MK4 with MMU3 - "70% Feeding to fsensor step" - filament feed failure - high pitched buzzing from nextruder gearbox??
Hello Prusa Community!
New to 3D printing, so please forgive any missing details here...
I've been able to print successfully with my new MK4 with MMU3 for about 10-20 hours now using various filement MMU positions. Recently, I tried to print a model with the same filament and filament position that was being used previously. It was successful in loading the filament into the MMU3 without issue, however, when the step "Loading Filament" reaches the step 70% Feeding to fsensor I am getting a very loud buzzing sound from the nextruder. The only option to recover is to "reset". I've confirmed several things:
- Confirmed the buzzing was occurring well before any filament was being pushed through the insertion point on the top of the nextruder (so new filament feeding is not the issue)
- With the printer off, I opened the idler arm, confirmed there was filament on the gears that feed the filament - I've since cleaned this manually with tweezers, and after additional failed attempts I used canned air too
- Lastly, I got to this buzzing point, opened the idler arm out of frustration while it was buzzing, confirmed there was no movement of the gear that seems to grip/feed the filament
- At this point would people be pulling apart the planetary gear box, or what other ways would you be investigating the issue?
It's a very loud high pitched buzzing noise, and the nextruder is vibrating, so I'm doing my best to quickly restart before doing any more damage...???
Thank you for your thoughts! Hope this post helps others in the future.
RE:
Update: with the printer off, I pulled the three bolts holding the planetary gear box face plate on, I then put a finger and thumb on each of the two posts (one for each of the two small gears), I then gently turned the planetary gear box while the idler arm was down, and looked in to the gear that feeds the filament. As I turned the two small gears a melted bit of filament popped in to view, I removed it with the needle nose pliers.
From there I turned on the printer, attempted to print. That then let me do a "fsensor didn't trigg" (it seemed to try loading some filament, but it didn't make it all the way to the extruder). Then I made sure plenty of filament was available in the MMU3 feedback cassette, performed a retry, and we were back up and running!
Hope this post and update helps others!