Curling on Overhangs

[aerouta]

So I have noticed a new issue and it has been kicking my tail for the past few days. I am unable to successfully print over hangs. This issue gets worse as I lower the layer height.

Here is a result from what I have been testing. I quickly drafted this parts with different angles on each side.

the angles are 50/55/60/65. I know these are steep but i feel the max should handle this.

I have search online for a solution but they are all over the map.

Any suggestions for improvement?

By the way, the prints are pictured upside down...

[Polygonhell]

There are a couple of reasons why it happens.
The first. Is the filament is stretched as it leaves the nozzles and contracts as it cools, so steeper overhangs will tend to do this.
The second is filament not getting a chance to cool before the Hotend deposits another layer, and the hot end tends to pull it towards the interior.

The short version is you can get some relief with increasing the extrusion width, which decreases the amount of filament stretch. But getting as much cooling as you can directly on the areas that show it most is by far the best solution though.

[cambo3d]

is it a good idea to using cooling on abs, probably not because it warps but what about hot air, just hot enough to cool it, if that's makes sense.

do we just need to print slower.

[Polygonhell]

is it a good idea to using cooling on abs, probably not because it warps but what about hot air, just hot enough to cool it, if that's makes sense.

do we just need to print slower.

I run cooling on significant overhangs for ABS, but you have to print hot enough for the layers to bond and not delaminate. A good example is the belly of the tree frog, I find that virtually unprintable in ABS without some cooling.
For PLA you an never get enough cooling.

[cambo3d]

cooling with just a fan?

[aerouta]

Well, I'm a big fan of fans...

The two centered in the frame are printed with fans with a 0.5 nozzle. The one cutoff was printed without fans at 0.3 LH.

[Polygonhell]

cooling with just a fan?

Fan and I set a minimum layer time in the 20 second range.
On ABS I usually don't turn it on until after the first couple of layers and you have to be careful not to overly cool the bed when you do because the part will detatch.
As I said above you might have to increase the temperature slightly to stop the part delaminating, but the net effect is it reaches the plastic transition point faster.
Once it's there ~100C it's not curling anywhere.