Repeated unexpected manual filament change  

RE: Repeated unexpected manual filament change

Pretty rare problem.  I would chat with support.  

RE: Repeated unexpected manual filament change

In looking at the firmware source code, I think this is key:

/*!
### M600 - Initiate Filament change procedure <a href="https://reprap.org/wiki/G-code#M600:_Filament_change_pause">M600: Filament change pause</a>
Initiates Filament change, it is also used during Filament Runout Sensor process.

My gcode doesn't contain an M600, so I bet that it's triggered by the "Filament Runout Sensor" process. It'd be great if someone had any thoughts on what trails I should follow here.

RE: Repeated unexpected manual filament change

Posted by: @sean-prusa

Hi! I've had my MMU2S unit ~working for a couple months now, and my MK3S for almost a year.

One problem that I am having with varying frequency is a spurious filament unload/load cycle, as if I didn't have an MMU2S at all. I'm printing a single-color PLA print with the "Original Prusa i3 MK3S MMU2S Single" Printer profile, from "PrusaSlicer-2.2.0+-202003211132"

During the first couple hours of my current print job, it worked mostly fine. But now, it's doing this cycle on nearly every layer. After it finishes with the layer, it moves to (max-x, min-y, cur-z) and starts beeping repeatedly, with the message:

"Remove old filament and press the knob to start loading new filament"

It sometimes starts retracting the filament, sometimes doesn't. Once I press the button, then it shows:

"Loading filament 4" for a few seconds, while the filament advances towards/through the extruder. Then the display changes to:

"Changed correctly? >Yes >Filament not loaded >Color not correct"

After I click "Yes", it resumes the print without trouble, printing the next layer. Then the same trouble happens again.

I am using the gcode straight out of PrusaSlicer, on an SD card. If it'd be helpful, I could share it or look for specific commands.

The support menu reports:

Firmware: 3.9.0-3421

1_75mm_MK3

EINSy_10a

E3Dv6full

Fil. sensor v0.4 or newer

MMU2 connected FW: 1.0.6-372

Fail stats and Fail stats MMU2 report no issues.

I suspect this is some kind of combined hardware/software issue. I'm wondering if there is some intermittent problem with my hardware, but it results in this bizarre software symptom, so I can't figure out the problem.

Any ideas?

 

The most common causes for such problems are incorrectly adjusted sensors or dirt around them (filament strings).

RE: Repeated unexpected manual filament change

Thanks. I wrote to [email protected], I'm not sure if that's the right procedure to chat with support.

WRT to incorrectly adjusted sensors/filament strings. I checked that the IR sensor does a good job of being 0 when there is no filament in the extruder and 1 when there is filament. (By using the support > sensor menu and inserting/removing filament.) I unscrewed the door and confirmed there isn't any dirt/filaments in the extruder.

I readjusted my FINDA depth (recalibrating with and without filament in the selector carriage) - maybe that will matter?

Is it know-able if my problem can be triggered specifically by one or the other sensor having a false positive/negative?

Thanks, Sean