Nylon PA12 in SLS: the material guide

If we had to pick a single material to cover 80% of industrial functional applications, it would be SLS-sintered Nylon PA12. It strikes the balance between mechanical performance, design freedom and cost, which is why it is the standard material for short runs in additive production. When parts grow in number or size, the same PA12 can also be printed with MJF.

What laser sintering of PA12 is

In SLS, a laser selectively sinters polyamide 12 powder, layer by layer, inside a powder bed that supports the part on its own: no support structures, so no removal marks and full design freedom. Dozens of parts are printed at once in the build chamber (nesting), and that is what drives down the unit cost of a batch.

The properties that matter

Tensile strength, elongation and HDT are the values in our materials catalog. HDT measures deflection under load in a short-term test: it is not the part's continuous service temperature.

The key figure is 85–90% isotropy: unlike FDM, which tops out at 70–80%, an SLS part is almost equally strong in every direction. You design it the way you would design an injection-molded part, without worrying much about layer orientation.

When to choose PA12 (and when not to)

Choose it for: short functional runs (10–500 parts), jigs, fixtures and robot grippers, housings and covers, snap-fits and living hinges, and prototypes that need testing under real loads.

Look elsewhere if you need continuous service above ~100 °C or extreme chemical environments (→ high-performance polymers), metal-like stiffness under directional loads (→ continuous fiber CFC), a part that has to stay metal (→ LPBF metal 3D printing), or a smooth, high-definition cosmetic finish (→ MSLA).

A note on sealing: as-built, the SLS surface is slightly porous. For fluid-tight or gas-tight parts we apply a sealing treatment (vapor smoothing, resin infiltration or painting).

SLS PA12 vs. FDM PA-CF: the most common question

Carbon-fiber nylon (PA-CF) in FDM is stiffer in the print plane and cheaper for a large one-off part; SLS PA12 wins on isotropy, complex geometry and batches. Rule of thumb: multidirectional loads or quantity → SLS; in-plane stiffness on a one-off → PA-CF. When a part sits on the boundary, we price both routes in the quote.

PA12 in SLS or in MJF?

SLS remains the route for prototypes and small batches; MJF PA12 pays off when the run gets larger or the part has to be leak-tight as printed. In practice:

• Size: SLS builds up to 330 × 330 × 565 mm, MJF up to 380 × 284 × 380 mm; the build volumes are comparable, so the part's envelope decides.
• Larger runs: MJF performs best when the parts fill its build volume in a single build.
• Tightness without treatment: MJF PA12 is dense and leak-tight, while SLS needs sealing.

The base polymer is the same, with 48 MPa tensile strength in both processes, so you can validate the design in SLS and move to MJF for production. Build volumes, materials and lead times for the two processes are compared side by side in MJF vs SLS: which to choose.

Tolerances and design

As-printed, expect ±0.3% (minimum ±0.3 mm) as typical; critical holes and fits are brought to tolerance with light finish machining. Recommended minimum wall thickness is ~1 mm, with embossed details from 0.5 mm. For the full picture, see Industrial 3D printing tolerances.

What we print it on

Our SLS department works with a build volume of up to 330 × 330 × 565 mm, with in-house powder management and a controlled refresh rate: repeatable quality from batch to batch. Pick your delivery tier: Express in 48–72 hours for urgent jobs, Rapid in 5 days for batches of up to 50 parts, or Economy in 7+ days at a reduced price. For MJF PA12, the lead time is stated in the quote.

Try the material on your part

Upload your CAD through the quote form: if PA12 is the right choice, we will confirm it within 24 working hours, along with the better-suited process, SLS or MJF. If it is not, we will propose the alternative with the best price-to-performance ratio.