I am frustrated with the MMU2S
Hi everyone,
i will tell you my story since i received and built my MMU2S at 15.02. this Year. I will not only Complain about what went wrong, but also offer my solutions which helped but keep in mind, i am writing this Letter as a Frustrated User which expected more quality from Prusa. The Mk3s+ Printer in was the heaven to work with but with the MMU2S it turned into hell.
Part 1 Assembly:
No complaints here. The Manual was awesome as i have expected from Prusa. Everything went fine, the Gummy Bears also contributed to my mood.
- Took me about 3 hours, which was fine and expected.
- i have directly installed the Rear PTFE holder to one from thingiverse https://www.thingiverse.com/thing:3657251
Part 2 First prints:
Now the first issues came in before i could even begin to print with multiple materials, all exchanges of the Filament failed right from the beginning. I have tried several things
- Changed the Rear PTFE holder back to the orginial one -> Didn't solve the issue
- Exchanged the standard Rear PTFE Tubes with wider ones (3mm inner diameter) -> Didn't solve the issue reliably
- Tried the Buffer in different orientations -> didn't solve the issue
- Changed the PTFE tube between the mmu2s and Printhead -> nope, no solution
At this point it took me about 20 hours (not joking) total and i was thinking i am going insane because of a project i wanted to do. Every single testrun took me about half an hour to an hour, and because i was trying to check if it's a fluke, i repeated those tests multiple times.
Next i tried the following:
- I disassembled the Printhead and exchanged every single thing because it was clogging the whole time, i was Suspecting Heatcreep or somewhing wrong with the hotend. -> Nope, another 10 hours to test every Possibility and now Money because i had to order everything.
- I have an enclosure running and thought the Heat would cause the unreliable exchange of the Filaments, so i bored 2 holes in my box and installed 140mm Fans. -> Nope again, 6 more hours wasted.
- finally, i was trying to pull the filament by hand at the print head end and found: it took too much pressure to pull it, even with 3mm Tubes. I pulled everything apart and found that the original Rear PTFE holder from the mmu2s was just a bit to snug so it pressed against the filament. -> that elimiated at least the clogging but the change of filaments was still unreliable.
- Now i got another issue, when the filament is being pulled back, the issue in my other thread happened ( https://forum.prusa3d.com/forum/original-prusa-i3-mmu2s-mmu2-hardware-firmware-and-software-help/filament-jam-when-unloading-its-not-the-common-ones-i-guess/) -> in a nutshell, there was still a pressure issue, but this time in the other direction (pulling). -> I have cut down every single PTFE Tube down to 5 cm at the mmu2s rear and that worked.
At this point, it was about mid March so 4 weeks since i received my MMU2S and was barely able to print with multi-materials. on the other hand, i could print with a single material just fine, except the pull back of the Filament at the end of each print failed.
I was now able to print my stuff since 2 weeks but it failed for several reasons, which was manageable but is still super annoying
One example: the MMu2s is displaying "i have an issue, please help": so i pulled back the filament, and did as any Guide is telling me to do, turned out, i was putting in the wrong filament because the mmu2s "forgot" which filament it was intentionally going to go. The Guides are telling "if every led is blinking: Press the reset button" .. i think you know what is happening now.
Proposal: Please display what the MMU2s was intending to do and failed at on the Display with the error-message of the Printer because the LED status are not really helping. It is like a customer calling and just telling "i have an issue" and nothing more.
And now the finale: last week the MMU2S just failed to load and unload the Filament again. I was using port 1 and 2 because using all 5 was still not reliable. I was opening the idler and it looked like the screws, which connected the idler with the shaft of the motor was loose, looks like i didn't tighten them enough because the guide was stating in bold letters: "Tighten carefully, as you might crack the printed part (idler)!!!"
Two days ago, the MMU2S was showing a similar issue. I was, again, checking everything in the Unit and tested everything again. Long story short, the Leftmost ports of the mmu2s didn't worked well because the idler has lifted just a bit, enough to work when the mmu2s unit was unattached from the printer frame but not working when attached. So the Idler was crooked, whyever.
At this point, i don't really know what i should think about the MMU2S Unit. I have wasted a lot of time of debugging the Unit, which could easily turn out to be 60 hours or more in total and it still doesn't work reliably.
When looking at other posts, it looks like it's still a Beta device rather than really End-User ready.
Best Regards
RE: I am frustrated with the MMU2S
Man, I took a week off work and I spent about 40 hours that week, and since then another 20-30. All I have learned so far is the stupid behavior of the thing. I have printed tons of mods to assist with all kinds of issues. I have wasted so much time debugging it as well, I completely feel you on this thing. Definitely join the unofficial Prusa3d Discord if you haven't already and ask the #multimaterial channel for help.
The MMU2S is a fickle mistress. I haven't given up on it though. I still foolishly have hope and there is always "one more thing" to try.. I have never had a fully successful print, whether 6 hour print or 24 hour, it always seems to fail half way in.
Recently the MK3S+ upgrade arrived and I also got a Dragon v2 hotend - High Flow, that might help with stringing. Also the MK3S+ IR sensor is supposed to fix those false positives (and real positives that are missed) with the MMU2S unit.
RE: I am frustrated with the MMU2S
Hola, me pregunto: Los técnicos de Prusa, leerán estos post?
Compré hace meses la MMU2s y con todo lo negativo que he leído, tengo dudas de intalar.
Saludos
Max
RE: I am frustrated with the MMU2S
Doesn't sound that good as well. :-/
Thank you for the Discord mention.
I would really like to know how they achieved the 600k filament changes with more than 93% of successful print as stated on the MMU2S shop page.
RE: I am frustrated with the MMU2S
@rhettbrodeur
Hi Rhett,
If I understand correctly, you intend to use a Dragon Hi Flow extruder with MMU2.
the Hi Flow extruder has a larger Melt Zone, than the standard Extruders,
I believe this will require more Purge Filament to clear the old filament, on filament changes
this is why I didn't fit the Hi Flow to My Mk3S with Palette2...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: I am frustrated with the MMU2S
@maximiliano
Hi,
Prusa Technicians rarely read these forums,
they work at the Prusa GitHub sites for the relevant products.
If you have suggestions or requests that may be the best place to raise your queries...
this site is for Peer to Peer support from other Prusa Owners...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: I am frustrated with the MMU2S
@Joantabb i think it would make sense for the technicians to check the forum from time to time or use the mmu2s themselves on a regular basis as they did for the mk3s for the mass production of parts. Maybe they would also benefit from it by not needing to exchange the filaments that often if they just put in 5 rolls of identical filaments into each port and let the printer do it's job continuously 😀
RE: I am frustrated with the MMU2S
@joantabb
Thanks for letting me know, I guess I will find out shortly! Even if I have to adjust purge settings, I'd rather do extra purge than deal with all the stringing that has been happening. Almost every hour in printing with MMU it stopped due to stringing.
RE: I am frustrated with the MMU2S
@pecadis
Different folk have different experiences, I get many successful prints with MMU1, MMU2S and Palette2S Pro...
but My Use case is possibly different to yours...
in most cases I sue the MMU's for surface dressing, not large model colouration.
I guess this minimises my filament changes.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: I am frustrated with the MMU2S
@joantabb
Muchas gracias por la información
Saludos
RE: I am frustrated with the MMU2S
@JoanTabb
i absolutely agree with your statement, everybody's need and situation is different so it is hard to compare. It is also very likely that i screw up at some point which caused a chain reaction of issues.
On the other hand, i was only printing models with 16 filament changes total between only two filaments, i don't think that this should be the issue. At least, i would expect such a device to be able to handle this small number of changes, also because it isn't engaged during the print with one filament. That is basically where my frustration is coming from: "Why the heck is the MMu2s Failing when only so few changes are needed?"
RE: I am frustrated with the MMU2S
So sorry to hear about all your trouble!
I only got me a clone because I was not ready to fork out all that cash reading about all the issues others have experienced. Frankly, I was genuinely scared of diving into the multi-material printing area, haha.
It actually turned out pretty well. No major problems, occasional trouble with filament swap (we're talking one, maybe two cycles per print with dozens of swaps), which was down to too tight PTFE tubes that had problems letting through the sometimes more bulgy filament tips.
It only took me a couple of hours to get it all working and upgrading my mk3s to mk3s+ with the mmu2s filament sensor chimney. Since then I've printed loads of multi-colour things with only a total of an hour perhaps spent on maintenance of the MMU2 unit (cleaning up, re-aligning, replacing the selector with a better one to minimise false positives on the filament sensor, etc.).
The only thing that does annoy me, and you mentioned it as well, is the error notifications. The MMU2 starts flashing its LEDs and the printer says 'MMU needs user attention' (or something similar) but doesn't say what the actual problem is so one needs to do some guesswork based on what was expected and what you actually see happened...
RE: I am frustrated with the MMU2S - I will deinstall them.
I am also extremly frustated with the MMU2S. I will deinstall the MMU2S and I Hope that I will get may MK3S back.
First everything went well - two easy and absolute successful prints using three colors. I was pleased by the results and happy.
But since then - trouble over trouble. Filament loads - does not load. Spent hours of hours in trying quite a lot of different things. Adjusting and checking the sensors, tried different filaments, and ...
Repated the successful prints with the same filaments. No success - to many problems during filament changes. Even working with one single colors becomes a terrible thing. I will remove this piece of hardware.
RE: I am frustrated with the MMU2S
In the meantime I deinstalled the MMU2S and received my good working Prusa MK3S+ back. 😀
In a first attempt I disconnected the cables from the MMU2S on the MMU2S but this caused the printer to request random filament changes (the objects have been sliced w/o MMU2S). IMHO this may be caused by some interference on the - open - cable. Removing the cables in the Einsy and ervertings wents well for me.
Maybe in several months I will give the MMU2S a further chance.