Strange filament cloging issue

[Guest]

Hey guys this is an odd one, I have proudly been an owner of my Ultimaker 2 for over a year now and have never come across a problem like this one. Mainly the issue is that after a little while of printing, say maybe 15-30 min, the nozzle will clog and stop extruding plastic. Now unlike other clogs the nozzle is completely clear of any debris, instead it is due to the filament bunching up in the hot end. see here for a photo https://www.dropbox.com/s/z7mgw6dnli5ktxo/Photo%20May%2015%2C%209%2001%2003%20PM.jpg?dl=0

Current print settings are:

filament diameter(I measured it) 2.85mm

Temp:200-210c

bed: 55c

speed: 50mm/s

retraction: 4mm at 35mm/s

If anyone has any clue why this is happening during my prints and may have a solution any help would be greatly appreciated.  Also feel free to ask any questions as well.

Edited May 16, 2015 by Guest

[Labern 775]

It's probably the ptfe coupler and may need to be replaced. But also check and make sure the 3rd fan at the back is on 100% of the time. If this stops it can cause these issues.

[Dim3nsioneer 558]

Yes, there is a small bulge before the narrowing (the latter of which probably comes from pulling out). This bulge might be an indication that there is a small gap between Bowden tube and Teflon coupler. Checking the Bowden coupler as suggested by @labern is certainly the best thing you can do. Do also check the Bowden tube itself. If it has deep scars around the spot the Bowden coupler you might want to consider replacing the Bowden tube (you could actually also cut off a few mm to make the Bowden coupler holding the the Bowden tube at a clean spot, but you would have to cut very accurate to have a proper fitting between Bowden tube and Teflon coupler again).

[swordriff 119]

Agree Teflon faulty!<

As it gets hot after 10-20 minutes, it collapses onto the filament.

You can save the day by loosening the 4 long vertical screws in the print head assembly, it releases the pressure. They only need to be as tightly wound as by "female fingers". (....)

[Guest]

Yes, there is a small bulge before the narrowing (the latter of which probably comes from pulling out). This bulge might be an indication that there is a small gap between Bowden tube and Teflon coupler. Checking the Bowden coupler as suggested by @labern is certainly the best thing you can do. Do also check the Bowden tube itself. If it has deep scars around the spot the Bowden coupler you might want to consider replacing the Bowden tube (you could actually also cut off a few mm to make the Bowden coupler holding the the Bowden tube at a clean spot, but you would have to cut very accurate to have a proper fitting between Bowden tube and Teflon coupler again).

I have checked the connection and all appears to be fine, the only thing is i have already replaced the Teflon coupler recently as in only about 2 months ago and it still is 100% circular. The bowden tube is also snugly resting agents the coupler with no air gaps.

[swordriff 119]

Could be clogged NOZZLE hole (0.4mm hole) itself, or intermittent temps sensor.

When it stops, is the nozzle realy hot? Touch the nozzle from the ouside with filament. Must melt a big dent immediately

[Guest]

Could be clogged NOZZLE hole (0.4mm hole) itself, or intermittent temps sensor.

When it stops, is the nozzle realy hot? Touch the nozzle from the ouside with filament. Must melt a big dent immediately

Yes the nozzle is still very hot at at least it feels very warm, secondly I don't believe it is a clogged nozzle hole because I just did a test extrusion and measured the width of the extruded plastic and it comes out to exactly 0.4mm give or take 0.02mm. Unfortunatly i dont have a IR temp sensor so I cant check the true temps of the hot ends.

[swordriff 119]

feels hot/ still warm is not good enough. 165C feels warm too.DOes it MELT filament on tht outside when you touch it with it?

[Guest]

feels hot/ still warm is not good enough.  165C feels warm too.DOes it MELT filament on tht outside when you touch it with it?

Yes it still easily does melt filament then touching the nozzle.

[swordriff 119]

something wrong:

YOu checked it extrudes hard.

You made atomic and it comes out clean

It is hot and melts plastic.

Only thing left is that the 0.4mm hole itself is clogged, or that the teflon coupler collapses when hot, or both.