Extruder motor stalling
Hi,
I have a Prusa MK3s which worked fine for over 2 years. In that time I managed to print more than 11 km of filament without any major issues.
But then a month ago I had this problem, where the extruder motor just stopped extruding while the other motors were working. That resulted in the incomplete print. So I tried a few different things:
- Fresh SD card and reslice a model - no change
- Performed a cold pull and changed the PTFE tube in the extruder - helped for a while but after some time E motor stalled again
- Changed the nozzle - looked like a problem was solved (I managed to complete a few 19h prints, which was impossible before) but then in another print the motor stopped after just a few hours of printing.
The motor can fail in 2 different ways:
- The motor is completely dead (unpowered). I can pull or push the filament in or out of the extruder by hand and can see the motor shaft spinning.
- The motor is just "shaking" or "jerking" in place (like a single phase was powered) and is not moving the filament at all.
I thought that the 1st failure mode could be the consequence of a blocked filament path (that is why changing the nozzle and PTFE tube helped somehow) - filament needs too much force to push into to extruder which leads to excessive E motor current which causes stepper driver IC to go in overcurrent mode - effectively shutting down the motor. Is this possible?
The second failure mode would also suggest an issue with the driver IC. I don't believe there is an issue with the wiring of the E motor because whenever it fails all I need to do to fix the issue is to reset the printer.
Can you please suggest what to do to resolve the issue? I am thinking of buying another Rambo board, but they aren't really cheap..
Thanks and best wishes,
Matjaž Tome
RE: Extruder motor stalling
It could be a broken wire between the motor and the Einsy. I believe you can plug the motor in the location of the Y motor and use the control to see if it moves.
First check the connection - a loose plug can be intermittent like your description.
Then the wiring - if you are lucky your stepper has a plug at the motor end - but if it's hard wired, many are, you will have to do a bit of soldering.
Finally if the above both fail, remove the gears and turn the motor by hand - you should feel the steps but it should otherwise be smooth with even resistance - if you feel grating or varying pressure an internal bearing has failed.
To test the circuit board cross connect as @robin_13 suggests.
Cheerio,
RE: Extruder motor stalling
Hi,
Thank you both for the advice. In the upcoming days, I will try this and report back.
RE: Extruder motor stalling
Hi all,
I checked the connection (also used a multimeter to check the continuity between the phases of the motor) and found no faults. I also removed steper from the assembly and tried to rotate it by hand. That also seemed ok.
After that, I have been using my 3D printer and I have printed for cca 50 hours since. Everything seems to work fine for now. It is possible, that the motor plug was loose and when I unplugged it and plugged it back again it solved the problem...
Anyway, thank you all for the help, if the motor starts to fail again, I will write a reply in this forum thread.
Best wishes,
Matjaz