Clogged Extruder and broken filament? - General discussion, announcements and releases

RE: Clogged Extruder and broken filament?

Garrett Cannon — Mon, 21 Aug 2023 20:30:19 +0000

My MK4 is also having problems. I got halfway through a 8hr print when filament just stopped coming out. I tried to purge but the gears just kept slipping along the filament and did the same thing when trying to unload. I had to open the side to relieve some pressure and then use pliers to pull it up and out. It morphed a bit from the gears trying to push it down and made it a bit fatter where it was broke. I got a couple smaller prints out of it before it happened again. Except this time whatever is stuck is further past the gears. I tried heating the nozzle and sticking the acupuncture needle up it and that didn’t do anything. If I try to load filament and purge then the gears just slip along the filament again. I have no idea what to do.

RE: Clogged Extruder and broken filament?

Rince — Sun, 13 Aug 2023 20:31:51 +0000

Just a heads-up: I have now extracted the tube and used an air-heater to make the broken filament fluid; this worked then to get the broken filament out. Now, apparently some filament is stuck in the gear and I will remove it as good as possible ;)

I have no idea why Prusa switched from the ptfe-tube to a metal-tube all the way, but I would have preferred to be able to "split" the tube to make cleaning easier... ;)

(especially since you can not order yet the tube as replacement part at prusa ...)

best regards, Hanno

RE: Clogged Extruder and broken filament?

heinzv — Mon, 07 Aug 2023 17:39:34 +0000

I have exactly the same problem with my brandnew MK4 with any 5 print with a brandnew Prusament.
It start printing in the middle or at the end with no more filament extrusion and I found out, that it always breaks in the hotend or at the top of the hotende.
Also the extroder starts with a loud cracking sound.
I managed to get the filament out at 280 degree with a loong 0.4mm needle (meant for such puposes) but after the thrird break, I can't get the filament out, it's stuck in the middle of the hotend and does not move in any direction.
Seem to be a problem with the MK4 or Prusa shipped faulty filament with the MK4. It is brandnew and storeed in the enclosure and I just started to use it.
Let me know if you could solve it and what the root cause was.
If I cant get it solved with a new hotende and new filament, I need to send the MK4 back.

Posted by: @rince
Hi,

I used some old PLA-filament to print the first parts of the upgrade of my (old) MK3 to MK4. after a while I saw that the printer was not printing anymore - no filament was put out.
looking to the nozzle (and taken it out of the extruder box) I saw that the filament was broken. I heated up the heater to 280°C and first tested with an acupuncture needle wether the nozzle is free - and it seems to be. But I wasn't able to take the filament out from above since there was no way to fetch it. then I tried to push it down with an inbus key but it wasn't able to push the filament (it stopped after ~1cm).
since currently I can not order a new nozzle from Prusa, what are my options? are there longer needles I can use to find the blocked part from down below and "push" it upwards? can/shall I move the heaterblock and hope that I can make the filament more fluid inide the tube?

Diem — Tue, 01 Aug 2023 22:51:19 +0000

Heat the nozzle and remove it - see the nozzle change procedure.

You should be able to push the residual filament through the wider path with another piece of filament, follow up with a cold pull.

Inspect the nozzle and decide whether to reinstall or replace it - then complete the change procedure and try again.

Brittle PLA is a symptom of water takeup - if left out in humid conditions for a long time it micro-cracks and can, sometimes, become unuseable but first try drying it and you may be able to restore it.

Cheerio,

RE:

haxxlinus — Tue, 01 Aug 2023 12:20:45 +0000

Head to the nearest music store and buy a guitar string to use instead of the acupuncture needle.

Clogged Extruder and broken filament?

Rince — Tue, 01 Aug 2023 10:15:57 +0000

Hi,

I used some old PLA-filament to print the first parts of the upgrade of my (old) MK3 to MK4. after a while I saw that the printer was not printing anymore - no filament was put out.

looking to the nozzle (and taken it out of the extruder box) I saw that the filament was broken. I heated up the heater to 280°C and first tested with an acupuncture needle wether the nozzle is free - and it seems to be. But I wasn't able to take the filament out from above since there was no way to fetch it. then I tried to push it down with an inbus key but it wasn't able to push the filament (it stopped after ~1cm).

since currently I can not order a new nozzle from Prusa, what are my options? are there longer needles I can use to find the blocked part from down below and "push" it upwards? can/shall I move the heaterblock and hope that I can make the filament more fluid inide the tube?