Ultimaker Original+ Hotend issue

[Julian28010 0]

Hello,

I have something weird going on with my hotend. I tried printing a part yesterday and noticed, that the filament stopped extruding. I thought that there was a problem with the extruder but when as I took the Bowden Tube out of the hotend I saw a big chunk of PLA at the end of the tube that there was no possibility for it to go into the Teflon coupler (Filament softened in upper head) . As I took the whole hotend apart to clean it I saw the PLA stuck in the peek insulator.

I cleaned it and put it back together and the print worked for 10 minutes and then the whole problem appeared again...

Any suggestions?

With best regards,

Julian

Edited May 14, 2017 by Guest

[amedee 349]

I would say that you have too many / too big retractions pulling heat in peak and Bowden ....

(And maybe combined with printing a little hot or at a flow the hot end can't sustain)

[Julian28010 0]

I would say that you have too many / too big retractions pulling heat in peak and Bowden ....

(And maybe combined with printing a little hot or at a flow the hot end can't sustain)

I did several testings yesterday and today and after them I can't imagine that there is something wrong with the retractions. (I heated the Extruder up to 200° Celsius and extruded 10CM with the UltiController and the same happened again, so I dont think it has something to do with retractions and too much Filament coming through) I also tested my Teflon coupler and it don't seems to be damaged at all. Any other suggestions?

Edited May 16, 2017 by Guest

[geert_2 557]

Could it be that the nozzle gets blocked, so the melt has no other way to go than upwards?

[Julian28010 0]

Could it be that the nozzle gets blocked, so the melt has no other way to go than upwards?

Yeah, that could be a reason! Any idea, what I can do to test it?

Edited May 16, 2017 by Guest

[Julian28010 0]

Could it be that the nozzle gets blocked, so the melt has no other way to go than upwards?

Yeah, that could be a reason! Any idea, what I can do to test it? Or fix it?

[amedee 349]

How does a cold pull (atomic) look like?

As @geert_2 is suggesting there might be some residue in the nozzle.

A couple of cold pulls should also clean-up the nozzle.

Note that If you have printed anything else than PLA (ABS, XT, ...) before, use that for the cold pulls as well.

Worst case, unscrew the nozzle for inspection (after cold pull, otherwhise it will be full of filament and you won't see anything!)

[rowiac 53]

My guess is also a partially blocked nozzle. Since the filament was bulged above the teflon coupler, it's probably not the coupler. Even so, you should consider getting a spare coupler and nozzle since they do wear out.

I had a persistent problem with clogs and under-extrusion and changing the nozzle is what finally fixed it.

[geert_2 557]

First do cold pulls or atomic pulls as the others said (search for the manuals on this site). Or if you want to do a more gentle pull, try my method. This method does not require brutal pulling, but works by cooling deeper, and by gently wiggling and rotating the filament prior to pulling. See:

https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

Then you should be able to see through the nozzle from above, or from below with a mirror: light must be shining through.

Inspect the pulled-out pieces: are there bits of residu or foreign parts in it?

I also sanded down a needle (one with a glass ball, so I have a good grip) to a diameter of 0.39mm. Normally they are 0.50mm here, which is of course too wide for my standard 0.4mm nozzles. Then after doing an atomic pull, I gently (!!!) poke through the nozzle from below. This also helps removing accumulated residu in the nozzle tip. But do this very very gently: steel needles are much harder than the brass of the nozzle, otherwise you would damage the nozzle.