Overhangs

Although it is recommended to use support for overhang angle, it usually saves time and material to being able to print high quality overhang surfaces.

The challenge when printing overhang surfaces is the amount of actual unsupported area. As you can see below the same angle can give different unsupported area depending on the layer height. It can appear that the smaller the unsupported area the better, however the smaller the layer height the less rigid the unsupported area will be. It will always be a balance between rigidity and amount of unsupported area.

Different factor can affect the overhang surfaces. As represented on the graphic below two main forces will be applied on the unsupported area: its weight (F1) and the polymer stress (F2).

The main factors affecting theses forces is summarized above, however generally speaking the best overhang surfaces will be given with a high layer height (more rigidity), low printing speed (more consistent extrusion) and high extrusion rate (more consistent extrusion).