Filament stuck in printhead

[mamastoast 0]

So we've been having some issues with our ultimaker 3. It started out with the printer seemingly randomly failing it's active levelling and then starting to underextrude once in a while. I was able to temporarily fix these issues but now I think something has well and truly gone wrong.

I was attempting a print and it ended up entirely failing by barely extruding anything and the flow sensor stopping the print.. When I then tried removing the filament I realised that it is very much stuck in the printhead, I've tried gradually heating it up to 270 and it remains impossible to pull out.

I've also noticed the the fans don't seem to work anymore, so that may be related. Is there a way to manually start the fans in the controls? I've been looking but can't seem to find the option.

[Enigma_M4 119]

Hi,

the print core cooling fan (the big one in front of the print head, under the magnetic flap) is automatic controlled and always runs when at least one print core is hotter than 60°C. It can not be controlled manually.

So if it doesn't run at all, that's the culprit.

Check the fan for residue and small stringings of filament that can block it (as it is recommendet in the maintenance shedule at least every 3 months) or replace it.

 

By the way: how did you manage to implement the flow sensor to the ultimaker 3? Or are you talking of an S3?

Regards

[mamastoast 0]

THere were some stringing and I've tried to remove it. The thing is that when just trying to turn the fan manually, it rotates with no issue, so it doesn't seem like it's being stopped from moving.

Hmm I guess it may be a S3 then? I wasn't the one who bought it so I'm not 100 on the name.

Do you have any idea how I should extract the stuck filament? It's very much stuck and I can't figure out how get it out. As I said I've tried pulling it at temperatures from 180 til 270 with no luck. It feels like it's moving a little bit and then gets stuck somewhere after moving a mm or two

Edited August 6, 2021 by mamastoast

[Enigma_M4 119]

I've no advice to extract the stuck filament, as luckily I never was forced to do so. Personally I'd try the filament unload procedure of the material menu, using the feeder to pull out the filament, either with or without pre-heating the printhead, but I don't know if that's a good advice, because the filament in the print head may have expanded a lot.

Perhaps @gr5 or @geert_2 can help, as afaik they're experienced with this issue.

Regards

[geert_2 557]

I do cold pulls regularly to clean the nozzle, but I never had really stuck filament. The worst I had was that it got partially stuck due to worn-out teflon couplers on UM2, causing a thickening of the filament in the coupler. Normally it should come free as soon as the plastic starts melting, thus ca. 60-70°C for PLA, and 90-100°C for PET. If it is still stuck at elevated temperatures, it seems the temperature once crept up into the filament, making it now stick somewhere way above the heating zone, in what should be the cold zone? This could indeed have been caused by a non-working fan. Not sure how to handle that safely, without doing further damage to the nozzle...

 

[timotub 1]

Could this possibly be detected in a future release of the ultimaker firmware, maybe during nivelling? - I have faced this issue today as well..

[Carbon 28]

It's only the brass element that's heated, if the filament is stuck higher up the nozzle, an additional heat source is needed. 

 

Try a hot pull using PLA first, failing that....

 

Try heating the top end of the nozzle with a heat gun. heat the nozzle in the printer to 270°C, remove it from the printer, taking care not to touch the nozzle itself (the printer will throw up an error when core is removed, but......) Then heat the top part with a heat gun say about 100°C and try a top pull.

 

 

[talker13 0]

Pretty sure I'm seeing a similar issue.  Can guarantee that the filament is melting at the top of the print core.  I can see where it has ballooned out at the top of the print core and will no longer feed into it.  Additionally, because of the ballooning, the filament cannot be pulled out either.   I had to wind up using a small saw to cut through the filament to pull out the core.

I have had this with 3 cores now.  Originally, it happened with an older core, but I tried a new one and then a new core with a brand new filament as well.  I tried hot pulls as well (didn't work) and cannot even push it through (I have tried heating the core to 250-270 and pushing using a cleaning rod) and it doesn't budge.

 

[Torgeir 242]

18 minutes ago, talker13 said:

Pretty sure I'm seeing a similar issue.  Can guarantee that the filament is melting at the top of the print core.  I can see where it has ballooned out at the top of the print core and will no longer feed into it.  Additionally, because of the ballooning, the filament cannot be pulled out either.   I had to wind up using a small saw to cut through the filament to pull out the core.

I have had this with 3 cores now.  Originally, it happened with an older core, but I tried a new one and then a new core with a brand new filament as well.  I tried hot pulls as well (didn't work) and cannot even push it through (I have tried heating the core to 250-270 and pushing using a cleaning rod) and it doesn't budge.

 

 

HI @talker13

 

Three times like this, -this looks like your front fan does not  work properly..

When this happen, heat will climb upward into the normal "cold zone" and filament is "glued" inside the tube.

Check to see if the front fan is blocked by filament strings etc., -or if it's just stopped for other reasons.

 

Thanks

Torgeir

 

[gr5 2,167]

To get that filament out you will have to disassemble I think.  Video:

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

 

[rooiejoris 5]

Same problem and a material remove tip.

 

Have the same problem after every print since last week as well. Checked the fan immediately after the first failure since that was my usual suspect. Fan is running... hard to tell if it is running normal speed or a lot lower though...

Then switched to another (same size 0.4mm core) same problem...

 

I have something else though, I am running an gcode file generated in the past and needed a new batch of these objects. The printer (UMS5) says that I wouldn't have optimal performance, but didn't expect this... : )

 

TIP to remove the material which works for me:

- heat up to 245-260 deg

- wait a while

- then go back on menu to the material and push the three dots to right to 'move the material'

- pull (really a lot!) and hit the move button 2 times per second.

(don't keep ou finger on it since it will go to fast and grind into you filament)

 

Try to avoid to break the filament, but I guess you don't do that on purpose...

 

Interesting that this happens the last few weeks...?!

Have to check the firmware and the exact cura version i used for these files..

Next up is double checking or replacing the fan to see what happens...

 

 

[talker13 0]

Couple things.

1.  So far, I have only used AA0.4 cores and had the issue.  I am loading a AA0.8 to test.

2.  Fan is definitely running when I heat the core.  Haven't watched a print yet.

3.  It has only happened when printing from Slot1.  Slot 2 has printed fine.

4.  Currently running firmware 6.2.2.0 though I think it happened on the last version as well.

5.  Will test rooiejoris  method if it happens again.

[rooiejoris 5]

update on last print behaviour...

didn't try to remove the material, but started right away with warming up the core

I noticed that the fan was not on untill I opened the lid (I think?!) or above about 150 deg...

Then the fan turned on. I suspect moving the lid did the trick, so will check with a new fan or check the wiring.

 

BUT...  When I tried to remove the material I noticed it was not stuck at all...?!?! like 'normal' behaviour...

I also noticed an extremely large prime blob which I cannot declare.

 

to be continued....

[gr5 2,167]

6 hours ago, rooiejoris said:

noticed that the fan was not on untill I opened the lid (I think?!) or above about 150 deg...

Aha!  So there could be loose wires near the door hinge but it's easier to check the connector and the connector often pulls out a bit (partway).

 

There are 4 very long screws oriented vertically in the 4 corners of the print head.  Remove the rear two (the head will still stay together nicely).  Then pop off the rear half of the top panel that holds the cable in place.  Once open, check that cable - it doesn't come out of the connector easily because it is latched in but still - push the connector back down.  Do this while print head is in the corner of the printer so you don't bend the rods.

 

While reassembling if the cable seems like it can pull/slide - maybe add a shim of some sort - maybe a piece of paper between the cable and the clamping top of the print head.  To keep the cable from pulling out.

 

[rooiejoris 5]

That is what I will check indeed...!

(but so far no problems anymore, maybe just lucky...)