PETG filament completely immobilized/stuck in extruder
During a print I noticed that the month-old fully assembled Core One+ I received was making a loud clicking noise coming from the extruder, so I stopped the print. Upon further investigation, the PETG filament loaded into it was completely stuck in place, unable to be pushed in or pulled out, even when the nozzle was heated to 290C. I’d opened the idler latch and I think I see a strip of filament down the middle of it, but it’s impossible for me to get a good angle to see it. Attempting to remove the nozzle using the provided wrenches was unsuccessful, it was coming off at first but then it got stuck and wouldn’t turn further. I went through the article about the cold pulls and then found the article about stuck filament, but there doesn’t seem to be an explanation of how to address this problem since I cannot load or unload the filament. Since I decided to purchase the pre-built model, I’m apparently rather ignorant on how to properly service it.
If this is a duplicative post, please point me in the right direction as I’ve been struggling to find the proper place to ask for help.
RE: PETG filament completely immobilized/stuck in extruder
When you were removing the nozzle, did you loosen the two thumbscrews? Also, it most likely your nozzle is clogged. What kind of nozzle is it?
RE: PETG filament completely immobilized/stuck in extruder
Exactly the same happened to me in the first week (user error: printing temperature was too far off).
My solution, take the Nextruder apart and clean the base plate (the PETG was sticking quite solidly to it, this took some time). Then, and here comes the potentially hard part (unless you built the kit) - put it back together. You'll need a 3D-printed tool for gear alignment, don't try without it.
If you place an order, order a new base plate, the Nextruder assembly tool and potentially a spare nozzle (I'm confident you can recover it by drilling out the top with a 2mm drill and cleaning the bottom end via cold pull but one problem at a time...)
RE: PETG filament completely immobilized/stuck in extruder
The stock one that came with the printer, and no, I did not loosen the thumbscrews. I ended up re-tightening the nozzle back into its original position. Somehow, I managed to get it working again just a few minutes ago by doing the following:
1) Unscrewing the PTFE tube from the top of the extruder, exposing the stuck filament and then cutting it using the pliers that came with the kit at about an inch up from where it entered the extruder.
2) Opening the idler latch and getting more light on what's inside so I could see the roughed-up looking filament running vertically across the silver gears.
3) Used the pliers to very carefully get a grip on the filament and pulled gently at first, finding it was stuck firmly in place.
4) Using the pliers, I pulled the filament away from the gears with what I think is a moderate amount of force and found it gave slightly, creating a small bent loop of filament.
5) Pulling a bit harder, I was able to snap the filament loop and then with a fair bit of force extracted the top section of the filament through the gears out the side of the idler.
6) Seeing that the portion of the filament loop leading down towards the nozzle had snapped close to the gears, I left that alone.
7) I closed the idler latch and then re-secured the PTFE tube to the top, hand-tightened only.
8) On the front interface I ran the following steps, but do not know if all were necessary: purge, unload filament, load new filament.
9) At that point there was a soft whirring noise as it loaded the new filament (still PETG) and extruded a string of PETG filament, about maybe 2' (60cm) of very thin filament.
10) From there, it seemed to be operational when printing a small model.
RE: PETG filament completely immobilized/stuck in extruder
Thank you for responding, I was able to get it fixed using the steps described in my other response. It seems like the nozzle itself was fine, but there was something jammed up in the silver gears at top, which I think are part of the Nextruder assembly you've described.
I feel there is a catch-22 in needing the 3D-printed tool to fix a 3D printer which won't print, seeing as there's no way to print the tool. It would be nice if such a tool were included along with the other supplies that came with the printer. I will definitely be printing one of those now though!
RE:
... catch-22 ...
Always wear flak jacket when ordered. It prevents shrapnel from passing through.
And watch more Prusa marketing videos. Ever seen J.P. require a Nextruder assembly tool?
'Nuff said.
RE: PETG filament completely immobilized/stuck in extruder
The stock one that came with the printer, and no, I did not loosen the thumbscrews. I ended up re-tightening the nozzle back into its original position.
Never try to unscrew the nozzle without first sufficiently loosening the two thumbscrews. Failure to do so can damage both the nozzle, possibly the screws and heatsink threads. The screws secure the nozzle to the heatsink via two indentations in the nozzle heat break tube.
RE:
I feel there is a catch-22 in needing the 3D-printed tool to fix a 3D printer which won't print, seeing as there's no way to print the tool. It would be nice if such a tool were included along with the other supplies that came with the printer. I will definitely be printing one of those now though!
This part can also be ordered from Prusa. The reason it's not included is that there should generally be no need to disassemble the Nextruder planetary gears.
Pro tip, pick up a spool of Prusament PC-CF and print all of the Nextruder parts to keep around as spares. Especially the fan shroud.
It's not a Catch 22 because you can always buy the parts from Prusa or Printed Solid if need be. With other printer manufactures you don't even have the luxury of being able to print spares.
RE: PETG filament completely immobilized/stuck in extruder
I haven't really seen many Prusa marketing videos, so I don't know anything about how things are done with or without such a tool. The main concern I've been having with ordering new parts/tools is I've been very confused as to which parts I may or may not need, or when exactly I should replace a part. The Prusa support link has been very difficult to find on the site and when I clicked the button for support chat, it didn't work at all. Many of the documentation links scattered about seem to go to older versions of the documentation.
Coming from previously learning on the Bambu A1, I was hopeful that purchasing the assembled Core One would make setup a relatively straightforward process. I'd heard good things about it from online reviews. I've been slowly coming to understand that there is a much greater expectation that users of the Core One be familiar with the ins-and-outs of 3D printing and the Prusa ecosystem.
I'm not especially enthusiastic about the notion that I'll have to print/buy replacement printer parts in the near future given the cost and difficulty of obtaining the printer, plus the long shipping times and occasionally notices that things are on backorder. However, the advice is appreciated and I'll have to spend more time browsing the Prusa online store.
RE: PETG filament completely immobilized/stuck in extruder
Following up on the suggestion to purchase Prusament PC-CF, I'm assuming that refers to: "Prusament PC Blend Carbon Fiber Black 800g (NFC)". If so, and given the warnings in the description for the product, do I need to purchase a different nozzle as well or is the one that ships with the Core One appropriate to use for printing the parts?