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MMU2S - No prints, only problems.  

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fcampanini
(@fcampanini)
Active Member
MMU2S - No prints, only problems.

Hello everyone, i kind of understand reading here that this will be just a shot in the dark but...

After the assembly of the MMUS2 few days ago I'm still not able to print anything, not even the first layer calibration.

After some struggle first in understanding and then in making the calibration of IR, i did manage and now if i check under support ->sensor info i see everything behaving correctly, both IR and FINDA.

However I can load the filament in the tube 1 of the MMU, the filament is correctly loaded, retracted and the light gets green.

I then select to load the nozzle and nothing happen. The printer finally  behave like the filament was loaded and ask me if the color of the extrusion is correct. Obviously nothing is extruded cause there is no filament in the extruder.

That's it.

Can anyone help me?

Thanks,

Filo

Posted : 19/06/2019 8:18 pm
Spyryt
(@spyryt)
Active Member
RE: MMU2S - No prints, only problems.

Did you check you IR sensor value after this? It shouldn’t start attempting to extrude if your IR is at zero.if it showing 1 with no filament, go ahead and re-calibrate.

Posted : 19/06/2019 11:33 pm
Heywood J'blowme
(@heywood-jblowme)
Active Member
RE: MMU2S - No prints, only problems.

I know you check the IR sensor in "statistics", but how can you check this when it asks if filament is loaded?

 

I hit no, nothing happens and it asks me again.

 

I wiggle the tower door to see if it is giving false reading, but no change.

I was actually having problems doing a proper first layer with filament 1 (black) (very stringy) so I tried to get other colors to load and they will not.

I was thinking the idler could be too tight or too lose, but cant find the proper setting.

Very frustrating that I cant even get back to good single color prints like I had with the MK3 before the S and MMU upgrade.

 

Now

 

Posted : 20/06/2019 6:42 am
Spyryt
(@spyryt)
Active Member
RE: MMU2S - No prints, only problems.

When I ran into this problem, it was a combination of my IR sensor and my MMU tension screws being too tight.

First, only load up filament 1. Leave others empty. Then cycle MMU through all 5 and make sure the idler turns correctly. If it starts clicking, move it all the way back to position 1, then loosen the 2 screws a little. Then try again. Do this until you can go to position 5 with no clicking.

My tension screws are more loose than Prusa said they should be. It’s not an exact science.

Now move to position 2 and then try loading position 1 to nozzle. Watch the MMU and. Are sure it turns to position one and starts spinning.

pull up sensor info and check IR status.

Posted : 20/06/2019 10:46 am
Heywood J'blowme
(@heywood-jblowme)
Active Member
RE: MMU2S - No prints, only problems.

Thanks for the quick reply,

 

I backed off the screws significantly, they seem to have load to top better.

Screws are above flush by about a small coin, or wire tie thickness.

 

Pinda shows 1

IR 0

Finda 0

Go to load to nozzle, Door is either too lose or too tight, seems like the drive gear is just eating the filament rather than feeding it.

 

Dumb question, but do I need to re-slice all my projects after converting from MK3 to MK3s MMU?

 

Cant seem to get the calibration 75X75  test file to print it freezes in one corner, and I have to shut down.

 

 

 

 

 

 

Posted : 20/06/2019 12:39 pm
gnat
 gnat
(@gnat)
Noble Member
RE: MMU2S - No prints, only problems.
Posted by: doug.m11

Dumb question, but do I need to re-slice all my projects after converting from MK3 to MK3s MMU?

Not a dumb question in my book as I would expect the printer to be smart enough to recognize that the MMU is attached and treat it like a MMU Single print. It is not that smart however and will not print correctly.

In my case it reboots the printer after doing the bed leveling. Another report I saw it was get through the bed leveling and then just extrude a blob.

MMU tips and troubleshooting
Posted : 20/06/2019 2:16 pm
Heywood J'blowme
(@heywood-jblowme)
Active Member
RE: MMU2S - No prints, only problems.
Posted by: gnat
Posted by: doug.m11

Dumb question, but do I need to re-slice all my projects after converting from MK3 to MK3s MMU?

Not a dumb question in my book as I would expect the printer to be smart enough to recognize that the MMU is attached and treat it like a MMU Single print. It is not that smart however and will not print correctly.

In my case it reboots the printer after doing the bed leveling. Another report I saw it was get through the bed leveling and then just extrude a blob.

Yes, that what seems to happen on my attempts as well, when it was at least feeding properly.

 

Seems very temperamental. sometimes it will do the leveling, and then retract the filament.

 

Posted : 20/06/2019 3:52 pm
Lichtjaeger
(@lichtjaeger)
Noble Member
RE: MMU2S - No prints, only problems.
Posted by: doug.m11

Dumb question, but do I need to re-slice all my projects after converting from MK3 to MK3s MMU?

You need an other load procedure. For MK3S MMU Single gcode you load your filaments and choose which of them after selecting the file. For MK3(S) files you first need to load the filament to the nozzle and then select the file.

Posted : 20/06/2019 3:52 pm
fcampanini
(@fcampanini)
Active Member
Topic starter answered:
RE: MMU2S - No prints, only problems.

Update on this disaster.

After several attempts to correctly set the IR in terms of calibration, I finally managed to have a first layer and a first print done with one single filament. Frankly the quality of the print does not seem to me the same as before (before the update when I had with MK3 extruder) but it's correct in terms of layers and shapes.... and maybe i'm just too negative due to this horrible user experience.

I started then with double color awk print and the world started crashing again...

I made a first test with 2nd and 3rd channels and the print failed because the filament didn't stick to the bed. It has never happened but... i cleaned with isopropil alchool and restarted.

At this point again the filament was not charged again into the extruder. Again IR sensor false positive. Again calibration. Done this I stacked again cause the FINDA was giving false positive. Moved the sensor and restarted the printer and the issues seems solved. I restarted again but at this point the filament on the channel 2 was not loading anymore. After some test (calibrate-ricalibrate) i discovered the filaments on 1 and 3 was working, so i changed the gcode and restarted. 3 failures with filaments underextruded, or quitting from the nozzol in an semisolid unutilizable way. Stop again. Changed the temparature, tried again but no way. Please consider that i'm using prusament PLA just to be safe. I guess i'm not correctly using the buffer so maybe the filament is not smoothly feeded.

I finished at 3 AM with no results at all:-(

I'll post next attemps but i'll probably give up and get back to old setup, even if at this moment i dont know how i will do it.

Filippo

Posted : 21/06/2019 10:03 am
Lichtjaeger
(@lichtjaeger)
Noble Member
RE: MMU2S - No prints, only problems.

Maybe you find someone on Prusaworld near you, who can offer you some technical support. I'm sure I could find the culprit and fix the issue if I had physical access to that printer.

Posted : 21/06/2019 10:09 am
fcampanini
(@fcampanini)
Active Member
Topic starter answered:
RE: MMU2S - Lots of problems but finally....

After some more testing and setup in particular on the buffer, I came finally in some decent result.

Now i can print in 2 colors with decent quality and no big problems.

Still remains:

1) first layer very difficult with some PLA spool... which BTW is prusament and I never had probs before the upgrade (the very same spool)

2)now I can say that the print quality is NOT at the level it was before

Some evolution:

PRINT FAILED

Print failed

PRINT COMPLETED BUD BAD QUALITY

Succeeded but....

BACK

BACK

PRINT OK

ok

BACK

BACK

I'll keep on testing

Filo

Posted : 21/06/2019 9:22 pm
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