How to improve overhangs in 3D printing
In an overhang, each new layer extends partly beyond the previous one. As that offset increases, less material is supported by the layer below. The maximum printable angle depends on the printer, nozzle, material, cooling, layer height and geometry.
There is no universal 45° limit
The familiar 45-degree rule is a useful rough guideline, not a physical limit. Prusa notes that clean overhangs can vary roughly between 45 and 60 degrees depending on machine and settings, with some newer cooling systems capable of more. Test your own printer and material.
Layer height
Smaller layers can reduce the horizontal step per layer. That can improve overhang geometry, but increases print time.
Cooling
More cooling often helps PLA overhangs. Too much cooling on ASA or ABS can create other problems.
Improve the geometry
Instead of a 90° underside, consider:
- chamfer
- curve
- stepped transition
Keep important surfaces away from support
A surface printed directly above support often looks different from a normal side wall. Avoid placing critical mating surfaces there where possible.