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Joined: May 29, 2018 6:38 pm
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MMU2 stops feeding filament

Dec 01, 2018 9:53 pm

TLDR: MMU2 stops extruding filament once print has started.

To explain what was happening:

I had just finished a 6hr print that was using the MMU2's single mode where I select the filament for it to print with.

Everything seemed fine. I then went to start another print using the same color. The MMU2 loaded the filament like I would expect but all of a sudden it move the nozzle over, unloaded the filament and went to the next one (I have auto deplete on). I decided to stop the print and try it again.

After getting the filament loaded properly I started the print. The print would start fine but would start slipping on the hot end's extruder gear as if there was a jam. I tried some different settings unloading and loading the filament and eventually went to see if it was heat creep. After cleaning everything out I ran filament through it and it seemed fine.

Started the print again the MMU2 loaded the filament as expected, but at some point is started skipping again.

I happened to look at the MMU2 and saw that it wasnt even moving so it was holding the filament in place while the extruder was trying to do all it could to pull it through.

I eventually unhooked the MMU2 bowden tube ran some filament through it and had it think it was loading the filament took another spool and directly put it into the extruder.

I can confirm the MMU2 is not moving at all and the printer prints fine with a direct feed.

I don't know what caused this and why it is doing this, but is this something that has been reported? Now I don't even want to use it, if it may stop moving the gears again.

Keep in mind I have tried a few prints including one I know worked before the issue arose.

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Joined: Dec 04, 2017 1:26 pm
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Re: MMU2 stops feeding filament

Dec 09, 2018 7:45 pm

I have had something similar.

I was midway through a print and it started to under-extrude. On investigation it was exactly the same thing. The MMU2 had stopped so the Mk3 extruder was trying to pull a locked filament.

On further investigation I found that the MMU2 had disappeared from the Mk3 -ie the Mk3 had reverted back to the original software, so the filament load / unload options were the normal core Mk3 ones.

So in my case this issue was caused by a software disconnection with the MMU2.

Anyone else expeience this type of thing?

Posts: 108
Joined: Sep 25, 2017 6:22 am
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Re: MMU2 stops feeding filament

Dec 13, 2018 9:01 am

Seems to occur randomly, so it is difficult to find out the cause.
Either the MMU motors are powered off by itself or the loading/selecting sequence is wrong.

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Joined: Aug 17, 2018 7:51 pm
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Re: MMU2 stops feeding filament

Dec 30, 2018 9:42 am


I have the same problem. The Pulley motor on the MMU2 doesn't rotate => only the motor on the extruder run => nothing go out because is too hard for him to take the filament.

Is not a problem with the motor or connection because this motor work fine for the loading and unloading of the filament.
I also have sometime the menu that come back to the MK3 menu but is not link with the problem.
I already print correctly some objet with the MMU2 => but with the old version of the firmware => I suspect the last release.

Have a nice day


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