i was a lot reading in this forum, and got many Problems solved (x-Axis shifted layers, bed leveling, etc…)
My results where getting better and better, but suddenly (after round about 50 prints) the filament get’s stuck (there was nothing coming out any more).
Slightly sad i got it out and tried to clean the white shaft after the nozzle, reassembled the extruder and used a small nail to “free” the nozzle too.
After that the next print seems to be good again.
The next day i wanted to start another print, and bäähm it stucks (there still was filnament coming out but, less and with air in it) again, and i repeated the procedure.
It was printing once good, and yes it stucks again.
After the “full” stuck, the two other times, the filament came still out but it was like it was air in it. Tried other filament but this seems not to be the problem.
My question, how can i avoid that the filament got’s stuck after each cool down.
The Problem was the other 50 prints before not. And i changed filament often (different colors, etc…)
Changed all ready the driver voltage, played around with the screw with the spring and removed the filament after printing.
i would answer the question with a yes, am i sure, not 100% so here are coming 2 pictures… drensec.com/downloads/nozzle_ntc_1.jpg drensec.com/downloads/nozzle_ntc_2.jpg
It seems that there may be a small gap, but in real this gap may be smaller than 0.5mm, i was thinking about
to glue the thermistor on to the hot end (i have some thermal adhesive for heatsinks - used this also for the driver stages)
On the other hand side, i also tried tested to print with higher temperatures, and the effect wasn’t significant.
i actually only use PLA and tried different manufactures.
Before the initial stuck the filament was always good to change and i noticed no bigger differences in print quality from color to color or manufactor to manufactor.
In the beginning (round about the first 10 prints) I was printing at 195°C, but later (after using white color and some burned point ocured on the print) i lowered the value back to 190°C.
At the first stuck i print at 190°C but i also tried to raise this value in steps up to 205°C.
There was no significant effect.
I also use a 3mm glass on the headbed to level the bed at 50°C.
Definately a temperature problem.
Please look closely at the pictures: the sensor is not in the hole but above it.
This will generate huge temperature variations (please check the temperature curve in Repetier).
If you use Kapton tape you can use a small strip (4 mm or so) of Kapton to fasten the NTC even better.
This solution also works for nozzles without a hole to mount the screw on.
I also suspect that the use of Kapton in that area fo isolation helps to stabilize temperature when the fan goes on. Maybe someone can comment on that?
Robert
