PVC pipe or you could 3d print the tubes but it will take a very long time.
the tubes are 85mm long and you need 10 of them.

when i changed mine out on day 1

also use a 2mm drill bit to clean out the L brackets/back stops that the filament goes into from the spools. this will reduce the friction more getting into the TPFE tubes. and watch to make sure you didn't turn the bolts that hold the tubes too much. 1-2 threads into the PETG is all it needs. kissing the tube so there is no pinch in the tubes.

i would also recommend using some
seperators
https://www.thingiverse.com/thing:3166394

the tubes are long and they move around and they can disturb the filaments. which may accidentally roll out one from the tube and hit the selector or knife and cause a jam on load/unload.

also i recommend positioning the spool in a 1/4 circle if possible, but either way once you place a spool holder Tape it down to the table so it does not move by accident.

“One does not simply use a picture as signature on Prusa forums”

Publié : 19/11/2018 5:57 pm
Dewey79
(@dewey79)
Honorable Member
Topic starter answered:
Re: Initial Problems with MMU Test and Print


you want to change the spools to this design
https://www.thingiverse.com/thing:3113520

uses the same parts prusa gives you you just need an additional 1" PVC pipe or you could 3d print the tubes but it will take a very long time.
the tubes are 85mm long and you need 10 of them.

when i changed mine out on day 1

also use a 2mm drill bit to clean out the L brackets/back stops that the filament goes into from the spools. this will reduce the friction more getting into the TPFE tubes. and watch to make sure you didn't turn the bolts that hold the tubes too much. 1-2 threads into the PETG is all it needs. kissing the tube so there is no pinch in the tubes.

i would also recommend using some
seperators
https://www.thingiverse.com/thing:3166394

the tubes are long and they move around and they can disturb the filaments. which may accidentally roll out one from the tube and hit the selector or knife and cause a jam on load/unload.

also i recommend positioning the spool in a 1/4 circle if possible, but either way once you place a spool holder Tape it down to the table so it does not move by accident.

Daniel,
Thank you for your reply. I've seen this update and was going to try it, but ran out of weekend. In addition to the holders I'm feeling some tension from the tubes themselves. I was thinking of going to "Capricorn Bowden Tubes and quick fittings", but those tolerancesare tighter than the provided tubing.
The 1" pvc sounds like a quick solution so I'll pick some of that up on the way home.

Publié : 19/11/2018 8:24 pm
JuanCholo
(@juancholo)
Honorable Member
Re: Initial Problems with MMU Test and Print

my tubes appear to have worked themselves in after a little time. i wouldn't go tighter on the tolerances because the ramming shapes the tip a little and it just makes it with the looser tolerance. tighter might jam the tips after shapeing.

“One does not simply use a picture as signature on Prusa forums”

Publié : 19/11/2018 9:05 pm
Dewey79
(@dewey79)
Honorable Member
Topic starter answered:
Re: Initial Problems with MMU Test and Print

The newest problem is the blade keeps popping out of the selector when I try to even attempt to load filament.

I saw a modification from this thread below, but does anyone have any other ideas before I modify the MMU?

https://www.thingiverse.com/thing:3157550

The blade holder has 3d printed pins that helps to keep the blade in the correct orientation when locked in place.

Publié : 01/12/2018 5:40 pm
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