MMU2S: Filament does not reach MMU2
New MMU2S-User here too. I had a great experience with my MK3S and I was able to print just about anything!
Tried to install MMU2 and I am stuck ever since. Very often when loading a filament to the MMU2 it will not even reach the unit itself. So it does not even come out of the small hole BEFORE the selector and the BT-gears.
What I tried:
- Disassembled and reassembled five times.
- Checked the PTFE tubes: The filament moves with very little resistance through the whole tube.
- Loosened the screws holding the tubes to the unit: Even when very loose, it will not help.
- Used a hot drill (wrong end) to marginaly widen the part where the tubes are supposed to go in 0.5 to 1mm (Step 13: https://manual.prusa3d.com/Guide/6.+Electronics+and+MMU2S+unit+assembly/1041)
- I tried to either push the PTFE tubes in the holes with force or to just not push at all...
My guess is there is a lot of resistance in this part of the assembly. I have no idea what to try next...
RE: MMU2S: Filament does not reach MMU2
When you seated the PTFE tubes in to the MMU2S did you feel them seat? If they are being held in place only with the cover, they may be misaligned the tube goes in to the hole, you can feel it when it does, try turning it a little when you insert it. Make sure all of the tubes are not pinched in the path and when you push filament in with the unit open, you can see it coming in to the unit.
Hope this helps,
Ken
RE: MMU2S: Filament does not reach MMU2
Print this to replace the PTFE input:
https://www.thingiverse.com/thing:3233579
This was one of the things I did that made a huge difference for my setup.
EDIT: I ordered these fittings for it, which is what is listed in the thingiverse description:
The other thing I would ask is whether you are using good filament. If it is very uneven that could cause problems, obviously.
RE: MMU2S: Filament does not reach MMU2
I printed the part, and installed it this morning, but my filament is still not detecting at the hot end, I see it travel through the path in to the hot end, but inside the host end the IR sensor doesn't trigger once it is there and the bonstech gears do not pick up the filament to extrude it.
I did the calibration with the allen key, and the IR sensor detects properly for the key, but when the MMU sends filament down the lane, it does not detect.
RE: MMU2S: Filament does not reach MMU2
Thanks for the replies!
@magician-144: I never felt the tubes "seat". I probably also squeezed the tubes trying to push them in. I used a friends printer to reprint this big part and now I can really tell when the tubes are in. So I guess the bad printing from the shipped part was the problem.
@wpegden: This looks really interessting. I will print this and order similar fittings. Amazon does not ship to Switerland.
RE: MMU2S: Filament does not reach MMU2
Just to clarify is this progress? Before it was stuck further up, right?
For the IR sensor, you should be able to physically see the door start to tilt when the filament reaches the hot end. It's possible that with the allen key, the door is just tilted more than it is being tilted by the filament, so that the IR sensor picks up the allen key but not the filament.
I would go to the sensor screen (in support), and see what happens when you manually push on the lever at the top of the door. You want it to be the case that it is *always* at 0 when you are not pushing the lever (and nothing is in the extruder), but if you push the lever in a little bit, it is at 1. Then, when the filament gets pushed down, you should see the lever get pushed a little bit, and that should set it at 1.
RE: MMU2S: Filament does not reach MMU2
Hello wpegden,
Thank you, I did not know about the filament door latch, but it tests fine when I touch the top of the latch, it shows triggered, and when I take my finger off of it, it indicated unloaded.
Trying a first layer calibration again to see if I can make it work.
Thanks again,
Ken
RE: MMU2S: Filament does not reach MMU2
@wpegden
Yeah that mod is a must have!
The MMU2S is up and working, I hada gear chewing up the filament, also had some friction at work on another one so it wouldn't draw right to the extruder, fixed those and all is working!