Filament stuck  

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kronoss
(@kronoss)
New Member

Hi, today i came to our printer and it was stuck - filament somehow stuck and broke in level of entry into nozzle (in the picture) i tried to heat up the extruder and push it through from the top with another filament, but no luck. Could you anybody give me tip how to remove that without disassembly whole "printer head" ? Thanks

Posted : 24/07/2019 10:00 am
Protoncek
(@protoncek)
Reputable Member

You can't. Been there, done that. Several times. Reason? Hot environment, PLA and printing part which requires frequent reverse movements of filament with very short forward movement. Filament in this case flows very slow and since motor (and with it gears, too) is (too) hot gears consequently heat up PLA beyond the point where it becomes soft.

Long term solution is an additional fan which cools down extruder motor (or at least passive alluminium cooler). Or ,some guys installed small fan which blows through extruder gears.

Posted : 24/07/2019 11:13 am
kronoss
(@kronoss)
New Member

Thanks for reply! So what I need to do now is disassemble whole "printer head" ( practicaly reverse assembly by manual: https://manual.prusa3d.com/Guide/5.+Sestaven%C3%AD+osy+E+(extruder)/1082?lang=en )? 

Is it true, that we put printer into LACK enclosure, so your theory is very possible. In this case, for long using printer in enclosure you recommending something like this: https://www.thingiverse.com/thing:2975582 ?

Posted : 24/07/2019 11:59 am
lindharin
(@lindharin)
Eminent Member

I've never had luck trying to clear it by using another piece of filament; it just tends to be too flexible and slippery to work well for me.  Here are the steps I've tried.

Heat the nozzle, then use a small needle (did one come with the printer?  I don't recall. I also bought some from amazon) to stick up through the nozzle entry.  I let it heat a little from the nozzle then exerted a little pressure up into the clog.  If the clog is at the tip of the stuck filament, this might loosen it even if it is just above the hot zone.  If it starts drawing out some filament, then I tried feeding filament through the extruder, assuming it is either still loaded or there is enough room at the top of the PTFE tube that new filament can be loaded into it above the stuck filament.  

If the needle doesn't work, or I can't easily exert pressure on the stuck filament to see if the needle worked, then my next step is to use a brass rod (I think 1.5mm diameter is recommended, preferably with a rounded tip) and feed it into the filament hole from the top and try to push the stuck filament down into the hot zone.  I start by heating up the hot end, loosen the tension screw holding the extruder idler and open the idler door, and insert the brass rod down through the filament hole and into the top of the PTFE tube, and see if I can push the stuck filament down into the hot zone.  

If that fails, the next thing I've done is removed the nozzle, and stick the brass rod up into the heat break and see if I can push the stuck filament up and out of the PTFE tube, at least enough to be able to grab the top of it with needlenose pliers.  At that point I can either pull it out through the idler door (that's rare, usually doesn't bend easily enough) or more likely push it up a few mm and snip off the exposed part, then push up a few more mm, snip that off, repeat until it is all out of the PTFE tube. 

If that fails, then I've done the partial disassembly (steps 3-5 of the PTFE tube replacement process) to pull out the hot end and take a closer look.   The partial disassembly is actually really pretty simple, as long as you are careful about the hot end wires and orientation when reassembling. The only time I really needed to do this, my filament was stuck inside the PTFE tube itself and was tight enough that I couldn't push it through in either direction.  I was able to just release the collet holding the tube in place and pull it out and replace it.  I had a spare PTFE tube so I just replaced it, but I still have the original tube with the stuck filament since I've seen references to getting the filament out by softening it in boiling water, but haven't tried it yet.  

Posted : 24/07/2019 1:54 pm
bobstro liked
Tim
(@tim-m30)
Illustrious Member

A wild idea I've always said I'd try if this happened to me:

Heat the hot end to 280c; remove the nozzle. Let things cool a bit, then push from above with a long 1.5 mm Allen key or stiff wire.

This way there's not 0.4 mm orifice to get through, it's mostly 2.0 mm except for that silly 2.2 mm step Prusa has E3D add to the heat break.

If the filament doesn't come out using this method, it's almost proof the heat break is causing the jam in the first place.

 

It is always wise to get more than one opinion......
Posted : 24/07/2019 3:25 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: Tim

[...] Heat the hot end to 280c; remove the nozzle. Let things cool a bit, then push from above with a long 1.5 mm Allen key or stiff wire.

This way there's not 0.4 mm orifice to get through, it's mostly 2.0 mm except for that silly 2.2 mm step Prusa has E3D add to the heat break.

If the filament doesn't come out using this method, it's almost proof the heat break is causing the jam in the first place.

I usually try it at normal print temp first but crank it to 285C if that fails. You can also push from below, which is sometimes better I think as you're not forcing more crud down into the hotend.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 24/07/2019 3:29 pm
kronoss
(@kronoss)
New Member

Huge thanks for all tips. After all I had to half-dissassembly "printer head" and remove filament alongside with PTFE tube.
Another experience for me 🙂

Posted : 25/07/2019 3:24 pm
Tim
(@tim-m30)
Illustrious Member

If your PTFE was deformed, PLEASE, post a photo of it.

It is always wise to get more than one opinion......
Posted : 25/07/2019 7:53 pm
kronoss
(@kronoss)
New Member

After all it was probably just stuck on the enter to that tube. So next time i will need thin needle to stick out filament from underside through nozzle.

Posted : 26/07/2019 11:56 am
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