Hi Federico, can you try to use a different nozzle to be sure that it’s not the problem?
Ok, I’ll try to buy one during the weekend. In any case, it’s a good tool to have in the lab
After you do all the easy checks…like making sure there are no stringy bits binding the filament in the bowden tube, and after checking and maybe cleaning the extruder gear, and trying a different nozzle…I would think that it is likely to be the teflon coupler that needs replacing. They are a consumable item and I have been through a couple.
Try to put a litlle bit of WD-40 inside the bowden tube, it as solved my extrusion problem with the Ultimaker 2GO.
Regards
Marc
Had same issue, replaced the teflon coupler. That was causing this issue and the problem was solved!
This is wat you need → http://3dsolex.com/teflon-replacements 27
I replaced it with this one, and the printer prints like a charm 
That’s a cool suggestion, I’ll try to print one of them and use it 
Cheers,
Federico
I’ve seen this issue before when the nozzle seems to be clean, I’m wondering what your PTFE coupler looks like and if it might be worn out? I change mine about every 4-500 hours but it depends what temps you normally work at. It’s a good suggestion below with poking something into the nozzle. I use a 28 gauge needle (0.36mm), and you can find them any medical supply store. I would also look at the gear box in the back. Sometimes when small bits of plastic accumulating in it can slow the forward movement thus causing underextrusion.
I have a problem that looks like this pretty frequently. It may or may not be the same thing, but usually for me it’s that the nozzle isn’t “primed”. That is, the material has been retracted at the end of a print or when I aborted a print and the start g-code dis not sufficiently compensate for this before attempting to print the first layer.
If that’s the problem, there are tqo solutions:
1. Go into maintenance>advanced>move material and spin the dial until material comes out, then hit cancel and start the print.
2. Change your starting g-code so that it includes a command to extrude a bunch (I call this “priming” the nozzle) before beginning the first layer.
I suppose the other possibility is that your filament tangled… I always forget to check for that first.
by the way, glad the pinecone lamp came out nicely. Sorry for never getting back to you about our g-code analyzer. Unfortunately it only supports rep-rap g-code and does not yet support ulti-gcode.
No problem at all, I’m quite sure that the problem wasn’t the Gcode. I’ll try to order a new Teflon part: honestly, I believe that it is the problem.
I had a similar problem and it turned out to be the extruder. The gears inside the new feeder had begun to push each other apart sideways, down the shafts. As a result, the gear on the stepper motor had moved down the shaft toward the motor, resulting in a loss of movement to the filament. At first I thought it was grinding the filament, but there were no marks - it simply stopped turning the gear.
To fix it, I have applied glue to the shaft of the stepper motor and reattached the gear, in the same position down the shaft as in the upgrade video. As a precaution, I have also glued the bigger gear onto its shaft end.
Hi Jockspice,
Thanks for your suggestion: I have already checked the extruder and, apparently, it’s working in a correct way.
@idamartha @Jaime_1 @SlashDev @jockspice @Clean3D @bramthats @Jamburger @will_kostelecky
Thanks to all of you! Finally, I solved the problem. I disassembled and checked all the hotend. The problem was some PLA wedged between the nozzle and the Teflon.
…And the problem is back, sigh!