What happened?
If during the filament load to nozzle process, the filament sensor in the extruder is not triggered, the printer will show the error.
How to fix it?
Assembly
- Remake the filament sensor calibration.
- Make sure that the PTFE tube is fully pushed into the Festo fitting, and that the fitting is fully tightened, with no gap.
- Open the extruder idler and make sure that there is no leftover filament in the extruder blocking the new filament from loading.
- Make sure that the PTFE tube is fully pushed into the Festo fitting.
- If you use an alternative MMU-to-Extruder PTFE tube, make sure it is not excessively long.
The original tube is 360mm long. The MMU will automatically adapt to tubes up to 380 mm, but will not work with tubes longer than that.
Filament
- The filaments must have a sharp tip in order to load properly into the printer. If the tip is deformed, bent, or larger in diameter, cut it off.
- Inspect the last 40cm (15") of each filament. Make sure there are no dents in it.
- If the filament is still not being pulled, check the assembly.
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3 comments
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Ball
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I at first thought my sensor was the problem but i realised filament wasn't even pushing fully through the tube. After opening the 2 mmu3 screws i could see that my filament was shredded up. It seems fixed after re aligning the 5 push gear things and keeping the 2 main screws with springs looser. A Spool snag maybe could cause this too? But yeah, look under your filament to check if its rounded/grinded up
Navara
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Needs to be updated for MMU3/MK4. Sensor calibration leads to documentation to a product officially declared obsolete (MK3S), not providing answers for MK4.
Also doesn't cover scenarios when slots 1-3 load fine (so the sensor is fine), but 4-5 fail to load (when filament tips are fine as the first three).
Also doesn't cover scenarios when slots 1-3 load fine (so the sensor is fine), but 4-5 fail to load (when filament tips are fine as the first three).
noelthe3rd
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Same exact problem. 1-3 works, 4 intermittently works, and 5 not much. I upgraded an mmu3 from an mk3s+ to an mk4 and had mixed success. Works pretty well with two colors, 3 only works some of the time and never 4 or more.
rojoPrint
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In case other people run into the same issue...I started getting this error and the issue ended up being that my extruder Bontech gear had come loose and was no longer feeding the filament into the extruder. I opened the extruder idler to look inside and the Bontech gear was completely loose from the stepper motor.