Problem with loading filament, except 1
I had a few successful prints but the IR sensor wasn't working. I replaced the idler "door" with the trimmable one, and I was able to calibrate/align the sensor.
Since then, I can load filament 1 no problem (to nozzle, or whatever) but 2-5, when loading to nozzle, no problem through the MMU2S, but has trouble pushing into the extruder, and I get a loud clicking noise. I've even put the old door back, and it's the same. I've tried adjusting the tension from very loose to tighter, but it's the same, smooth loading filament 1, not so for the others. The only difference I can spot is that the head is in a different position, so the angle of "attack" from the top to the head is slightly different.
I've read a lot of posts here, but other than "get the ir sensor calibrated and idler tension right" is there a procedure I can do to check and calibrate everything? (AND, I wish there were pinned posts for such FAQ...)
RE: Problem with loading filament, except 1
What do you mean "the head is in a different position"? You mean the tip of the filament? When it enters the extruder body? That doesn't make much sense to me given that the entry point is controlled by the PTFE? Have pics?
You mention adjusting the tension, is that just on the idler door for the extruder or on the idler cover with the MMU? I've had issues when I don't have the idler cover adjusted right where 1 or 5 will be happy, but others don't feed correctly.
Given that you had to print a new idler door so you could trim the flag (so did I), my first guess is that your flag might need a bit more adjusting. It kinda sounds like you are getting lucky with filament 1 while the others are moving the door enough to trip the extruder but before they are far enough to get picked up.
When it does this, what happens if you manually feed the filament into the MMU? Does it advance enough to be caught?
RE: Problem with loading filament, except 1
Thanks @gnat, Your posts have been the most helpful to me to understand what's going on.
I can almost always get it to load, but I think you are right, the ir sensor is probably to blame. The regular "calibration" looks ok (1 when the filament is engaging the gears, and 0 otherwise) but sometimes on a filament change it does a feed in, backs it out, and says there is trouble (I assume this is that 50-45 dance mentioned in some of your other posts.) I can usually get it to work by squeezing in the flag part of the idler door (keeping the sensor triggered, I assume) until it finishes feeding.
I did notice friction in some of the feeder tubes, so I printed out the festo holder you mentioned (I happened to have the 10mm festos from working on Enders and CR10s). I'm trying a 2 color test print now.
RE: Problem with loading filament, except 1
Thanks @gnat, Your posts have been the most helpful to me to understand what's going on.
We aren't a community if we aren't helping each other and the community is why I bought into Prusa over other (more expensive) printers I was looking at.
I can almost always get it to load, but I think you are right, the ir sensor is probably to blame. The regular "calibration" looks ok (1 when the filament is engaging the gears, and 0 otherwise) but sometimes on a filament change it does a feed in, backs it out, and says there is trouble (I assume this is that 50-45 dance mentioned in some of your other posts.) I can usually get it to work by squeezing in the flag part of the idler door (keeping the sensor triggered, I assume) until it finishes feeding.
Yeah that definitely sounds like the IR flag isn't dialed it quite right. Can you get through a single filament print OK with no issues? For me I had to disconnect the MMU entirely and print as a plain MK3S (though with the MMU tower) to get my IR flag dialed in right. Similar to you all the static tests were good, but once the extruder started moving around it would throw false runout events from time to time as vibrations made the flag move "just enough".
I did notice friction in some of the feeder tubes, so I printed out the festo holder you mentioned (I happened to have the 10mm festos from working on Enders and CR10s). I'm trying a 2 color test print now.
I finally got that added myself this weekend. Except that you can't get the idler cover open without removing the festos I like it a lot. Unfortunately that was timed with moving my spools to a "better" location (above the printer) and now I can't get through a Benchy again 😣
RE: Problem with loading filament, except 1
I finally got that added myself this weekend. Except that you can't get the idler cover open without removing the festos I like it a lot. Unfortunately that was timed with moving my spools to a "better" location (above the printer) and now I can't get through a Benchy again 😣
Ugh (for the no benchy) Yeah, my single filament prints are fine. I ordered some "bigger (2mm inner diameter)" PTFE tubing but in the meantime, I replaced the tube between the mmu and extruder with some capricorn. Ironically it's a tighter fit, but it's really slick, and seems to be working ok most of the time.
I managed to get through one MM print (2 colors) and then had problems half way through another one. In one case, the mmu head didn't seem to be lined up with the feed slot, though I suppose it could be something to do with curvature of the filament. (I couldn't manually shove it through the finda).
I've tried slots 1-4, and 1,2, and 4 are working now, but 3 doesn't feed at all. It's lined up ok, and if I press my nail against the filament on the mmuextruder gear, it will go forward, but for some reason the bearing isn't pressing on the filament hard enough.
RE: Problem with loading filament, except 1
I've tried slots 1-4, and 1,2, and 4 are working now, but 3 doesn't feed at all. It's lined up ok, and if I press my nail against the filament on the mmuextruder gear, it will go forward, but for some reason the bearing isn't pressing on the filament hard enough.
Ugh. That sounds like maybe the tension bolts might need to be a bit tighter. I hate when I have to open that cover as it always means a bunch of failed tool changes until I get it dialed in just right again. Too tight and it eats filament on the ends. Too loose and the inner filaments don't get picked up and moved well. A 3rd bolt in the center could be helpful for a more even tension and some way to separate adjusting the tension from holding the door in place so you don't have to readjust every time would also be really nice.
RE: Problem with loading filament, except 1
MuMu and I are taking a little break. Anger issues....
Got two good prints out of it (not super ambitious, 2 colors, changes only in the first 4 layers) went to dinner and wouldn't feed anything.
Removed it. Thinking about installing some plug cables so I can reattach to fiddle when I cool off a little.