Polyamide 12 (PA12)

Material Profile: Polyamide 12 (PA12) for Selective Laser Sintering

SLS Engineering Material Technical Report Series

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—Polyamide 12 (PA12, Nylon 12, EOS PA 2200) is the most widely used semi-crystalline thermoplastic powder for selective laser sintering (SLS). It combines a balanced mechanical property profile, excellent chemical resistance, low water absorption (< 1.5 wt%), biocompatibility (USP Class VI / ISO 10993-1) and food-contact compliance (EU 2002/72/EC) with high process stability. PA12 is supplied as a fine white powder of typical particle diameter 50–60 µm produced by precipitation polymerisation; it is consolidated in a CO₂-laser SLS machine at a powder-bed temperature of approximately 170 °C — held in the unusually wide ~25 °C 'sintering window' between recrystallisation and melting. This profile summarises composition, anisotropic mechanical performance, recommended SLS process parameters, glass-transition and heat-deflection temperatures, distinguishing characteristics, and representative applications.

Index Terms—additive manufacturing, selective laser sintering, SLS, polyamide 12, PA12, PA 2200, nylon 12, polymer powder.

I.  MATERIAL IDENTIFICATION

This section establishes the canonical names and commercial designations under which the material is supplied.

A.  Designation

Trade names: EOS PA 2200 (Balance / Performance / Speed / Top Quality / Top Speed); Stratasys / 3D Systems DuraForm PA; HP 3D High Reusability PA12; BASF Ultrasint PA6000; Evonik VESTOSINT 3D powders. All are based on Polyamide 12 with stabiliser packages tuned for laser-sintering.

B.  Full Chemical Name

Polyamide 12, also written as poly(laurolactam) or poly(ω-aminolauric acid). It is a semi-crystalline aliphatic polyamide produced by ring-opening polymerisation of laurolactam (a 12-membered lactam). The 12 in the name denotes the number of carbon atoms in the repeating unit between successive amide groups.

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Repeat unit: -[NH-(CH₂)₁₁-CO]-_n. Empirical molecular formula of the repeat unit: C₁₂H₂₃NO. Each repeat contributes one amide (-CO-NH-) hydrogen-bonding site and an 11-CH₂ aliphatic spacer.

Fig. 1.  Repeating unit / structural schematic of the polymer matrix.

Fig. 2.  Schematic of the single-phase polymer (no reinforcement).

B.  Composition Breakdown

TABLE I
 COMPOSITIONAL BREAKDOWN OF PA12 (NYLON 12, EOS PA 2200) (TYPICAL / PER SUPPLIER DATASHEET)

III.  MECHANICAL PROPERTIES — XY BUILD DIRECTION (HORIZONTAL)

In the XY orientation the tensile load is applied parallel to the powder-bed plane (in-plane). For polymer SLS this is typically the stronger orientation due to better neck formation between particles within a single layer; for metal DMLS/SLM, columnar β / α-grain growth perpendicular to the build direction also yields different anisotropy that is partially relieved by post-build heat treatment (e.g. stress-relief, HIP).

TABLE II
 MECHANICAL PROPERTIES — XY ORIENTATION (PA12 (NYLON 12, EOS PA 2200))

IV.  MECHANICAL PROPERTIES — Z BUILD DIRECTION (VERTICAL)

In the Z orientation the tensile load is applied perpendicular to the powder layers; failure occurs across inter-layer fusion bonds. For polymer SLS the Z properties are typically 70–90 % of XY; for metal LPBF (laser powder-bed fusion) processes Z elongation is often higher due to the columnar grain structure but UTS / yield can be slightly lower in the as-built state. Heat treatment (anneal, HIP) reduces the anisotropy substantially.

TABLE III
 MECHANICAL PROPERTIES — Z ORIENTATION (PA12 (NYLON 12, EOS PA 2200))

PA12 SLS parts have lower anisotropy than fibre-reinforced FDM filaments, but Z-direction elongation is markedly lower (~4 %) than XY (~18 %) because failure propagates along the inter-layer fusion plane. Increasing energy density (higher laser power, slower scan) improves Z-direction strength at some cost in part dimensional accuracy.

V.  RECOMMENDED PROCESS PARAMETERS

Values summarised below give consensus operating windows from public datasheets (EOS, 3D Systems, BASF Forward AM, SLM Solutions). Specific machines and parameter sets may differ within ±10 %; the supplier's verified parameter sheet always supersedes this table.

TABLE IV
 RECOMMENDED LASER POWDER-BED-FUSION PROCESS PARAMETERS FOR PA12 (NYLON 12, EOS PA 2200)

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: ≈ 41 °C.

Tg measured by DSC; storage-modulus inflection per DMA torsion is ~50 °C. Above Tg the amorphous phase softens but the 25–30 % crystalline phase preserves dimensional stability up to the HDT @ 0.45 MPa of ~150 °C.

VII.  HEAT DEFLECTION TEMPERATURE (HDT)

Heat deflection temperature is the temperature at which a standard bar deflects 0.25 mm under a specified flexural load (ASTM D648 / ISO 75).

TABLE V
 HEAT DEFLECTION TEMPERATURE OF PA12 (NYLON 12, EOS PA 2200) UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Biocompatibility & food contact

EOS PA 2200 is certified biocompatible per EN ISO 10993-1 and USP Class VI / 121 °C, and complies with EU Plastic Directive 2002/72/EC for food contact (with the exception of strongly alcoholic beverages). This makes PA12 unique among general-purpose SLS materials for direct medical and food-handling applications.

B.  Chemical resistance

Excellent resistance to most aliphatic and aromatic hydrocarbons (oil, fuel, hydraulic fluids), aldehydes, ketones, mineral bases and salts. Limited resistance to strong acids, phenols and chlorinated solvents. Water absorption at 23 °C / 50 % RH is < 1.5 wt%, far lower than PA6 or PA66 (3–8 wt%), which keeps mechanical properties stable in humid environments.

C.  Reusability and powder economy

Unsintered PA12 powder can be reused. Standard practice is to mix used and virgin powder at 50:50 (or sometimes 70:30 used:virgin); EOS PA 2200 datasheet recommends adapting the refresh ratio to keep MFR within process specification. Failure to refresh produces 'orange-peel' surface defects.

D.  Flame behaviour

PA12 contains no flame retardants and burns readily once ignited; UL 94 rating without modification is HB. Flame-retardant variants such as EOS PA 2210 FR or PA 2241 FR (mineral / ammonium-polyphosphate filled) achieve UL 94 V-0 at 1.5 mm and pass FAR 25.853(a) Appendix F vertical and horizontal burn tests for aircraft cabin interiors. Combustion of unmodified PA12 above 350 °C generates CO, CO₂, H₂O and trace nitrogen-containing volatiles.

E.  Process window — wide and stable

PA12 has a wide 'sintering window' (~25 °C) between recrystallisation and melting endotherms, the largest of any commercial SLS polymer. This is why PA12 has dominated SLS for 30+ years — the wide window forgives small temperature gradients across the build platform.

IX.  REPRESENTATIVE APPLICATIONS

PA12 (Nylon 12, EOS PA 2200) is typically deployed in the following applications:

1)  Functional prototypes: Form-, fit- and function-testing of injection-moulded parts before tooling commitment, leveraging PA12's near-injection-moulded mechanical performance and 0.10 mm layer resolution.

2)  End-use mass-customised parts: Hearing-aid shells, dental aligner moulds, custom orthotics, and eyewear frames — high-volume series production using bins of multiple unique geometries.

3)  Lightweight ducts & manifolds: Thin-wall (≥ 0.7 mm) air ducts and hydraulic manifolds in motorsport and unmanned-aerial-vehicle applications, exploiting PA12's chemical resistance and low density (0.93 g/cm³).

4)  Living hinges and snap-fit assemblies: PA12's 18 % elongation at break supports thin-section integral hinges and one-shot deployable mechanisms in consumer products.

5)  Medical-grade single-use devices: Sterilizable surgical guides, anatomical models for pre-operative planning, and patient-specific cutting jigs — all leveraging the USP Class VI biocompatibility certification.

X.  REFERENCES

[1]  EOS GmbH, “PA 2200 Polyamide 12 — Material data sheet,” EOS Polymer Solutions, Krailling, Germany, 2024. [Online]. Available: https://www.eos.info/polymer-solutions/polymer-materials/data-sheets/mds-pa-2200

[2]  EOS GmbH, “Product Information PA 2200 (PA12),” EOS Polymer Solutions Technical Bulletin, AHO/03.10. [Online]. Available: https://3dformtech.fi/wp-content/uploads/2019/11/Material-Data-PA2200.pdf

[3]  Sculpteo, “Nylon PA12 — Technical specifications,” Sculpteo Materials Reference. [Online]. Available: https://www.sculpteo.com/en/materials/sls-material/plastic-material/

[4]  Formlabs, “Guide to Selective Laser Sintering (SLS) 3D Printing,” Formlabs Whitepaper, 2023. [Online]. Available: https://formlabs.com/blog/what-is-selective-laser-sintering/

[5]  ASTM D638-14, “Standard Test Method for Tensile Properties of Plastics,” ASTM International, West Conshohocken, PA, 2014.

[6]  ASTM D790-17, “Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics,” ASTM International, 2017.

[7]  ASTM D256-10, “Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics,” ASTM International, 2018.

[8]  ASTM D648-18, “Standard Test Method for Deflection Temperature of Plastics Under Flexural Load,” ASTM International, 2018.

[9]  ISO 527-2:2012, “Plastics — Determination of tensile properties — Part 2,” ISO, Geneva, 2012.

[10]  ASTM D2240-15, “Standard Test Method for Rubber Property — Durometer Hardness,” ASTM International, 2015.

[11]  B. Caulfield, P. E. McHugh, S. Lohfeld, “Dependence of mechanical properties of polyamide components on build parameters in the SLS process,” J. Mater. Process. Technol., vol. 182, pp. 477–488, 2007.

(Image Resouce : Weerg)