New MMU2, utterly confused and frustrated...
Ok, spent the weekend building the MMU2. Did the extuder cooling upgrade on the Mk3 (which was running PERFECTLY since June)...
I'm at my wits end trying to understand this MMU though...
Double checked all wiring, construction, etc.
1) the cutter blade keeps snagging as the changer head moves, one time turning it into a projectile as it flung itself across the room (NOT COOL!!!) I'm utterly confused how this is EVER supposed to stay in place. I've decided to go without for now.
2) I FINALLY managed to do the tube length calibration and gotten the filament #1 to load properly down to the extruder and did the First Layer calibration. I say successfully, but there seems to be so much friction + weight from the spool that there were some small breaks in the line laid down (like there wasn't enough filament flowing in). HOWEVER, it doesn't seem to be retracting enough at the end. I say that because...
3) trying to change to filament #2 to repeat the First Layer Calibration, the selector jams because there's still some filament left in the tube from 1 past the FINDA (shouldn't it be retracting until the FINDA no longer detects filament and then slightly more??? WTF good is the FINDA otherwise???) And when you "Load" the filament, shouldn't it go all the way down to the extruder??? It NEVER does that for me.
4) After manually cutting the filament #1 and resetting everything so it isn't into the selector, I go in and try to do a second First layer calibration selecting Filament #2. The selector moves, and then suddenly filament #1 starts streaming out of the side of the selector and NOTHING is happening with #2!!! ARGH!!!!
So far this thing is beyond a POS IMO... How the heck did it get out of beta test like this??!? I almost feel like the Idlers bearing rotary selector thing isn't working right...Like it's going backwards or something.
This is all with the 1.0.1 firmware on the MMU2 and 3.4.1 on the printer. Latest 2.2.0 drivers package.
ideas??? Because right now I'm tempted to unplug the damn MMU2 from the printer and just go back to single color for the time being...
Re: New MMU2, utterly confused and frustrated...
Hi,
My MMU2 works quite well so far, I understand your frustration but I think you can have it to work with few things.
1) Never had problems with the blade but you're not the only one, mine have never been usefull but if you need it and it's not there, don't know if it would damage something.
2) Agree that there is a lot of friction in the filament brake system that brings underextrusion for me, I totally removed it but unlike a lot of people I have a lot of place so I put my spools far from the printer and separate filament with box, works really great. If you don't have so much place there are alternative mounting and more coming soon.
https://shop.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles--f57/mmuv2-first-impresisons-and-lackrack-setup-t24877.html
3) - Yes filament retractation should pass the FINDA and be removed from the selector, didn't you notice an error message from the MMU LED at the end of your first layer calibration ? On first prints you have to be really carefull of this and not trust it works well
- No when you load filament it doesn't reach the extruder, it's load until the FINDA detects it and then unload from the selector. It makes your filament ready for use (what would happened if you select load all filament ?).
4) I saw someone talking about this synchronization problem somewhere, have you tried resetting the MMU2 unit and the MK3 cards ?
Good luck !
Re: New MMU2, utterly confused and frustrated...
3) trying to change to filament #2 to repeat the First Layer Calibration, the selector jams because there's still some filament left in the tube from 1 past the FINDA (shouldn't it be retracting until the FINDA no longer detects filament and then slightly more??? WTF good is the FINDA otherwise???) And when you "Load" the filament, shouldn't it go all the way down to the extruder??? It NEVER does that for me.
When it retracts the filament, it will attempt to pull it past the FINDA, completely out of the selector, but stop while the filament is still in position to be grabbed by the drive gear next time it tries to reload.
If this is not occurring, several possible debug avenues:
Re: New MMU2, utterly confused and frustrated...
I had a problem where the idler assembly was becoming loose on the shaft allowing the idler bearings to either be too loose on the chosen filament, or tightened on the complete wrong filament. I think the root cause of mine was the idler actually softening up ever so slightly from the heat of the stepper (my MMU2 is all black so it sucks up a little more heat than the orange I'm assuming). I reprinted mine in polycarbonate and have not had any more problems with it. This may be something to check. Try to wiggle it on the shaft while it is on and warmed up.
Cheers,
Brian