Stuck Fillament!

[smorgana 0]

I have an Ultimaker 2 that I upgraded to a 2+ years ago... it has been working beautifully...

 

Today I had a print that failed because the filament stopped feeding...    There is any of a number of reasons why the filament stopped, but, as it does, the extruder chewed a notch in to the filament...   I managed to get it out running the filament change program, and pulling to get past the notch..

 

The spool looked fine, not tangled, rotating freely so I thought Ok, just try again..

 

The second time the filament got stuck again...   Now there is no budging it...   I took the extruder apart thinking there was a jam in there.. no.. I have it free of the extruder now..   It appears the problem is at the printhead end.   Even though I have it heat the nozzle up to 210 (it's pla filament) As much as I pull I can not get the filament out at the printhead end.

I know it is not bound up in the bowden tube because I can see the filament flex in it as I push and pull.   The nozzle is darn hot... so I know that much is working... but it is just stuck..

 

What should I try next?  Am I going to have to take the printhead apart?

 

Another symptom... I can't get the bowden tube out at either end.   As you all know there is a blue clip... I removed those.  Then you push down on the white collar and pull the tube out...   Well that doesnt work at either end... the whole collar and tube is free at the extruder end... the  bowden tube at that end  has like a slice around the tube.. the collar wont move past that slice to get free of the tube.    I assume the same thing is going on at the printhead end.. push down on the collar, pull up on the tube.. it comes up about an inch and gets stuck..   even with stuck filament I should be able to free the bowden tube at the printhead end considering it is already free at the extruder end.

Edited September 18, 2020 by smorgana

[smorgana 0]

I had more time to dig in to it.   I loosened the 4 long screws to drop the head down to see what was going on.

 

the filament is in fact stuck in the head end of the boden tube.

 

the filament had developed a ring around it just outside the top end of the print head tube.  Probably due to a clogged nozzle. as the filament was softened and te extruder pushed agains the clogged nozzle it created a ring.

 

 that ring is just a bit to big to pull through the bowden tube..   when I originally tried to extract, I pulled as the extruder was reversing... that logged the filament in the bowden tube..   That's also why  I could not pull the bowden tube out the printhead end.. it was expanded by the ring on the stuck filament.

 

Its real stuck in there with nothing showing at the printhead end to grab to pull it out...   so I'll probably just get a new bowden tube.

 

Also I'll put the printhead back together and get the nozzle off to see if it needs cleaning.. or a new nozzle

 

[Carla_Birch 116]

I would check the front cooling fan is spinning and working right if the filament had grown a ring around it outside of the print core, as you might have had heat creep due to front fan not working/spinning free.

[smorgana 0]

On 9/19/2020 at 12:58 PM, Carla_Birch said:

I would check the front cooling fan is spinning and working right if the filament had grown a ring around it outside of the print core, as you might have had heat creep due to front fan not working/spinning free.

Wow!  That was it.

 

I put on a new bowden tube because I could not figure out how to get the jammed filament out of the old one.  Also bought a new nozzle just in case.

I went to do the atomic method to clear the old nozzle before taking it out, and realized the printer was silent.  The top fan on the printhead was not spinning.. I gave it a push and it started spinning.

 

So right now it will spin if I turn the printer of and on.. but it's not sounding like a good spinning fan.

 

 

ah...  something is impeding the fan...   

Edited September 25, 2020 by smorgana

[Carla_Birch 116]

9 hours ago, smorgana said:

Wow!  That was it.

 

I put on a new bowden tube because I could not figure out how to get the jammed filament out of the old one.  Also bought a new nozzle just in case.

I went to do the atomic method to clear the old nozzle before taking it out, and realized the printer was silent.  The top fan on the printhead was not spinning.. I gave it a push and it started spinning.

 

So right now it will spin if I turn the printer of and on.. but it's not sounding like a good spinning fan.

 

 

ah...  something is impeding the fan...   

You get little strings from some filament that get into the fan and wrap around it, best to give the fan a good clean and pull any strings out. If its all clean and still not sounding right then i would replace it as its a cheap but very key part of the printer.

[smorgana 0]

On 9/25/2020 at 4:47 AM, Carla_Birch said:

You get little strings from some filament that get into the fan and wrap around it, best to give the fan a good clean and pull any strings out. If its all clean and still not sounding right then i would replace it as its a cheap but very key part of the printer.

I took the printhead apart enough to get a look at the fan without taking it out..   I could not see anything impeding the fan.. no filament hanging in the heat sink, etc, yet the fan while spinning made a kind of ticking sound just like a filament was contacting the blades...like a playing card in a bike's spokes.  anyways its a 12 dollar part so I ordered one figuring I'd swap in a new one and on disassembly I'd have a better look.

 

Well the part is backordered, so I figured I could keep printing by giving the fan a push when I turn the machine on.. it stays running after the first push...   So I printed a few days on it and then it stopped needing a push...  then after another few days it stopped making the noise..

So it must have been a piece of filament I could not see and it eventually worked it's way out...   I'm going to let the backorder go through just to have the part on hand.

 

also in this adventure.. I came to the conclusion that it was not all the fan that caused the filament to get stuck... The filament spool itself could have been the problem.

 

I used to keep the printer in my basement.. with humidity around 65% -- which is bad.. but it worked for me.   This spring it was very rainy... and my dehumidifier stopped working for a few days so the humidity went up to 80 ish...   I got the dehumidifier working again, but it was so far behind, that it only got the humidity down to 75%..   The spool that was on when it got stuck was sitting in that humidity level.    I later read that humid filament could case the feeder to grind more easily into the filament.

 

I moved the printer to our living level, and the humidity is about 45%...  and once I made sure the hot end fan was running I put in a spool of filament that I've been keeping upstairs...   it got stuck immediately... not the fault of the fan but of being too soft from humidity and the feeder chewing into it.

 

So I threw out that spool... put in a brand new spool and it has been working fine.   I also bought a dryer...  so I can swap spools out every few days and dry them..

 

I am also now keeping all spools in a rubbermaid bin.. with a desiccant and a humidity meter.... it's keeping the bin at about 35%...