MK4S Extruder motor stops mid-print
Last month I upgraded my mk4 to a mk4s (with the kit from Prusa). Until yesterday, the printer works perfectly. Now around an hour or two into any print, the extruder stop feeding filament. (up to that time, the part is printed properly). The printer keeps on moving normally, no error indication. Observations:
(1) The printer passes all of the built-in tests.
(2) The filament spool in rotating freely, filament is not jammed.
(3) The nozzle is not jammed - After stopping the print, I can use the control panel to purge, or to reload the filament normally.
(4) During printing, it seems the extruder is NOT rotating; One time I opened the 'gate' on the extruder and the driver gear was not turning.
(5) Filament is not marred, and there is no 'clicking' sound from the extruder (which normally would occur if the fillament was jammed). There is no debree from the filament embeded in the gear or filament path.
(6) Ambient room temp is around 76 deg F (around 24 deg C). No enclosure.
Any ideas what might be wrong?
RE: MK4S Extruder motor stops mid-print
That’s a tough one! Sounds like you’ve checked the most likely points. Possibly, the motor connection to the love board needs to be reseated, or the love board itself could be bad. Maybe check your planetary gear alignment and try the gear calibration sequence again. Best of luck! There’s always Prusa Chat if you need more help.
MK4S/MMU3
RE: MK4S Extruder motor stops mid-print
Contact Prusa support. I had the same issue with two of my MK4S (upgraded from 3S->4->4S). In my case the extruder motors were faulty and replacing them fixed the problem. I had the exact same findings as you with the extruder just stopping mid print, yet I was able to purge the filament out once stopped. Albeit, I did notice in my case a small blob would come out when purging initially.
RE: MK4S Extruder motor stops mid-print
Thanks for the encouragement, and the
Just to keep this thread open - I'm in the middle of re-building the Extruder; The gearbox was clean, but is was dry - no lube! Right now I'm waiting for a 'grease kit' to arrive from Prusa, then I'll finish the rebuild, and try another print. Thanks for the ideas!
RE:
Could not be the extruder motor wiring? During the print the extruder is shaken so the wire could be broken or bad connector contact.
Check the extruder motor plug and wire.
Use the longer purge command and try to shake the motor wire and connector. We will see what happens.
RE: MK4S Extruder motor stops mid-print
Thanks to everyone who offered suggestions. Checking the wiring was a good idea, but I actually had done this early on - this wasn't my problem.
I Finally figured out what was happening.
First, an apology - In retrospect, believe I misreported the symptoms - I believe the gears in the extruder *were* always turning.
The pulleys on the idler arm were worn down (visibly so). Close observation showed that intermittently (when the two pulleys aligned in the right combination?), neither one would hold the filament against the Extruder gear. The filament would stop feeding, but *not* grind on the gear.
The fix was to REPLACE the pulleys on the idler arm, which were visibly worn down. I've just completed about 4 hours of printing without a problem. Hurahh!!!