MMU2s Failing to Load Filament into Extruder Consistently
 
Notifications
Clear all

MMU2s Failing to Load Filament into Extruder Consistently  

  RSS
JasonPrints
(@jasonprints)
New Member
MMU2s Failing to Load Filament into Extruder Consistently

Hi all,

Extruder is not accepting filament. The bondtech gears grind and no filament is being fed through the extruder. I verified that the sensors were working according to the initial startup tests and during a print attempt. I installed the new 1.85 ID ptfe hotend tube and changed it out from the orginal 2 ID tube but still had no success. In fact it was worse with the new 1.85ID PTFE tube. I utilized other prusa forum posts that suggested to use the new included 1.85 ID PTFE hotend tube. The rationale behind this was that it prevents the filament from retracting with too large of and end which prevents it from retracting back into the PTFE tubes when ejected.(basically controling the size of the end from getting to big so it feeds right) I ensured that the tips were cut correctly before we started loading filament but even then it still failed to fed into the extruder.  If we insert the filament by hand into the chimney it feeds fine but when it goes from the festo connector into the chimmey, Could it be too much resistance in the festo PTFE tube. The five PTFE tubes from the buffer seem to have a reasonable amount of resistance, so Im thinking festo portion if any. what do you think?

Jason

Posted : 19/06/2021 11:49 pm
JasonPrints
(@jasonprints)
New Member
Topic starter answered:
RE: MMU2s Failing to Load Filament into Extruder Consistently

Hello. We contacted prusa support and know our next plan of attack. We are gonna try to increase the size of the ptfe tube to a 3 mm I'd. And try to decrease the resistance of the overall system.

 

Posted : 20/06/2021 3:19 pm
GuyH
 GuyH
(@guyh)
Eminent Member
RE: MMU2s Failing to Load Filament into Extruder Consistently

I would recommend this mod.  Makes all the difference with loading the filament to the gears.  

https://www.prusaprinters.org/prints/3676-mmu2s-extruder-mod-feeds-almost-any-tip-no-jams-fo

Posted : 20/06/2021 9:55 pm
JasonPrints
(@jasonprints)
New Member
Topic starter answered:
RE: MMU2s Failing to Load Filament into Extruder Consistently

https://www.hcd.net/prusa-mmu2s/Prusa-MMU2S-Reliability-Modifications.htm

The tech support linked us this to maybe make more mods too. Seems like everyone is moving towards 3mm ID tubing.....

Posted : 21/06/2021 12:27 am
ssill2
(@ssill2)
Prominent Member
unnecessary

I've not found it necessary to replace the tubing from the mmu to the extruder or any of the tubes inside the mmu.  I use 2mm ID tubing out the back of the MMU.

The only mods *I* feel are necessary are:

The M10 PTFE connector mode so the tubes on the back fit with festo connectors.

The brackets for horizontal mounting of the MMU.

I tried 3mm ID tubes but I found it gave the filament too much play on the back side of the mmu so it was hard to feed filament in when loading filament initially.  2mm ID tubing seems to be fine.

I did at one point try the selector with magnet but I got rid of that when I reprinted my MMU parts in a different color. 

This config is currently working great for me:

Posted : 31/07/2021 2:08 pm
Share: