scobo wrote:I ran into similar trouble with my stock hotend.
It became very unreliable, even with ABS after around 150 hours printing.
No amount of cleaning made much difference.
I gave up on it and fitted an E3D Lite (cheaper than full fat E3D but limited to 240°C) which is producing fantastic prints and has so far been 100% reliable with every type of filament I've thrown at it.
Can't recommend it highly enough.
I KNOW ! Drives me nuts. I can almost "feel" that somehow maybe the inner walls of the tube are having microscopic abrasions that somehow create friction that prevent the filament from sliding. The friction force is so high that pulling on the filament will break it but will not budge. I believe that even 5 mm of stuck filament generate enough friction that it cannot be pushed out, it has to be drilled.
I am trying out a process of elimination waiting to get the MK8 head delivered from China. First is to try an identical new original left Duo head to see if it is head related. If that works, I will swap in the old heat tube into the new heat block/nozzle to test the internal abrasions theory while also jacking with the old nozzle to see if I can clean it better.
I can hear fans running, but I did not check if BOTH run (I believe there are 1 per head, would be funny if the left one died and I did not notice, maybe that is why the feed tube would get too hot). Hmmmm.
But when the filament is cold is slides perfectly. temperature is good, fans work, yet it swells and gets stuck. Maybe it sucked moisture, I will also try brand new filament that was sealed in the original bag.
I have to check how many hours of printing I have.