Filament stuck in PTFE tube - won't extrude or unload
 

Filament stuck in PTFE tube - won't extrude or unload  

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wook
 wook
(@wook)
Active Member

So after nearly a month of trouble free printing I've had my first major issue.  The print was almost finished - I didn't see it happen but from what I can tell the filament quit feeding.  There were no reported errors on the printer. I tried to test print and then unload the filament.  Neither worked and there is a clicking/grinding noise.

 

[img] [/img]

 

I looked it up and it appears to be a clogged nozzle or hot end.  The nozzle is clogged (I checked with a pin) but heating it up doesn't seem to help.  I tried to manually unload the filament with no luck.  I am using this guide:

https://help.prusa3d.com/en/article/clogged-hotend_2008/

I'm at the stage where I have the hotend removed from the extruder assembly and I've tried heating it up to pull the filament out with pliers but it won't budge.  I'm not sure what to do next.  I don't want to damage the PTFE tube. 

 

[img] [/img]

 

I have had this printer for a month - I don't think I should have to be buying new parts already. 🤨 

 

Posted : 30/05/2020 4:11 pm
Andrew
(@andrewld)
Estimable Member

I got my PLA out by over heating the hot end (225) and used pliers to push and pull the filament from close to the entry hole. The effort required was borderline excessive but done gently in very small increments. Once I felt I had some play I opened the idler gear flap so I had a good view of the top of the PTFE tube. I set the temp to cool down and did a cold pull. This worked and after a good flush through with another filament all appears well......so I will count myself lucky. Fingers crossed on your behalf.

Andrew

Posted : 31/05/2020 10:07 am
d.boath
(@d-boath)
Active Member

I've experienced this also some time back. It happens. But once you've got to the stage in your photo, then next time will be a breeze. 🤣 It's just daunting taking it apart the first time. I tried cold pulling and it snapped... right flush with the ptfe tube. 🙄 

I would use a pair of side cutters and cut that filament off about 2cm above the white PTFE tube. Pull  the rest of the filament back up and out of the whole assembly.

Now with your hotend, push the small black ring around the ptfe tube and using pliers, grab filament and pull. It should bring the ptfe with it. Make sure you are pushing down on the ring while pulling.

There should be a spare ptfe tube that came in a bag with the printer (I purchased the kit, so it had a spare. Not sure if pre-assembled does). If not, you could try heating up the tube with the filament via a heat gun or hair dryer. Try not to crush the ptfe tube, but I would try and pull the filament out. Try not to overheat the tube either. Any warping will be bad/not a clear run. Which is why it's better to simply replace. You might be lucky and once the tube is out of the hotend, the filament may come out.

Reinstall tube once clear, or with a new one. Make sure you pull the little black ring up once the height is set (I have it sit just below the feed in gear, but follow your picture for a rough height of how much is sticking out). Also make sure you have the new tube the correct way.

Guide is here: https://help.prusa3d.com/en/guide/how-to-replace-ptfe-tube-on-the-mk3s-mk2-5s-mmu2s_21664/

Reinstall hot end. Before you get carried away feeding new filament in, I would heat it up to 250 degrees and using a small needle or (widely available off ebay), nozzle 'acupuncture' style needles to make sure you can run it all the way up through nozzle and out the top of the PTFE tube. If you can do that, let it sit at 250 for a few minutes. Then select Load Filament from menu. Hopefully it pushes through smoothly. 😉

Posted : 31/05/2020 2:07 pm
wook
 wook
(@wook)
Active Member
Posted by: @andrewld

I got my PLA out by over heating the hot end (225) and used pliers to push and pull the filament from close to the entry hole. The effort required was borderline excessive but done gently in very small increments. Once I felt I had some play I opened the idler gear flap so I had a good view of the top of the PTFE tube. I set the temp to cool down and did a cold pull. This worked and after a good flush through with another filament all appears well......so I will count myself lucky. Fingers crossed on your behalf.

Andrew

Thanks.  Tried this.  as I was trying to get a little play in the filament, it broke off at the entry hole.  I wasn't even using much force at this point - I was surprised how easy the filament snapped (Prusament PLA).  Once the nozzle cools off I'll try it again with the hot end extracted.  I've heard nothing back from Prusa email support and I haven't had a chance to sit at my computer for the half an hour to get chat support.  The honeymoon is over.

Posted : 31/05/2020 2:50 pm
wook
 wook
(@wook)
Active Member

Well, the cold pull resulted in the filament breaking off in the tube. Got the tube out of the hot end. The filament is now stuck in the tube, and my nozzle is still clogged.

 

Posted : 31/05/2020 3:27 pm
Karl Herbert
(@karl-herbert)
Famed Member

@wook

You can add a little more heat to the hotend, about 230 degrees and first try to help with a nozzle needle or remove the nozzle and use a 1.5mm copper wire. Pretty sure you have a thickened tip, which is stuck in the heatbreak or PTFE. Before you use force, you should cut the filament above the PTFE and try to disassemble the hotend step by step. The prusa spare part assortment should include a PTFE tube. I would buy some of this material as a replacement: https://www.captubes.com/

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 31/05/2020 3:39 pm
charles.h13
(@charles-h13)
Famed Member

I use 1mm and 1.6mm tungsten rods.  It has worked well to push jams through.  

1mm tungsten rod

1.6mm Tungsten Rod

 

 

Posted : 31/05/2020 4:56 pm
Karl Herbert
(@karl-herbert)
Famed Member

@charles-h13

Tungsten - very good idea, thanks. Just ordered these electrodes too.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 31/05/2020 5:42 pm
easigoodz
(@easigoodz)
New Member

i had this issue, i removed the nozzle and used a long 1.5mm Allan key to push it out backwards. worked well as i tried everything to push it thro the hot end and extrude out but for some reason a part of the pls just did not want to melt and go thro.

Posted : 01/06/2020 2:22 pm
Karl Herbert
(@karl-herbert)
Famed Member

@easigoodz

Sometimes it can be necessary to disassemble the hotend. Do not apply high force under any circumstances.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 01/06/2020 4:37 pm
wook
 wook
(@wook)
Active Member

@d-boath

thanks!  That is what I pretty much ended up doing. I couldn’t get the filament out of the tube, so I suspect the tube had sustained some kind of damage. Luckily, I have a kit and it came with two extra tubes so I was able to replace it. Back in business... well, back in business once I re-adjusted my extruder gear which seemed to have gotten knocked out of whack a little bit during the disassembly process. 

clearing the nozzle was a snap once I was able to manually push filament through the hot end . Support walked me through it.  

The filament did break off flush with the tube for me as well. It was really stuck in there, once it was all disassembled I was able to extract the filament from the tube but had to use considerable force. So that tube is garbage. 

I was printing 0.05mm with a 0.4 nozzle and using the galaxy line of Prusament filament. Support advised against that. So I’ll stick to 0.1mm for my detailed prints and phase out the glittery filament (which I only bought because the regular was out of stock). 

thanks everyone for your input. I appreciate it. This stuff is daunting and frustrating when first introduced to it. There is a steep learning curve but all very manageable in hindsight.  A couple pints of Guinness helped to. 😀 

Posted : 01/06/2020 5:06 pm
charles.h13
(@charles-h13)
Famed Member

I try to push the filament gently with a headed hot end.  If it will not budge, I remove the PTFE tubing use a heat gun to try to loosen it while pushing the filament.  

Posted : 01/06/2020 6:19 pm
wayne.h-1
(@wayne-h-1)
New Member

I hd the same problems... after cleaning out the 4th clog in maybe 15 minutes of print time, I concluded it must be the filament.

So while the filament is baking in the oven at 50c, I decided to under my hotend and clean it all up..  I took it apart, cleaned up the nozzle and heat exchanger .. set my temperature to 280 to put the nozzle back into the block and it twisted off with about 1.5 threads left outside the block...

 

So now I am hosed!

Posted : 02/06/2020 8:02 pm
leonardo.lacchini
(@leonardo-lacchini)
New Member

 

I have had this printer for a month - I don't think I should have to be buying new parts already. 🤨 

 

Same here, one mouth mk3s, printed 2 times prusa logo to check first layer

when  print benchy, after 2h the extruder sound like "clack", i cleaned the hotend and restart, after 1h same problem

 

Posted : 03/06/2020 1:37 pm
d.boath
(@d-boath)
Active Member

@wook

Hey glad to hear you have it sorted. 😁 Make sure you do a first layer calibration again and live Z adjustment just to really dial it in.

I could go a guinness actually....

Posted : 03/06/2020 11:07 pm
charles.h13
(@charles-h13)
Famed Member
Posted by: @charles-h13

I use 1mm and 1.6mm tungsten rods.  It has worked well to push jams through.  

1mm tungsten rod

1.6mm Tungsten Rod

I ordered another set.  These things work very well at clearing clogs.  

Posted : 08/06/2020 11:40 am
wayne.h-1 and jsw liked
Karl Herbert
(@karl-herbert)
Famed Member

@charles-h13

I now also use tungsten carbide rods 1, 1.6, 2 and 2.4mm (a cheap set). They are just right in diameter and length to remove blockages.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/06/2020 7:42 pm
charles.h13
(@charles-h13)
Famed Member

@karl-herbert

Posted by: @charles-h13

I use 1mm and 1.6mm tungsten rods.  It has worked well to push jams through.  

1mm tungsten rod

1.6mm Tungsten Rod

 

 

I use 1mm and 1.6mm as listed above.

Posted : 08/06/2020 8:41 pm
Karl Herbert
(@karl-herbert)
Famed Member

@charles-h13

very good material!

for buyers in europe:

set 1.6, 2, 2.4 mm

1 mm

 

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/06/2020 10:13 pm
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