Mmu2.0 random issues
Ok so been using the mmu2.0 for a couple weeks now. I like it, certainly dont love it as its buggy af sometimes.
1 issue I know is being researched is the selector stopping at incorrect filament number. Happened to me like 2 times in beginning then haven't seen it since. (Prob jinxed myself).
Another issue I'm having is something is triggering a traditional filament change sequence (print head moves to front right of printer, chirps like a pissed off bird, yea that one) while using the mmu, both in normal multi material use settings and in the single material mmu settings. This happens at random, sometimes wont happen at all, sometime happens 4 times within a minute.
Not sure what causing this, and dont know what to look at (looking at all the text dialog makes me dizzy when I dont know what I'm looking for lol).
Has another user come across this?
For instance, I'll DL a file from thingy, latest one was a vase to test out my petg colors to see what settings work with what colors, I sliced it in latest slic3rPE, vase mode, generic pet selected, single mmu setting.
Saved gcode to sd card. Started print, ran perfect for first 1.5 hrs. After that, the printer started to ask for filament change.
The nozzle extruder retracted, machine chirps at me to remove filament immediately. Have to manually rewind filament back through mmu, the selector moves off to side, mmu extracted filament a few inches, had to retract manually again, hit button on mmu unit, selector moves back, sucks in the filament and the machine asks of color is ok, I click yes, so it starts print again.
Did this for next 2 layers (so like 4 or 5 times). After it started again. I aborted print.
Not sure what to look for that's causing it. Happened on a couple models I made in fusion360 and on a few models I DL from thingy. Next time it happens I'll take a video and pics to post so yall can see exactly what's going on, but am at work at moment.
Any ideas?
Re: Mmu2.0 random issues
Ok so been using the mmu2.0 for a couple weeks now. I like it, certainly dont love it as its buggy af sometimes.
1 issue I know is being researched is the selector stopping at incorrect filament number. Happened to me like 2 times in beginning then haven't seen it since. (Prob jinxed myself).
Another issue I'm having is something is triggering a traditional filament change sequence (print head moves to front right of printer, chirps like a pissed off bird, yea that one) while using the mmu, both in normal multi material use settings and in the single material mmu settings. This happens at random, sometimes wont happen at all, sometime happens 4 times within a minute.
Not sure what causing this, and dont know what to look at (looking at all the text dialog makes me dizzy when I dont know what I'm looking for lol).
Has another user come across this?
Both issues happened to me too. Sadly, I can not reproduce it. And without reproducibility it is hard for the dev’s to fix the bug.
Re: Mmu2.0 random issues
I don't know about the selector stopping at the wrong filament, but I think when the system asks for a filament swap, it's because the FINDA sensor has momentarily stopped sensing the filament. You could try moving the FINDA probe a little lower.
I had this happen a couple of times, one of them happened when the filament was caught at the spool and the printer was struggling to pull it with the bondtech.
Re: Mmu2.0 random issues
Yea I guess slightly lowering finda may be an option. Try that tomorrow morning when I run another print Least I'm not only one seeing those issues and yes, it's very random and cannot be reliably duplicated to actually diagnose the problem. Did a 6 hr petg print today 0 issues, where as yesterday same filament had it happen 2 times (the auto unloading part).
Oh the joy lol
Anyone have any leads on a better spool holder setup for mmu2 or at least filament guides? This stock system is pretty obnoxious imho and when the filament ejects after printing or a tool change that 90 degree swing arm locks the filament and I'm seeing it put almost a 90 degree kink into filament. So far no issues when filament gets pulled back in but would like to see a change in this.
Sucks being away from house 15 hrs a day for work cause leaves me very lil time to work with my printers.
Re: Mmu2.0 random issues
Sorry I didn't respond here, I thought with all the other posts it would have been covered:
In my experience, leaving the optical sensor in the mk3 on will cause it to occasionally trigger a filament change. I've tried changing the lighting, but I think it's just some hiccup in the code.
Turn off the sensor and it should stop randomly reloading.
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Re: Mmu2.0 random issues
my feed back from before MMU2.0 in just using the MK3.
turn off the filament sensor and layer shift detection. both of these cause numerous problems for me early on. random failures and prints that should of been ok were ruined. pretty much from the second week of me using the MK3 both of those were disabled.
on to the MMU2.0
if there is outside pressure on the selector the stepper motor will skip. first i would make sure the selector can move free. pull out the selector stepper. make the the filament is out of the way and start sliding the selector back and forth. make sure it is REALLY free, i had to go back and slightly drill out the shaft holes for the selector so that the shafts were floating parallel. put a drop of bearing oil on these shafts also. watch your knife make sure it didn't slightly shift in the holder... (my opinion is the cut out for the knife holder needs to be .1" deeper then it is) if the knife moves it can dig into the lower PETG and then the selector gets slightly hung up and selector stepper starts to skip steps.
everything is actually dependent on how much friction is on the filaments ability to move from the spool to the extruder. everything has to be as free and smooth as possible on all 5 tubes and spools.
if you using the stock spools with the aluminum shaft in the center stop right there and get these:
https://www.thingiverse.com/thing:3113520
these use the same prusa parts but in a different configuration. it takes a HUGE amount of friction out of the load and unload system which leads to skips and jams and the pulley striping out the filament. most of the time the problems are caused by the filament jamming in some way. if a little is sticking out in the selector and the blade misses it the selector can randomly hang up and jam it doesn't take much and then everything starts to go out of sequence and you get a failure.
i would go back and by hand start testing everything make sure it is free moving and you don't feel the filament catch on something. ( i spent like a hour hand shaping my extruder input around the filament sensor because the tips kept catching just enough to cause pulley damage to the filament which nuked the entire system). use bearing oil sparingly but with purpose. the shafts have to be lightly lubricated and everything moving free with no feel of chugging or skipping.
after i completed my MMU2.0 i honestly wished i could of gone back and cleaned up the selector body even more before assembly. the entire mount in the selector for the TPFE tubes is too tight and i should of drilled out the bottom plate so the tubes fit just nicely in there and i should of cleaned the hell out of the FINDA and allow that ball bearing to float even better. but i was too overwhelmed with the entire MMU2.0 and MK3 extruder upgrade all at once to really put my attention to one part at a time. i just find the whole MMU setup to be right on edge of function with zero margin for errors as one Step being off and the entire system fails.
another thing is the material condition. with all the movement if you use PLA brittleness becomes a factor, a kink or fracture is going to cause a failure. either make sure to go to fresh sealed filament for the first prints to get a feel or bake your old stuff and get the water out of it.
if your pla is breaking like macaroni then toss it to the side.
“One does not simply use a picture as signature on Prusa forumsâ€
Re: Mmu2.0 random issues
my feed back from before MMU2.0 in just using the MK3.
turn off the filament sensor and layer shift detection. both of these cause numerous problems for me early on. random failures and prints that should of been ok were ruined. pretty much from the second week of me using the MK3 both of those were disabled.
on to the MMU2.0
if there is outside pressure on the selector the stepper motor will skip. first i would make sure the selector can move free. pull out the selector stepper. make the the filament is out of the way and start sliding the selector back and forth. make sure it is REALLY free, i had to go back and slightly drill out the shaft holes for the selector so that the shafts were floating parallel. put a drop of bearing oil on these shafts also. watch your knife make sure it didn't slightly shift in the holder... (my opinion is the cut out for the knife holder needs to be .1" deeper then it is) if the knife moves it can dig into the lower PETG and then the selector gets slightly hung up and selector stepper starts to skip steps.
everything is actually dependent on how much friction is on the filaments ability to move from the spool to the extruder. everything has to be as free and smooth as possible on all 5 tubes and spools.
if you using the stock spools with the aluminum shaft in the center stop right there and get these:
https://www.thingiverse.com/thing:3113520
these use the same prusa parts but in a different configuration. it takes a HUGE amount of friction out of the load and unload system which leads to skips and jams and the pulley striping out the filament. most of the time the problems are caused by the filament jamming in some way. if a little is sticking out in the selector and the blade misses it the selector can randomly hang up and jam it doesn't take much and then everything starts to go out of sequence and you get a failure.
i would go back and by hand start testing everything make sure it is free moving and you don't feel the filament catch on something. ( i spent like a hour hand shaping my extruder input around the filament sensor because the tips kept catching just enough to cause pulley damage to the filament which nuked the entire system). use bearing oil sparingly but with purpose. the shafts have to be lightly lubricated and everything moving free with no feel of chugging or skipping.
after i completed my MMU2.0 i honestly wished i could of gone back and cleaned up the selector body even more before assembly. the entire mount in the selector for the TPFE tubes is too tight and i should of drilled out the bottom plate so the tubes fit just nicely in there and i should of cleaned the hell out of the FINDA and allow that ball bearing to float even better. but i was too overwhelmed with the entire MMU2.0 and MK3 extruder upgrade all at once to really put my attention to one part at a time. i just find the whole MMU setup to be right on edge of function with zero margin for errors as one Step being off and the entire system fails.
another thing is the material condition. with all the movement if you use PLA brittleness becomes a factor, a kink or fracture is going to cause a failure. either make sure to go to fresh sealed filament for the first prints to get a feel or bake your old stuff and get the water out of it.
if your pla is breaking like macaroni then toss it to the side.
Yea I started to double check things. That blade mount is bad design. Does need to have a more well defined locator for it. But checking that I realized I installed the blade backwards so if a lil bit of filament was sticking out the flat side of blade hit it and didn't cut.
Disabled the optical sensor as well.
Readjusted the find a again.
So far seems to be ok. Going onto the areas of friction next.
Need to drill out the 90 degree swing arms on stock filament guides. Way too much friction. Literally sounds like a skipping extruder from 2 of 5 units.
Afterwards need to sit and figure out this octoprint options. Have it hooked up, zero w installed, camera hooked up. Just need patience to figure out setting and want to use the mesh visualizer to check bed. But guess that's on another topic lol
Re: Mmu2.0 random issues
There are a bunch of remixes for the selector on thingiverse. people have made better designs for the blade holder, they also rounded and tapered some of the edges for the filament. i have not tried any of these yet.
I drilled out mine with a 2mm bit. to free them up i also spun the 3d printed swivel where the TFPE tubes go and i put a drop of plastic safe oil on it to free it up. then i replaced my spool holders with the remix from thingiverse, the spools now turn very easy.
watch for filament chipping in the selector body, i found if the tension was too loose or too tight you started to get these chips or flakes building up. i guess the setting for the correct tension is when you stop seeing them. i also noticed the left side tension spring has to be less then the right side because all everything is offset to the left in the selector body and more weight and tension falls on the left side.
for me i had bad luck with octoprint so i skipped it.
“One does not simply use a picture as signature on Prusa forumsâ€