Filament stuck after a few hours
Hi,
the (usual?) problem: after a few hours of printing, the filament gets stuck somewhere in the extruder, and the next morning, the machine is printing with nothing on thin air. Happened twice in a row to me now after converting from the i3 Mk3 to the Mk3S/MMU2S, so may be related to that conversion, but probably not to the MMU. In both cases after about the same time (may have been one layer sooner or later, but not more).
This is what the end of the filament looked like this morning. I had a print running over night, which worked fine for the first few hours. This morning, the printer was still running, but the head was moving in thin air above the already printed part. No stringing or anything. When I stopped the print, the MMU was able to retract the filament (pushing back to the spool), but got stuck at the final part, i.e. the tip of the filament was wedged inside the MMU in the short tube between the selector and the idler gears.
It was a single material print, so no filament changes involved. Filament is the Prusa silver grey test spool that originally came with the printer.
Re: Filament stuck after a few hours
sounds like it could be related to the PTFE tube inside the extruder.
did you swap it out when doing the upgrade like the instructions say?
Re: Filament stuck after a few hours
Hi,
the (usual?) problem: after a few hours of printing, the filament gets stuck somewhere in the extruder, and the next morning, the machine is printing with nothing on thin air. Happened twice in a row to me now after converting from the i3 Mk3 to the Mk3S/MMU2S, so may be related to that conversion, but probably not to the MMU.
I agree that it's probably not the MMU itself.
Have you ruled out the Usual Suspects for a filament jam? I would check for a nozzle clog, check the tension on the Bondtech gears (neither too tight nor too loose), etc.
Re: Filament stuck after a few hours
sounds like it could be related to the PTFE tube inside the extruder.
did you swap it out when doing the upgrade like the instructions say?
Sure - didn't even think the old one would fit.
I agree that it's probably not the MMU itself.
Have you ruled out the Usual Suspects for a filament jam? I would check for a nozzle clog, check the tension on the Bondtech gears (neither too tight nor too loose), etc.
Checked both - did a cold pull the first time that happened, and removed and reattached the door a few times (no other way to access the gears 😕 ). Have been printing all day long today with shorter (up to 5 hours) PETG jobs, including my first dual filament print, and all was fine.
My current guess is that it may be correlated to the temperature - I have the printer in a closed box, and even though I haven't installed the door seal yet, it gets pretty warm inside if I shut the door. I'll repeat the offending print (same filament, but only half the components on the platter, so I don't have to run it over night) in the next couple of days with the box left open and see what happens then. If that works out, I'll have to finally assemble and program that fan controller.
Re: Filament stuck after a few hours
Ok - it probably was a combination of the (age, storage) filament and the heat in the box. Right now, I tried to load a different filament into the channel I had previously used. So far, I have fished three fragments (~1 cm each) out of the MMU that were blocking the path at one place or another.
Re: Filament stuck after a few hours
My current guess is that it may be correlated to the temperature - I have the printer in a closed box, and even though I haven't installed the door seal yet, it gets pretty warm inside if I shut the door. I'll repeat the offending print (same filament, but only half the components on the platter, so I don't have to run it over night) in the next couple of days with the box left open and see what happens then. If that works out, I'll have to finally assemble and program that fan controller.
I've heard that PETG tends to jam if you print it in an enclosure, so that makes sense to me.
Enclosures are most useful for printing ABS. Unless you're printing ABS, there's probably little to no benefit in using an enclosure.
Re: Filament stuck after a few hours
I've heard that PETG tends to jam if you print it in an enclosure, so that makes sense to me.
Enclosures are most useful for printing ABS. Unless you're printing ABS, there's probably little to no benefit in using an enclosure.
Two benefits:
keep out the dust and cat hair
keep in the noise from the printer