Negative angle printing is not smooth

[Boris]

Hello guys.

There is another question about quality

Here, on a picture you may see legs printed without supports with ABS(I dont think supports bring any difference in that case).
As you see, the positive angle, outside of legs printed very well. But negative side is very ...steppy
Well, is there any way to smooth things like that ?
I can't rotate the model for many reasons

[fesch]

I have the same problem and would be really happy about a tip on how this could be avoided.

Most of the time I can turn my prints in some other way so that I don't need to print negative angles, but this is not always possible.

[fesch]

I'll answer my own question, at least partially: Today I've added an additional fan near the extruder. This reduces the distortions on the printed negative angles. Maybe I'll have to move it closer to eliminate them totally ?

[frankjoke]

Strange, on ABS I would not use fan at all!

Anyhow, which slicer do you use? How many perimeters (solid outside lines) and do you print them inside out or outside in?

I use 3 perimeters on Kisslicer from inside to have best coverage of such angles.

On top print speed and material matters as well because it flows down easily without any support.

[satoer]

With large overhangs you get a better quality if you print the inner Perimeters first.

This was sliced with Slic3r, it's halve a inner sphere and printed upside down. The layers near the middle are almost horizontal and still printed perfectly. (used a layer height 0,2mm with a speed of 150%)

[frankjoke]

satoer,

this is a very big print where every loop takes pretty long. On such small prints for the legs the material has not a lot of time to bind and cool and it's then too hot on the next perimeter and 'rinning' down.