§ 01 / WHY

Why SLS over SLA or FDM

SLS occupies a specific sweet spot in additive manufacturing: functional parts, true mechanical performance, zero supports.

No supports means complete design freedom. Internal channels, nested assemblies, lattice structures, thin flexing sections — all print in a single pass without the design compromises support material forces onto SLA and FDM.

Nylon 12 (PA12), the workhorse SLS material, is a real engineering plastic — not a design-review resin. Parts survive real-world loads, snap-fit thousands of cycles without fatigue, withstand 120 °C continuous service, and shrug off common chemicals.

The surface finish is the one compromise: grainy, like fine sandpaper. For cosmetic parts, you'll want to vibro-polish, bead-blast, or dye-coat. For functional parts hidden inside assemblies, the finish is fine as-is.

§ 02 / SLS

SLS materials

MaterialBest forTensileElongationHDT
PA12 (Nylon 12)General-purpose functional parts48 MPa18%163 °C
PA11 (Nylon 11)Higher impact, bio-based48 MPa45%182 °C
PA12-GF (Glass-filled)Stiff structural parts, fixtures51 MPa4%176 °C
PA12-CF (Carbon-filled)High strength-to-weight, aerospace70 MPa3%180 °C
PA12-AL (Alumide)Metallic look, thermal conduction48 MPa4%170 °C
PEBA (TPE powder)Rubber-like flexible parts8 MPa350%
PA12 FR (flame retardant)Aerospace interior, UL94 V-045 MPa10%170 °C
§ 03 / APPLICATIONS

Applications

End-use consumer partsSunglasses, custom eyewear, specialty footwear — SLS makes short runs viable.
Industrial end-effectorsRobot grippers, custom tool holders, vacuum cups — where each unit is unique.
Aerospace bracketsPA12-CF and PA12-FR for cabin components and non-critical brackets. FAA-compliant materials available.
Medical wearablesBraces, orthotics, prosthetic sockets — patient-specific fit from 3D scans.
Ducts & manifoldsComplex flow paths impossible to machine — printed in one piece, no assembly.
Bridge productionBetween prototype tooling and injection molding — 100–5,000 parts economically.
§ 04 / SLS

SLS design guidelines

01

Minimum wall: 0.8 mm

Below 0.8 mm walls can crack during powder extraction. 1.0 mm is safer for larger parts.

02

Trapped powder escape holes

Hollow parts need at least two Ø4 mm holes to vacuum out loose powder. Otherwise the part carries extra weight and contaminated powder stays inside.

03

Holes shrink slightly

SLS holes print about 0.2 mm undersized. For press-fit features, design 0.3 mm oversize or drill to final size post-print.

04

Living hinges work well

PA12 has excellent fatigue life. A 0.5 mm-thick hinge will survive thousands of flex cycles. Design hinge thickness ~0.5 mm × (part thickness / 3).

05

Nested & assembled in-printer

Print an assembly in one build — moving parts already assembled, no gluing. Leave 0.5 mm clearance between mating surfaces.

§ 05 / FAQ

FAQ

How does SLS compare to MJF?
Similar technology — both are powder-bed nylon processes. MJF (HP's Multi Jet Fusion) is faster, slightly tighter tolerances (±0.2 mm vs ±0.3 mm), and has a darker gray color. SLS runs more materials (flexible, flame retardant, alumide). We offer both — if volumes are low and you want PA12 in black or gray, MJF. If you need special materials or extreme geometries, SLS.
Can SLS parts be dyed?
Yes — SLS parts are commonly dyed black or other dark colors via hot-bath immersion. Only surface ~0.5 mm deep absorbs dye, so abrasion or machining can expose natural color below. For true-through-color, specify black PA12 from start.
Is SLS watertight?
Not out of the box — PA12 has micro-porosity between sintered grains. For waterproof parts, post-process options: impregnation (seals the porosity), vapor-smoothing (PA11/12 smoothing service), or coating. Add 3 days and $50+ per part for these.
Do you provide material certifications?
Yes. For PA12-FR (flame retardant aerospace grade) and biocompatible materials we provide full lot traceability, as-built density samples, and COA documentation. Budget 1 extra day for paperwork.
READY WHEN YOU ARE

SLS-ready parts in one week.

Upload STL. We orient to minimize powder-extraction cleanup of internal features, and print on calibrated EOS P396 machines.

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