Designing geometry that eliminates or radically reduces the need for support structures through chamfers, teardrop holes, and bridging: cutting print time and post-processing.
Every support structure adds material cost, increases post-processing time, leaves a surface scar, and risks damaging the part during removal. Self-supporting geometry relies on three rules: (1) overhangs ≤ 45° from vertical are self-supporting in FDM (≤ 30° in SLA/DMLS); (2) horizontal holes should be teardrop-shaped so the top portion stays within the self-support angle; (3) bridges up to 10 mm (FDM) or 5 mm (SLA) require no support.
Replace horizontal round holes with teardrop profiles. Add 45° chamfers to the underside of horizontal ledges. Split complex parts into two halves at a natural parting line and bond after printing. Redesign downward-facing flat surfaces to curved or angled forms. For SLS, these rules can be relaxed entirely: exploit the freedom with internal channels, lattices, and organic shapes.
Over-chamfering weakens structural cross-sections. Teardrop holes must be reamed or drilled if tight tolerances are needed. Bridges over 10 mm will sag in FDM: verify with a test print before committing to production.
Related terms: Build orientation decision, Support strategy (SLS vs DMLS), Warping and first-layer adhesion
| Theme | orientation |
|---|---|
| Also called | supportless design, overhang elimination, 45-degree rule |
| Source | tech/fdm-fff.md, sources/2026-04/2026-04-24--3d-printing-best-practices-guide, sources/2026-04/2026-04-30--fdm-starterpack-bg |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert