Under extrusion (maybe?) after two hours

[LastZactionHero 0]

I'm running into an issue on an Ultimaker II- after 1.5 -2 hours, it just stops extruding.

The first part is great- nice looking print, pretty fine, maybe even too much material flow. Then, every time, after about 1.5 hours, it just kinda quits.

Below are two photos from recent prints, one tall and skinny, and one short and flat. Same symptom in the same time, so it doesn't seem to have to do with height. Same with different filaments.

Material pressure settings are set a bit on the low side.

Thanks for your help!

[IRobertI 521]

Is the fan on the back side of the head running? It should either turn on immediately as you turn the printer on or after the head reaches ~40C depending on how old your printer is.

[LastZactionHero 0]

The fan is running. Starts immediately.

My theory at this point is that the filament motor is too hot, and it's causing the filament to melt/soften in the feeder. I've seen this posted around, but not sure what to do about it. It would sort of make sense why this would occur after a regular period of time. The knurled knob is hot to the touch.

Edited October 24, 2015 by Guest

[IRobertI 521]

Is the filament ground down or squished flat? If so, then yes, that could indicate the feeder motor hotness being a factor. You could try mounting a small fan on the back of the feeder or pointing a desk fan at the back to see if that makes a difference. IIRC there was someone in Brazil that solved a similar problem that way. But that was in the middle of a very hot summer with high indoor temperatures.