Materials for SLS: guide

In Selective Laser Sintering (SLS), material selection plays a decisive role in determining not just print quality, but also part performance, durability, finish, and compliance. SLS is unique among additive manufacturing methods in that it uses powdered thermoplastics, often with engineered additives, to produce functional parts without supports. As a powder bed fusion (PBF) technology, SLS relies on controlled thermal gradients and precise powder behavior, which makes material selection critical for print repeatability and mechanical properties. This opens the door to a range of materials optimized for everything from flexibility to high temperature resistance.

Below, you’ll find a comprehensive comparison of key materials used in SLS 3D printing, including common polymers, flexible options, and performance-grade powders. This table is designed to help engineers, designers, and production teams quickly evaluate the trade-offs and advantages of each.

SLS materials comparison table

MaterialDescription & propertiesKey applicationsProsLimitations
PA12 (Nylon 12)Engineering-grade thermoplastic with excellent mechanical strength and chemical resistanceFunctional parts, housings, jigs, prototypesTough, dimensionally stable, good ageing stability (moderate UV resistance)Limited flexibility, brittle under certain loads
PA11Bio-based nylon from castor oil, offers better impact resistance and flexibility than PA12Sporting goods, orthotics, automotiveRenewable, ductile, high elongationSlightly higher cost, absorbs more moisture than PA12
TPUFlexible polyurethane elastomer, ideal for producing soft, rubber-like partsGaskets, wearables, shock absorbersElastic, wear-resistant, impact-absorbingRequires fine-tuned parameters, limited surface detail; mechanical behavior is highly dependent on wall thickness, which limits ultra-thin features
PP (Polypropylene)Lightweight, chemically inert, and fatigue-resistantContainers, chemical applications, living hingesLow density, excellent chemical resistanceWarping risks, weaker interlayer bonding compared to PA materials
PA12 CFCarbon fiber–filled PA12 offering high stiffness and reduced weightStructural parts, brackets, load-bearing componentsLightweight, rigid, thermally stableMore brittle, highly abrasive to recoaters and internal hardware
PA11 ESDElectrostatic dissipative PA11, used in electronics and ATEX environmentsElectronics housings, ESD-safe partsResistivity typically falls within the 10⁶–10⁹ Ω range, suitable for EPA/ESD environmentsNiche application, higher cost
PA12 SmoothPA12 variant optimized for smooth surface finishesDesign models, final-use parts with visual appealGreat finish straight from printerSimilar mechanical profile to standard PA12
Flexible PAA modified nylon offering limited flexibility compared to TPU but stronger than elastomersSemi-rigid parts, snaps, clipsBalance between stiffness and flexibilityNot fully elastic, application-specific
Glass-Filled PA12Reinforced with glass fibers for enhanced dimensional stabilityPrecision mechanical parts, enclosuresHigh stiffness, thermal stability; improved dimensional accuracy under loadMore brittle, increased machine wear due to glass fiber abrasiveness
DOWNLOAD COMPARISON TABLE (PDF)

Notes on powder handling and refresh rates

Each SLS powder behaves differently in terms of refresh rate — the proportion of new powder that must be mixed with used material from a previous print. For example:

PA12 and PA11 typically allow for high reuse rates (up to 70–80%) with minimal degradation,

TPU may require more frequent powder replacement due to its hygroscopic nature,

reinforced or specialty powders often need tighter process control and lower reuse percentages to ensure consistency. TPU also tends to clump if stored improperly, which can impair recoating and cause surface defects.

Proper storage, sieving, and thermal consistency are key to maintaining performance over multiple cycles.

Choosing based on application

While material properties are important, the intended use case should drive selection. For instance:

  • glass-filled variants are great for stability, but not where impact resistance is crucial.
  • if you need snap-fit parts or thin-walled flexibility, PA11 or TPU are better suited,
  • for aesthetic surfaces with minimal post-processing, go for PA12 Smooth,
  • if your goal is mechanical strength with weight reduction, carbon-fiber-filled PA12 is ideal; for maximum stiffness rather than impact strength, glass-filled PA12 may be preferable,

Conclusion

There is no one-size-fits-all material in SLS printing — the ideal powder depends on a balance of mechanical requirements, surface finish, compliance, and cost. This guide should serve as a quick-reference framework for material selection in any SLS workflow, whether for prototyping, small batch production, or functional end-use parts.

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