Minimum gap between two printed surfaces that must slide, rotate, or snap together without fusing during printing.
Clearance is the intentional gap between two mating printed surfaces. Each AM technology leaves residue, excess material, sintered powder, resin film, that effectively reduces gaps. The clearance rule defines the floor below which parts either fuse or bind.
For FDM snap-fit hinges use 0.3 mm. For SLA precision bearings 0.15 mm is workable. For SLS in-situ assemblies (printed-in-place joints) use 0.5 mm so powder flushes cleanly. DMLS mating faces often need secondary finish machining.
Printing at 0° (XY plane) tightens clearance; vertical (Z) orientation loosens it due to layer stacking. Always test-print a fit coupon before committing to a full assembly. In SLA, parts without clearance cure-bond to the resin tank at contact points.
Related terms: Dimensional tolerance, Press-fit joint, Snap-fit design
| Theme | assembly |
|---|---|
| FDM | >= 0.2 mm: 0.2–0.4 mm minimum; below 0.2 mm parts fuse during print. |
| SLA | >= 0.1 mm: 0.1 mm achievable due to high resolution; precise. |
| SLS | >= 0.4 mm: 0.4–0.6 mm; unfused powder between parts must be able to escape. |
| DMLS | >= 0.5 mm: 0.5 mm minimum plus powder removal access. |
| Also called | fit clearance, assembly gap |
| Source | 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