cant load filament. Hard time troubleshooting
I have a MK3s+MMU2s
sorry for the verbosity here, I hope it saves steps of "Did you try..."
The MMU2 definitely complicates things, constantly trying to load and unload the filament, even if I get it extruding it unloads it for a print and fails to load.
I was printing well. I've probably printed 10kg on this printer. It was super reliable before the MMU2s, since then I've got used to a few of the common MMU2 loading issues.
I decided to do a very long print and wasnt sure if I had enough PLA for it. I didn't It probably ran 6 hours without filament. It failed to detect the no filament cuz the last bit of it didnt make it into the MMU PTFE feeding tube.
I havent been able to print since then.
It takes some effort but I can push filament through the extruder al the way to the hot end, but not to the point where it extrudes.
I took the extruder apart. the nozzle is clean I can push filament through it but it IS tough to push filament through the PTFE tube. I pushed an allen wrench into the PTFE tube to widen it slightly and that seemed to help, I can push filament through it pretty easily. I put the nozzle back on, was sure not to overtighten and can push the filement through the tube and nozzle and watch it extrude. When I reassemble the whole extruder it's much harder to push it through, but I can do it by hand. then the MMU retracts it all tries to load and fails.
I've repeated the aove many times, trying to trim the filament just right, adjust extruder idler tension, partially assembling etc.
I just ordered some new PTFE tubes, hoping that's the problem but I'm not sure since I CAN push filemant through the PTFE tube
hoping to get printing again soon. I have projects!
If it makes sense to bypass the MMU2s somehow I'm willing to do that too
Best Answer by anthony.a4:
it can be a little misleading but the problem was my IR sensor not detecting the filament in the extruder.
When it failed to detect it it thought it was a mmu problem.
I figured this out by:
- Disconnecting power to MMU2s
- Going to Support->Sensor info
- forcing filament into the extruder and watching the sensor info. it would flicker between 0-1 when filament was in.
So I checked connections and barely tweaked the sensor assembly in relation to the extruder body and it seems to have fixed it.
changing the PTFE tube im sure didnt hurt but it wasnt by issue.
RE: cant load filament. Hard time troubleshooting
Pick up some cleaning filament and do a cold pull. Or two.
Sure sounds like something caked up in the hot end area.
On your new tubes - test the bore with a filament scrap before cutting. Make sure it slides freely.
Some PTFE tubes have the bore neither centered nor big enough. Lots of trash out there.
Side note: Is it possible to drill out PTFE the correct size?
RE: cant load filament. Hard time troubleshooting
@robert-rmm200
I can push filamant through nozzle easily without the ptfe tube. it also looks pretty clean inside
I bought my ptfe tubes precut for my printer from prusa site. I assume thi swill avoid all the issues you mention or require boring
RE: cant load filament. Hard time troubleshooting
Never hurts to slide a bit of filament through a Prusa tube before assembly.
We like to think Prusa is extra careful, but I did see one report of a tight tube from them.
Also - some filament just comes too big. Sticking in the tube - is bad.
[SOLVED] RE: cant load filament. Hard time troubleshooting
it can be a little misleading but the problem was my IR sensor not detecting the filament in the extruder.
When it failed to detect it it thought it was a mmu problem.
I figured this out by:
- Disconnecting power to MMU2s
- Going to Support->Sensor info
- forcing filament into the extruder and watching the sensor info. it would flicker between 0-1 when filament was in.
So I checked connections and barely tweaked the sensor assembly in relation to the extruder body and it seems to have fixed it.
changing the PTFE tube im sure didnt hurt but it wasnt by issue.