MMU2S Unloading Issue
I am running into issues with filament unloading. The tips of the filament look fine and everything appears to be working properly but every so many load/unload cycles it seems the filament doesn't come all the way out of the bondtech gears and the MMU eats the filament causing a fail and it can no longer unload. I end up pulling the filament out and cutting at the area that was eaten away and continue printing. I wouldn't be bothered if this was an infrequent thing but it seems to happen about 1 in 20 to 30 tool changes. It seems that if the filament would have just come out of the bondtech gears just a little further it would have come out no problem. Any recommendations would be helpful.
RE: MMU2S Unloading Issue
Filament sensor in the extruder would be my first place to look. Check to make sure it isn't flickering (should be solid on when filament present).
RE: MMU2S Unloading Issue
@ticktock
When I have filament loaded the IR Sensor stays at a solid 1 without any problems.
The question I have and maybe this is where I may have it wrong, should I calibrate it with the filament just pushing the gears in or with the filament fully loaded in? At this point I insert the filament into the gears then I adjust the chimney to make sure I get a good solid reading, should I instead be trying to get a solid reading with the filament just pushing on the gears? Thanks!
RE: MMU2S Unloading Issue
@sindarius
According to this:
https://help.prusa3d.com/article/wprwemqsmj-ir-filament-sensor-calibration
you use the 1.5mm allen key. I, however, keep mine so it is just barely a "0" (light off) when no filament is present and a "1" (light on) when there is the slightest pressure between the gears (I push on the tensioning bolt to feel the pressure and see how much motion before it turns on). Just finished a 32 hour print with 3 colors without a single intervention. I also have the following two mods:
RE: MMU2S Unloading Issue
@ticktock
Thanks, I've looked at some of this before. I will take a look at the mods you have. I do like the LED idea since you can't always get to the sensor screen and I'll take a look at that door mod.
RE: MMU2S Unloading Issue
A quick follow up for anyone interested
This may end up being completely anecdotal but I ended up picking up a moons extruder motor (1A 1.8deg) since I have noticed the LDO motor running a tad hot. I am currently sitting at over 200 tool changes without a single failure. Honestly I can't say 100% that was the solution because I had to rebuild the whole extruder to do the motor swap so it could have been almost anything in there.
As a side note the moons stepper has never passed 40c while printing.