[Solved]Filament stuck in nozzle (UM3, PLA, AA)

[Brannfjell 1]

Hi,

I just recently got a new batch of PLA from my dealer and they obviously made some huuuge improvements to it since it's not nearly as brittle as before... however im experiencing a new problem...

Im running my primary AA print-core

PLA (White) 2.85

205 C print temperature

100% Flow

During my third print job with this PLA it stopped extruding and i discovered it after perhaps one or two hours before. Once i discovered it i aborted the print job (remotely)

When i got back to my printer the feeder had chewed trough the filament enough to not get a grip any more.

My first idea was, as described on this site;

1. Remove tubes

2. Increase temperature to 180C

3. Push filament down to manually extrude

....

This didnt work so i increased temp until i hit 230C...

A little bit of filament did come out, but i suspect this was filament that was just in the lower parts of the printcore.

Then i tried the other way, pulling it up... no luck with this either...

Increasingly frustrated i started raising the temp but once hitting 300C i gave up and now im here writing about my problem hoping someone has some word of advice for me before i go all king-kong on my beloved UM3.

Edited March 9, 2017 by Guest

[DidierKlein 729]

I hope you didn't burn the pla to badly inside... 300°c is way to high

Do you have a small needle less than 0.4mm in diameter that you could insert in the nozzle (from the bottom) in order to clear the plug?

Acupuncture needles or copper wires from electric wires should work.

It's really weird that you can't pull it out either

[Brannfjell 1]

I did a whole lot of tries to push/pull before going up to higher temperatures....

I strongly doubt I will be able to apply any significant pressure from underneath compared to the pull/push force. I do not want to apply any more force by pulling/pushing since I'm afraid I'll break/bend something.

Anyway I tried pushing a 0.4mm wire up from underneath and it got 20mm up before it stopped.

Could the PLA be stuck above the heated area?

Could a possible solution be to use a heatgun to heat up the upper parts of the Print Core? how would would it require to be before most PLA would be soft? (Got a temperature adjustable heatgun)

Im also considering to buy a nozzle drillset... a new print core (been looking at 3D Solex Hard Core Six Basic-pack)

[SandervG 1,521]

Hi @Brannfjell,

thank you for your post.

First of all, I would strongly recommend against using a heatgun. You will probably break something before you fix something.

Is there still any filament in your feeder, or is it all out?

Is it only still stuck in your printhead / Core AA?

Are you sure it is PLA?

I would recommend to only pull. If you decide to push, make sure your printhead is parked in the corner of your build Ultimaker, to prevent your force to bend the rods.

If it is indeed, PLA, raising the temperature to 200ºC should be enough to pull it out from the print core. Especially if you give it a minute or two before you give it a pull.

[Brannfjell 1]

Filament is still stuck like in my first picture. Only difference is that i now know that the bottom 20mm is clear since i can put my 0.4mm wire up.

If there are different parts of the Print Core AA that has different names I'm not sure what part is considered the Head... anyway the bottom 20mm is clear, the rest i have no idea... except that its damn hard stuck.

It's labled PLA, i ordered PLA and it behaves like PLA. The previous prints completed prefectly with PLA-settings. Only thing that is different from my previous PLA is that this is not brittle and does not break easily.

Printhead has been in the corner all the time while i've applied any kind of force and I've left it for several minutes with heat on.

I will not use a heatgun then...

Considering my next step to be chopping of the filament and removing the printcore

[Brannfjell 1]

Ok... so this is what i think;

Heat has creeped up and melted some PLA above the heat element and this PLA wont melt now while im trying to remove it.. and since this PLA is a improved kind it doesnt break as easily as PLA normally would.

The picture is from my other AA Core.

The first 20mm is open and this is the area that gets heated by the heating element.

Then there is a clog that doesnt get heated up, this also prevents me from pulling the filament up.

I will now cut the filament

Remove print core from printer

Seperate the heating element, Chip, plastic and filament mount-pipe

Heat up the Filament mount-pipe (blue)

Remove whatever i can, and if stuff is still stuck i will use a drill to remove whatever remains. (this should be in a 2.85mm area, not 0.4)

Meanwhile my second AA Print-Core will be in use and I'll probably order the 3D Solex Hard Core

[Brannfjell 1]

So i started disassembly, and well... i'm surprised.

now i can see trough the rest of my nozzle... so this problem seems to be that my PLA is stuck in the top of the pipe.

the biggest part of the PLA is 3.6mm and the thinnest 3mm (thinnest @ bottom)

The PLA itself must have deformed/expanded while the feeder has been pushing filament towards the nozzle faster than what my printer pushed it out... (but my flow was only 100%)

Anyway - im happy this is solved and hope my core still prints good when i put it back in one piece.

[tomnagel 126]

Did you contact your reseller? The print Core is not a user serviceable part, since the heat break is very easy to destroy.

PLA getting stuck in the cold zone is impossible if your printer is working fine. Please check if your front fan is running when print cores heat up.

[Brannfjell 1]

Did you contact your reseller? The print Core is not a user serviceable part, since the heat break is very easy to destroy.

PLA getting stuck in the cold zone is impossible if your printer is working fine. Please check if your front fan is running when print cores heat up.

 

I will resume printing and if the problem returns I will contact my reseller. However; i believe this is a side effect of the new PLA. Since this PLA is much less brittle and wont break easily the trade off is that it deforms rather than crack...

I only ever used filament from the same reseller as ultimaker-reseller and they are super serviceminded so i doubt i will have any problem with them if this filament causes more trouble.

[SandervG 1,521]

 

@Tomnagel, in his first post Brannfjell describes he raised the temperature to 300ºC. Should the heatbreak and front fan prevent affects from temperatures this high too?

[tomnagel 126]

Yes. If the front fan is working, the double heat break in combination with the front fan prevent the TFM insert from burning. We've designed the hot-end for use up to 350 degC.

The limiting factor in the printer is currently the silicon flap in the bottom of the printhead, which is rated up to 280degC. That's why we specify 280degC as the maximum operating temperature.

But 300 degrees will burn most polymers inside the hot end. But nothing a good cold pull won't solve.

[Brannfjell 1]

Figured people might be interested to know that I´ve printed aprox 100g of filament with no problem today.

Ofc did some cold pulls before printing with the printcore...

[swordriff 119]

The filament can get stuck in upper part of core under this condition:

If you "move material" back towards the nozzle just after finished print, or after manually heating core, then "half liquid" plastic will try to get stuck in areas not designed for this.

Allthough the "waiting" and "moving" of the material in the UM3 can be a bit annoying, especially if you are in a hurry, I find it is very cleverly designed indeed- it avoids this kind of problems.

Please can you confirm that you did some manual moving material before it got stuck in upper part?

I have fiddled around a lot with the UM3 and find very few faults with it. The Original cores work excellent and I have had problems only when I have fiddled too much or been in a real hurry:

Things to avoid:

turn off printer to make faster reset

moving material just after print is finished, especially towards nozzle (!!!)

turn off printer any time when it is not in resting status.

[tomnagel 126]

Yes!

Although it might be irritating waiting for the printer finishing up, those procedures have been implemented to prevent problems later on. For example, before retracting the filament to parking position, the printer lets the hot-end cool down just a little bit, to prevent creating a very thin part of filament, with a thicker blob behind it. When you have such a blob hanging on a thread at the end of your filament, chances are this blob ends up in your feeder when unloading the material later on.

Another example: unretracting filament and priming is done at excruciatingly slow speed, to prevent grinding when the filament position is not what the printer thinks it is (user was fiddling...).

[Brannfjell 1]

@swordriff

There was no tampering with the filament before it jammed, it happend during a print, and there was no change of filament either... had been like 3 prints before the jamming occured.

What might have started as a normal lower nozzle clogging could have evolved to this due to the print job proceeding with a clogged nozzle. The feeder kept feeding even after the nozzle was clogged since there is no smartness to detect a failed job. I aborted the print as soon as i noticed that there was no filament extruding, but this was after the feeder had chewed trough the filament.... so probably a lot of pressure towards the clogged nozzle causes the filament to deform in the piped area prior to the hot-end

[tomnagel 126]

I am still pondering how this could have happened. the temperatures in the cold end of the print core are well below 60 degrees, and so high up certainly below 50.

The feeder can push with about 80-90N, that can never be enough to deform the plastic. Try it yourself, even double the amount will not deform it.

So either the front fan was not on or blocked, or the front fan bracket was open. That could lead to higher temperatures in the cold zone.

[gr5 2,265]

@tomnagel - he used some kind of weird flexible pla that does deform.

@Brannfjell - did you check that your 3rd fan is working? It's in the part of the head that swings open. You should hear it come on any time a nozzle gets above 60C.

[ultradryan 9]

Hi people

I hv similar issues.

I use normal PLA.

I hv the 3D Solex hardcore on same material, same print setting, same nozzle size as the original UM core.

The print will most certainly fail after a few layers.

The print looks like its experiencing under-extrusion.

If I switch back to the UM original core again, with all the same setting, it works like a charm.

I am starting to think there's sth wrong with the nozzle design...

I hope to see if any one find a fix here.

It is very very frustrating.

I have two 4mm nozzles, both experience similar issues.

I even bought their 2.5mm everlast nozzle.

very frustrating, it just wont work on my UM3.

:angry:

[gr5 2,265]

Contact @swordriff at 3dsolex if you haven't already.  Yours may be defective and he is quite good about exchanging plus he might be interested in examining your hardcore carefully to learn about possible potential manufacturing issues.

Edited August 5, 2017 by Guest

[enchantedsord 0]

I'm in a similar boat here.

I had one build core already get the filament stuck inside the upper tube from what I can tell. I swapped my 2nd core over and that was printing fine. Come home today to find it's is also clogged now.

The first core I snapped the pva just below were it goes into the tube on the core and I feel i'm pretty screwed.

The 2nd one still has the filament attached with a good amount to play with.

How the heck are you suppose to fix this.

Also how is it this happened to me with 2 different filaments on two different cores.

I haven't tried sticking anything up the tip but it seems to be stuck higher up.

[SandervG 1,521]

I'm in a similar boat here.

I had one build core already get the filament stuck inside the upper tube from what I can tell.  I swapped my 2nd core over and that was printing fine.  Come home today to find it's is also clogged now.  

The first core I snapped the pva just below were it goes into the tube on the core and I feel i'm pretty screwed.

The 2nd one still has the filament attached with a good amount to play with.

How the heck are you suppose to fix this.

Also how is it this happened to me with 2 different filaments on two different cores.

I haven't tried sticking anything up the tip but it seems to be stuck higher up.

Is the fan on the front of your printhead still running? It should contribute in cooling the filament so it can not expand and grow too thick. You could check if the wires are properly connected, or if there are no small strings of filament preventing the fan from blowing.

Could you add a photo of your build / support core on the situation? I'm sure we can help!

[enchantedsord 0]

I checked the fan it's it's good. I was finally able to free the filament stuck in the core #2 lets call it. The one with the filament still coming out of it.

The first core is my issue now as the filament is stuck below were it enters core but above the melt/heated area.

Anyone know how you might get his out without taking the core apart?

[gr5 2,265]

Just take it apart.  It will void the warranty but it's not that hard.  It's very easy to break if you don't watch the below video but really it's not so hard:

Rats - the link has an 8 followed by a D which turns into an emoticon and wrecks the link.  Just search youtube for "um3 core disassembly" or paste the below link into your browser.

https://www.youtube.com/watch?v=Ln_tMz8Dwd0

Edited August 19, 2017 by Guest

[chuckster 0]

 

For what it's worth, I just had the same thing happen with Matterhackers  PLA. I was able to remove the bowden tube but could not remove PLA from nozzle.  Finally I cut the PLA 8" from top of nozzle assembly, chucked it into a drill pulling lightly on the filament as it rotated in the drill. Friction heated the PLA and it pulled out with ease.