And my problem is that when it goes over the top of the hexagon it sometimes slams the nozzle on it and then it flinch the little vertical part. I hear small popping as it hits the print every time. Only when it’s around top of that hexagons. Like this:
I tried half acceleration, more supports but nothing seems to help that much. Once I added so much support that I was unable to carve them out and had to cut it. Is there some hints on what to do in this case? All other prints looks ok. Nozzle is not dragging or something afaik. Only this one has problem like that. Thank you.
For example it happened here on the top and now it looks like this
I did in the past print a very similar structure. A CNT for my work memorial cabinet. That experienced similar issues which I overcame with the usual anti-curling measures.
Note: Curling occurs when the newest layer is cooling down and hence shrinking. If that occurs on a curved path on top of a cooler layer, it will pull up the local geometry. The result is audible on subsequent paths. Where curling occurs again making it an amplifying defect.
Adaptive layer lines: By lowering layer height on the overhangs, volumetric heat input was lowered so cooling was much more even. This drastically reduced curling.
Slowing down: This is not really desired, but it is effective in combatting curling. Lowering acceleration is good too for the fine stems as printer needs a few mm to get up to speed, but only effective on short travel paths.
Avoid crossing paths: Usually not a problem with PLA, crossing paths can become a problem where curling occurs. Use Monotonic for all surfaces and internal infill pattern and gyroid or honeycomb for Sparse infill. You probably do not have Sparse infill on that print, but curling is a generic problem.
Double printing: In rare cases, there’s so little to print per layer that extending layer time may be neccessary. Since just slowing down to meet layer times only keeps the hot nozzle in the problem area longer, it can be beneficial to print two identical objects simultaneously or at least enforce a prime tower.
Hope this helps and
PS: I did manage to print my final CNT completely without supports as the 30° angle was doable. Not sure about that end ring you have though.
So probably it is not your nozzle that is destroying the model, it is the model that is curling up and catches the nozzle as it is passing by.
Curling up occurs when you have a partial overhang that shrinks while cooling down. The filament that sticks out the most curls up and when the nozzle passes by it hits the curl.
Besides the solutions the previous poster mentioned you can also improve things by putting a lot of cooling on it. Cooling it faster makes sure it does not have the time to curl up as much.
