Inframotion 3D explains what to check before buying PA11 powder for SLS

Inframotion 3D has published two buyer guides on PA11 (Nylon 11) powder for selective laser sintering. They stress that a datasheet is only a comparison point: the exact grade, the printer it runs on, powder reuse and storage decide whether parts perform as claimed.

Context Refresh ratio is the share of fresh powder mixed into recovered powder to form the next print-ready batch in an SLS build.

Why is PA11 chosen for SLS parts?

According to the guides, PA11 is picked when a part has to do real work: absorb impact, flex without cracking and resist oils, fuels and other media. Typical uses named are brackets, clips, housings, fluid-handling parts and replacement components, as well as functional prototypes. Chemically it is built from 11-aminoundecanoic acid and is commonly positioned as a bio-derived nylon, though the guides note that actual performance depends on the specific grade and a validated process.

The texts also compare it with PA12, the other established SLS nylon. They treat the choice as dependent on grade and system rather than a simple ranking, with PA11 favoured where ductile behaviour is decisive.

Which data should buyers verify?

The guides advise reviewing mechanical, thermal, physical and process-related data separately, and warn that grades, additives and filled variants are not interchangeable. Published values vary with build orientation and moisture state, so datasheets may list different figures for the XY plane and the Z direction, or for dry and conditioned samples. For design approval, the test condition should match the real application, and a single headline strength or elongation figure is rarely sufficient.

Powder behaviour counts as much as part data: particle size distribution, particle shape, additive package and moisture uptake affect feed, layer spreading and fusion consistency.

How do reuse, storage and machine fit affect results?

Not every PA11 grade can be dropped into any powder-bed machine. Each needs approval for the printer, its parameter set and handling routine, and some materials also depend on a controlled atmosphere such as inert gas. Refresh ratio, the share of fresh powder added to recovered powder, is grade-specific and printer-specific and should come from validated guidance. Branded materials such as PA11 Onyx may have their own rules that do not carry over to other PA11 powders.

Powder should be kept in sealed, dry containers with limited exposure and traceable batch control. Recovered powder needs sieving before reuse, and airborne dust should be controlled with approved industrial vacuum equipment.

What it means

For small and mid sized manufacturers adopting SLS, the practical point is that PA11 cost per part depends on powder reuse as much as on the price per kilogram. Refresh ratio, storage discipline and grade approval for the specific machine need to be fixed and documented before any end-use part is promised to a customer. Datasheet values from different suppliers are not directly comparable, so qualification should rest on parts printed in the intended orientation and condition. Note that the source is a supplier's buyer guide, not independent test data.

Frequently asked questions

Can any PA11 powder be used in any SLS printer?

No. A specific grade needs approval for the printer platform, parameter set and handling routine, and some also need a controlled atmosphere.

Do PA11 properties change with orientation and moisture?

Yes. Results vary with build orientation and moisture state, so datasheets may list separate XY and Z or dry and conditioned values, and the matching test condition should be used for design approval.

What is the refresh ratio in PA11 printing?

It is the proportion of fresh powder added to recovered powder to make the next print-ready batch. The right value is specific to the grade and printer.