Idler broke while loading filament for the first time
I was going through preflight check and my first filament wasn't loading cleanly. I swung open the MMU2 and adjusted the pulley position, and didn't notice any problem. Next time I pushed the filament in, it came out the front of the MMU2. Looking in, I noticed that the 2nd idler bearing was over it's pulley, rather than the left most. Opened up to debug and noticed this:
I guess I'll be trying to get my printer working as a single color printer now so I can reprint the parts!
Is there a way to get the Mk3 to ignore the MMU2? Just unplug the signal wire?
Re: Idler broke while loading filament for the first time
Closeup of the failure now that I have it extracted:
On the positive side, I can dial in my extruder upgrade without worrying about the MMU2, and then bring all the MMU2 issues in with a stable base platform.
[update] Since I've got the new extruder and new firmware now, I did a factory reset and recalibrated. MMU2 power/signal cables disconnected, idler open, just feeding filament from the back through the MMU2 selector/PTFE. Seems to work fine as a normal MK3.
Calibration and PLA print went fine. Did a PID calibration and then printed a black PETG calibration cube.
I'm now printing a new idler in black PETG, 3 perimeters/40% grid infill. I think recommended is 2 perimeters/20% infill, so I'm sure I'm going to regret my paranoid overkill when it turns out the recommendations were there for a reason.
I had to get medieval on the original idler to get the hardware back:
The real question I need to figure out before I reassemble: what did I do wrong that caused the original idler to self destruct?
Re: Idler broke while loading filament for the first time
I can't say 4 certain why yours broke on your 1st print.
But I can say mine looked exactly like your photo after I over torqued the screws that attached the idler body to driver shaft.....
Luckily had another mk3, just printed another one. Was a pain getting the hardware out.
Prusa MK3 preassembled (R2/B6) > (R3/B/7)
Prusa MK2.5 kit > MK3 > MK3+MMU2 (R3/B/7) 😀
Prusa SL1 3D printer + Curing and Washing Machine (day1 order)
Taz6
CR10s4
Delta 3ku
Re: Idler broke while loading filament for the first time
I can't say 4 certain why yours broke on your 1st print.
But I can say mine looked exactly like your photo after I over torqued the screws that attached the idler body to driver shaft.....
Luckily had another mk3, just printed another one. Was a pain getting the hardware out.
Quite possible I overtorqued. I am usually pretty good on 'monkey strong' not 'gorilla strong', but who knows, it was late at night. Even if I didn't crack it, I could have weakened it and it cracked later.
I've already printed a new one, as even the MMU2 Mk3 works just fine as a plain mk3 if you just unplug the MMU2 wires. My only delay was that I'd rebuilt the extruder and needed to go through calibration. Looking good so far. 3 perimeters, 40%, so slightly sturdier.
