User talk:GreenEllipsis/MMU2S

This content only covers the MMU2S. If you have an earlier version of the MMU, consider upgrading to the MMU2S.

Remedying Printing Problems

Pausing Print without Creating Problems

When pausing the printer from the user interface, the MMU seems to obsessively load and unload the filament. What is going on and how do you safely pause a print job? [work in progress]

Strings on Filament Tips

• Prusa: increase cooling moves. Decrease nozzle temperature.
• Klathmon: Too long of strings? Jams going IN to the nozzle? Decrease temps, increase unload speed at start to 120, decrease cooling moves to 1 (multiple cooling moves tends to create long lumpy strings for me). [1]
• Try 0Calvins settings

Filament not Detected at IR Sensor

• Clean extruder
• Calibrate IR Sensor per Prusa
• Reduce Tension on Extruder Screw
• Modify IR Sensor to increase sensitivity

Recovering from MMU2S Errors during Printing

LEDS:

* * * * * Selector can't move due to filament sensed in selector
* _ _ _ _ Filament 1 load failed
_ * _ _ _ Filament 2 load failed
_ _ * _ _ Filament 3 load failed
_ _ _ * _ Filament 4 load failed
_ _ _ _ * Filament 5 load failed

In general, determine cause of problem, fix it, press the MIDDLE (retry) button. It should go to * . Press the RIGHT (resume) button.

• Does position of LED match current filament on display? If no, skip ahead.
  • Is there PTFE tube empty? If no, skip ahead.
    • Is the filament sensor LED lit? If no, skip ahead.
      • Possible causes:
        • Debris anywhere on the filament path. Check and clean the entire filament path and retry.
        • A notch in the filament. Trim the filament above the tip and retry, clear the idler gear and extruder gears and retry.
        • An oversized, messy or stringy tip. Trim the tip and retry. Tune the filament parameters before the next print.
        • A mis-calibrated selector filament sensor. Re-calibrate the sensor and retry.
        • A mis-calibrated extruder filament sensor. Re-calibrate the sensor and retry.
        • Tangled filament prior to entering selector
    • [work in progress]
  • PTFE tube has filament
    • Possible causes:
      • Stringy tip caught in extruder (Extruder filament sensor value is 0)
      • Fat tip caught in filament path (Extruder filament sensor value is 1)
      • Idler assembly tension too light
      • Notch in filament in selector (probably caused by one of the previous)
• [work in progress]

Retrying a Failed Filament Load

• Re-insert the filament and feed it forward until it enters the idler assembly.
• Press the MIDDLE retry button until the lights solid orange, then release it.
• Gently pushing the filament from the rear until the idler grabs the filament.
• Does the LED flash orange, then green? If no, skip ahead.
• Press the RIGHT resume button until it lights solid orange, then release it.
• The LED should light solid green and the print should resume automatically.

*  *  *  *  *   Selector or filament(?) motor overcurrent detected

• Prusa: video
• GreenEllipsis: Reduce tension on idler assembly by backing out spring-loaded screws

Wrong filament loaded

1. Press CHANGE FILAMENT from the i3 menu. The filament will unload.
2. Press the RIGHT or LEFT buttons on the MMU to move the selector to the correct filament.
3. Press the MIDDLE button to load the filament.
4. Press the knob on the i3 to load the filament to the nozzle and resume printing.

MMU2S Modifications

Extruder

• more sensitive IR filament sensor

PTFE Tube Assembly

Generally, modifications involve increasing the inner diameter of the filament path and chamfering various locations.

• FESTOS or pneumatic couplers
  • Flav1u_ drilled his to 2.5 mm.
  • GreenEllipsis drilled his to 7/64 inches.
• PTFE tube diameter
  • ANTALIFE talks about why
  • replacing the stock PTFE tube with a tube that his the same 4 mm outer diameter, but a 3 mm inner diameter.

Selector

• Button for MMU2S reset button
• Captive screw covers for idler tension screws
• Labels for left, right and middle buttons

Filament Buffer

• Gravity assist

Firmware

• Dribbling. ANTALIFE talks about why
• MMU Firmware: Enhancements to MM-Control-01 https://github.com/TheZeroBeast/TZB-MMU2S-Firmware/releases
• MMU Firmware: Merge of TZB and Prusa MM-Control-01 https://github.com/Ruhkukah/Prusa-Firmware/tree/TZB-Full-Ruhkukah-3.9.1

Additional References =

https://help.prusa3d.com/en/article/mmu-loading-failed_2135 https://help.prusa3d.com/en/article/mmu-needs-user-attention_2139