When a part needs to be strong, geometrically complex, and produced in small batches without the cost of tooling, SLS 3D printing is often the right process. It produces durable nylon parts with no support structures, full design freedom, and mechanical properties good enough for end-use components — not just prototypes. This guide covers how SLS works, what it costs, when to choose it, and how to find a vetted service bureau.
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How SLS Works
Selective Laser Sintering builds parts from a bed of fine polymer powder. A laser traces each layer's cross-section, fusing the powder where the part is solid; the build platform drops, a fresh layer of powder is spread, and the process repeats. The unfused powder surrounding the part acts as its own support.
That single fact — self-supporting powder — is what makes SLS different. There are no support structures to design around, no support scars to remove, and no geometry that's "unprintable" because it overhangs. You can nest parts in three dimensions and fill the chamber, which is why SLS scales efficiently to small production runs.
Why Engineers Choose SLS
Strength and isotropy. SLS nylon parts are strong in all directions, unlike FDM parts that are weaker between layers. That makes SLS suitable for functional testing and end-use parts that take real load.
Design freedom. Snap fits, living hinges, captive components, lattices, and complex internal channels print in a single run. Assemblies that would require multiple FDM parts can become one SLS part.
Batch economics. Because parts nest in the powder bed, the cost per part falls as quantity rises. For 10–100 durable nylon parts, SLS frequently beats both FDM (on strength and finish) and injection molding (on tooling cost and lead time).
Consistent finish. Every face comes out with the same matte texture — no support-side roughness to clean up.
SLS vs FDM vs Metal — A Quick Comparison
| Factor | SLS (nylon) | FDM | Metal (DMLS) |
|---|---|---|---|
| Part strength | High, isotropic | Moderate, weaker between layers | Highest |
| Geometry freedom | Excellent (no supports) | Limited by overhangs | Good (needs supports) |
| Surface finish | Uniform matte | Visible layer lines | Rough, needs machining |
| Typical cost/part | $30–500 | $20–300 | $400+ |
| Best for | Functional nylon parts, small runs | Cheap prototypes, large parts | Metal-grade, certified work |
| Lead time | 5–7 days | 2–5 days | 2–4 weeks |
For a deeper look at the metal option, see our metal 3D printing services guide. If your run is larger and repeatable, our low-volume 3D printing services overview covers the bridge between prototyping and production.
What SLS Costs
SLS pricing is driven by two things: the volume of the part (material consumed) and how efficiently parts nest in the build. Rough ranges:
- Small functional parts: $30–150 each
- Mid-size parts: $150–500 each
- Batches of 10–100: quoted by total volume, with per-part cost dropping as the chamber fills
For a single one-off, FDM is usually cheaper. The moment you need strength, complex geometry, or a batch of durable parts, SLS economics pull ahead.
How to Choose an SLS Service Bureau
Confirm SLS Is In-House
Many shops advertise SLS but subcontract it. In-house SLS means better control over lead time, finishing, and quality. Ask directly, and ask what machines and materials they run.
Match the Material to the Application
Standard PA 12 covers most work. Specify PA 11 for impact and flex, glass-filled nylon for stiffness and heat, or a flame-retardant/ESD grade for electronics and transit. Our guide to choosing a 3D printing service walks through the broader vetting checklist.
Specify Finishing Up Front
Decide whether you need media tumbling, dyeing, vapor smoothing, or bead blasting before quoting — finishing affects both cost and lead time. If specific features need tight tolerances, call them out on the drawing.
Send the Right Files
SLS bureaus typically want a watertight STL or a STEP file. If you're unsure which to send, our STL vs STEP files guide explains the difference.
When SLS Isn't the Answer
SLS is excellent for nylon, but it isn't universal. For the highest detail and smoothest cosmetic surface, SLA resin wins — see SLA vs FDM printing. For metal-grade strength, heat resistance, or certified components, you need metal printing. And for a quick, cheap concept check before committing to an SLS run, a desktop FDM printer like Anycubic's desktop lineup is often enough to validate fit before you order production-grade nylon.
Order SLS Parts from a Vetted Provider
Browse the 3D Prototyping Hub directory and request a quote. Filter for the technology and materials you need, send your files, and get direct quotes from verified SLS providers. No account required.