The smallest printable wall thickness for each technology, below which walls fail to form reliably or lack structural integrity.
Wall thickness is governed by the deposition or curing resolution of each process. FDM extrudes beads of fixed width; two beads (perimeters) are the minimum for a mechanically coherent wall. SLA cures a layer area limited by spot size and resin viscosity. SLS and DMLS sinter/melt a powder bed: thinner walls risk incomplete fusion and post-process collapse.
Always align walls to multiples of nozzle diameter in FDM (e.g. 0.4 mm nozzle → 0.8 / 1.2 / 1.6 mm). For SLA hollowed dental or jewellery pieces, 0.5 mm shells are achievable but add drainage holes. For SLS functional parts target 1.0–2.0 mm. DMLS aerospace brackets typically use 0.8–1.5 mm walls with internal lattices to save mass.
Designing below the minimum results in missing walls in the slicer preview: catch this before printing. Walls that are exactly one nozzle-width wide in FDM have no overlap and delaminate under load. In DMLS, very thin walls distort due to thermal stress during build; always include stress-relief annealing.
Related terms: Overhang / Self-Supporting Angle, Minimum Hole Diameter, Fillets vs Sharp Internal Corners
| Theme | geometry |
|---|---|
| FDM | >= 0.8 mm: 0.8 mm equals two perimeters at a 0.4 mm nozzle. Below 0.4 mm walls are unreliable and prone to gaps. |
| SLA | >= 0.5 mm: 0.5 mm is the safe minimum for SLA resin; 0.3 mm is achievable only with high-density resins and vertical orientation. |
| SLS | >= 0.7 mm: 0.7 mm for PA12 sintering; 1.0 mm is recommended for structural parts to ensure reliable sintering and powder removal. |
| DMLS | >= 0.5 mm: 0.5 mm minimum for DMLS metal; 0.4 mm is possible only with fine lattice structures and optimised laser parameters. |
| Also called | shell thickness, wall width, perimeter thickness |
| Source | Wiki/tech/fdm-fff.md, Wiki/tech/sla.md, Wiki/tech/sls.md |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert