Just so many problems...
I wont discount its just me but in 24 hrs here are the list of my problems. I honestly don't see how anyone would not have to watch the entire project print.
1. When you're low on filament spools are pulled right out of the trays...spool holders are just crap.
2. Calibration took multiple attempts per filament never really matching what i set it to...but i got close and went for it.
3. Filaments not retracting properly 100% regardless of how I tighten down the assembly maybe it would switch a few times correctly and then not.
3b. because of bad filament retraction...I had... the selector not move over....or it would move over crushing the previous filament then failing to load the next filament. I even had the machine fail to move the selector over but attempted to load the next filament shooting 5 inches of it up in the air.
The most ive gotten was half way through a lizard before I had so many clogging issues i gave up for the night.
So many what ifs how can this thing be trusted to finish a print alone.
FYI Im using the MK3...newest firmware.
I am just going to start over with everything but really has anyone been able to just leave it for say a 5 hr print and have it finish? I just dont know how/where this tings sweet spot is.
Re: Just so many problems...
I've had a long print succeed (12+ hours) but several times the filament changing failed so the print paused until I got the MMU2 straightened out, so you have to keep an eye on the print. This guide https://manual.prusa3d.com/Guide/MMU2+filament+jam/779?lang=en helped a lot - the LEDs and lights are not obvious, but this manual helped me recover from mis-loads.
I agree that the MMU2 is much tricker than regular printing. 3D printing isn't "plug and play" at the best of times, and while the Mk3 is arguably the most consistent 3D printer, unloading and loading every filament color for every level means hundreds of filament unload/reloads, so even a 99% success rate for each filament swap means that failure is common. But so far failed filament swaps are usually detected so I can clip off the damaged filament (usually a chunk worn into the filament by the MMU2 gear) and reload the filament and continue the print. As far as I can tell, the failures are either the filament going not quite far enough into the extruder so the gear doesn't grab the filament, or it goes too far and the MMU2 gear chews a dent into the filament trying to push through the extruder's stopped gear.
I'm hopeful that they can figure out how to get the filament detector above the extruder to work reliably, at least for telling when new filament enters the extruder, and run both motors at the same time at the same speed, at which point I think the MMU2 will become more reliable, because loading won't require calibration of distance (and guessing), it'll just load until the filament enters the extruder, when it can just run both motors for a second (IMO) and the filament will be loaded every time.
Re: Just so many problems...
Check out my filament wallet. It will really help - a few others are making prettier versions.
I maintain an informal list of San Diego, CA 3D printing enthusiasts. PM me for details. If you include a contact email and I can add you to the informal mailing list.
Re: Just so many problems...
So I got a success last night. 8 hrs and 2 mins long and I had one bad unload.
My changes..
1. Redid calibration one more time for all five filaments
2. cut the tubes down to maybe 5 inches.
3. took the black 3d printed parts attached to the spool holders and just tossed them in a box.
4. Made a few changes for the filament and printer in slicer.
The slicer changes came from this video, so thank you to 0Calvin if hes on the forums.
So with these few changes my machine went from bad loads/unloads maybe every three changes to 1 bad unload in 8 hrs and it was only the black that failed the green and gold of the body was perfect all night.