Filament stuck on top of PTFE  

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Zorro_X
(@zorro_x)
Active Member

Hi, 

I was printing with PET-G (octofiber) then the nozzle has clogged (for the first time, there is not a moth since I've received it neither 20 hours of printing). I tried to remove the PETG filament but i heard a "clack" on the top of the extruder and the filament was "broken" (not melted as usual), then impossible to insert any new filament... The PETG seems to have melted on the top of the PTFE entry and I'm unable to do anything, I've even tried to push it with one of the little hallen keys provided but there is nothing to do : nothing moves. (see joined image)

From the other side I'm able to insert the accupuncture unclogging device but nothing else...

Now I don't know what to do... 🙁

 

Posted : 17/11/2020 2:58 pm
Tim
 Tim
(@tim-2)
Illustrious Member

To clear that type of jam, just heat the hot end up to 10c over the normal print temp, and start inserting new filament. You can usually push the new filament down and it will push the old filament along. If filament won't allow you to push hard enough, a length of copper wire (house wire) or even a long Allen wrench will also work.

It is always wise to get more than one opinion...
Posted : 17/11/2020 10:18 pm
Zorro_X
(@zorro_x)
Active Member

@tim-m30

hi, thankyou, I've got near the same tip from another forum : I've finally used a copper wire of 1.5mm² heated before putting it into the PTFE by the side (previously opened) to avoid melting the filament detector and other parts, then once 1-2mm of stuck filament removed from the PTFE I was able to insert a new filament by pushing it by hand and everything goes well since...

For the record, it seems the PET-G filament has somehow melted in the PTFE making it a bit larger and it was not able to continue forward neither backward (I've already had that problem on other printers). This problem is usually linked to a too long retraction distance, but in my case the retraction was set to 0.8mm so I don't know where it may have came from... or maybe octofiber PETG is not really compatible with prusa printers (?).

Posted : 18/11/2020 10:54 am
Tim
 Tim
(@tim-2)
Illustrious Member

Using a hot wire is a mistake. Just use a plain old cold copper wire to push with. You do not want to melt plastic in the upper heat break, that will just make a mess you'll need to tear down to fix.

It is always wise to get more than one opinion...
Posted : 18/11/2020 4:28 pm
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