Print not starting - MMU filament loading fails at the very beginning.
I have been using the MK3s with MMU for the last 4 weeks without any major issues. This afternoon, however, my printer has started to do the following when I try to start a print. (I have tried to solve this by switching filaments, etc., but so far to no avail).
1. The printer correctly performs the 9 point calibration and returns to the front left corner of the build plate.
2. Then the MMU pushes filament to the hot end.
3. Typically the printer now starts and makes two passes at the front of the build plate to purge the nozzle and get ready to print. However, since this afternoon my printer has stopped doing this pass and just pushes filament into a big blob under the nozzle, which remains stationary in the front left corner. Eventually the printer stops, unloads the filament, and tries again. After the 2nd attempt I get an MMU load error.
Any thoughts on what might be going on?
Thanks,
Georg
RE: Print not starting - MMU filament loading fails at the very beginning.
Will it let you get to the Support menu and show the Sensor info when it does that? That really sounds like the IR sensor isn't tripping to tell the MMU that the filament got that far.
If it does let you get to the sensor info, both FINDA and IR should be 1 when filament gets to the extruder. If IR is 0, that is the issue and you'll need to debug that.
RE: Print not starting - MMU filament loading fails at the very beginning.
Thanks. That seems to have been the issue. I disconnected and reconnected the IR sensor and cleaned out some filament bits and pieces from the motor area. Now it runs like a charm and the sensors all display a 1. I did notice that whenever my printer moves very quickly while moving from one print to another, the IR sensor flickers between 0 and 1, which makes me wonder if I have a loose connection somewhere.
Thanks, for now I am printing again!
RE: Print not starting - MMU filament loading fails at the very beginning.
Happy to help.
If you are seeing it flicker under movement that suggests that either the tower is not in quite the correct location or the IR flag isn't sitting where it ideally should.
If false IR readings are an abnormal thing, however, I wouldn't mess with it for now if it were me. Keep in mind, however, that if you start getting weird load issues (e.g. everything is clean, but it still doesn't want to load) or it stops mid tool, it would probably be best to start looking at the IR sensor then.