A portion of a print extending beyond the layer below, unsupported by material underneath.
In FDM each layer deposits on the layer below. When a layer extends outward at an angle it partially hangs in air. The critical overhang angle is measured from the vertical Z-axis: most FDM printers print reliably up to 45 degrees from vertical without supports. Beyond this, insufficient support area causes sagging, curling, and surface defects.
Design parts to keep overhangs within 45 degrees from vertical. Use chamfers instead of horizontal ledges. Enable supports in the slicer for angles beyond the machine limit. Slow overhang speed to 25-40 mm/s and increase cooling fan to 100% on overhang perimeters to reduce sag.
Printing steep overhangs without supports produces stringy rough undersurfaces. Too-aggressive fan cooling on overhangs may delaminate adjacent layers. Supports too dense are difficult to remove; calibrate support interface distance carefully (0.2-0.3 mm for PLA).
Related terms: Supports, Part Cooling, Bridging
| Field | 3D printing, 3D design |
|---|---|
| Also called | overhang angle |
| Source | EDi Brain: tech/fdm |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert