SLS requires no supports (powder bed self-supporting); DMLS requires critical metal supports for heat dissipation and part anchoring.
SLS uses a powder bed that encases the part entirely, providing mechanical support from all directions. No dedicated support geometry is needed: any overhang, internal channel, or complex curve is achievable without penalty. DMLS melts metal at very high temperatures; without solid support structures the part warps, lifts from the platform, or cracks due to thermal gradients. Supports also conduct heat away from the melt pool.
For SLS orient for best surface finish and pack density: supports are irrelevant. For DMLS minimise support volume and attachment area: orient overhangs to self-support under 45°, use conical supports instead of block supports, and plan all support access for CNC or EDM removal before final machining.
SLS: avoid fully closed internal cavities: the entrapped powder cannot be removed. DMLS: underestimating support volume inflates material and machining cost. Remove supports before stress relief to avoid cracking at attachment points.
Related terms: Self-supporting design (minimising supports), Build orientation decision, Residual stress and stress relief (DMLS)
| Theme | orientation |
|---|---|
| SLS | None None None: No supports needed, the powder bed is self-supporting, full geometric freedom. |
| DMLS | None None None: CRITICAL, required for heat dissipation and anchoring, removal requires CNC/EDM post-processing. |
| Also called | support structures, sacrificial supports, powder bed self-support |
| Source | tech/dmls.md, materials/titanium-ti6al4v.md |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert