Glass-Bead-Filled Polyamide 12 (PA12 GF)

Material Profile: Glass-Bead-Filled Polyamide 12 (PA12 GF) for Selective Laser Sintering

SLS Engineering Material Technical Report Series

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—Glass-bead-filled PA12 (PA12 GF, EOS PA 3200 GF) is the standard glass-reinforced SLS thermoplastic. The matrix is the same precipitation-polymerised PA12 used in EOS PA 2200, mechanically pre-blended with ≈ 40 wt% (≈ 25 vol%) of solid soda-lime borosilicate glass beads of typical diameter 30 µm. Compared to unfilled PA12, the glass beads roughly double the tensile modulus (3 200 vs 1 650 MPa) and raise HDT @ 1.82 MPa from 84 °C to 96 °C, at the cost of reduced elongation at break (≈ 9 % vs 18 %) and increased part density (1.22 vs 0.93 g/cm³). The use of spherical beads (rather than chopped fibers) avoids the directional alignment that would compound SLS layer anisotropy, so the resulting composite is closer to isotropic than fiber-filled alternatives. PA12 GF is the workhorse for stiff, dimensionally stable housings, fixtures, and under-hood automotive components requiring intermediate temperature performance.

Index Terms—additive manufacturing, selective laser sintering, SLS, glass-filled polyamide, PA12 GF, PA 3200 GF, glass beads, composite.

I.  MATERIAL IDENTIFICATION

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

A.  Designation

Trade names: EOS PA 3200 GF (the original and dominant grade); Stratasys / 3D Systems DuraForm GF; HP 3D High Reusability PA12 GB; Sinterit Polypropylene-glass blends are NOT equivalent (different matrix). Composition and bead loading are similar across vendors at ~30–40 wt% glass.

B.  Full Chemical Name

PA12 matrix (poly(laurolactam)) mechanically pre-blended with solid soda-lime borosilicate glass microspheres. The matrix repeat unit chemistry is identical to PA 2200; the reinforcement is non-reactive (no chemical bond between matrix and bead surface) — load transfer is purely through mechanical (shear and friction) coupling at the matrix-bead interface, occasionally enhanced by silane sizing.

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Matrix: -[NH-(CH₂)₁₁-CO]-_n. Reinforcement: solid spherical SiO₂-Na₂O-CaO glass beads, d ≈ 30 µm, density ≈ 2.5 g/cm³. Composite repeat unit is not chemically defined — it is a particulate composite, not a copolymer.

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

Fig. 2.  Schematic of dispersed reinforcement / filler in the polymer matrix (not to scale).

B.  Composition Breakdown

TABLE I
 COMPOSITIONAL BREAKDOWN OF PA12 GF (GLASS-BEAD-FILLED PA12, EOS PA 3200 GF) (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 GF (GLASS-BEAD-FILLED PA12, EOS PA 3200 GF))

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 GF (GLASS-BEAD-FILLED PA12, EOS PA 3200 GF))

Spherical glass beads (vs aligned fibers) yield modest XY-Z anisotropy compared to fiber-reinforced FDM. Z-direction modulus drops to ~78 % of XY because the glass-PA12 interface bears load less effectively across an inter-layer fusion plane. Anisotropy can be reduced further by orienting parts so primary load axes lie in-plane; for axisymmetric parts this is automatic.

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 GF (GLASS-BEAD-FILLED PA12, EOS PA 3200 GF)

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: ≈ 41 °C (matrix value; unchanged from neat PA12).

Glass beads do not shift the matrix Tg measurably. The improved temperature performance (HDT @ 1.82 MPa raised to 96 °C) comes from the suppression of macroscopic creep by the rigid bead network, not from a higher Tg.

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 GF (GLASS-BEAD-FILLED PA12, EOS PA 3200 GF) UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Stiffness with isotropy

Tensile modulus ≈ 3 200 MPa is roughly double neat PA12. Because the reinforcement is spherical, mechanical properties are far more isotropic than fiber-reinforced grades — there is no preferred fiber alignment to track during build orientation planning. This makes PA12 GF the SLS material of first choice for housings and brackets where orientation flexibility matters.

B.  Improved temperature performance

HDT @ 1.82 MPa rises to 96 °C, allowing intermittent under-hood automotive duty up to ~80 °C continuous and 120 °C peak. Continuous-service rating is limited by matrix creep, not by glass content — for higher temperatures, carbon-fiber-filled or PEEK-based grades are preferred.

C.  Wear resistance and dimensional stability

Glass beads improve abrasive wear performance by ~50 % vs neat PA12 and provide best-in-class dimensional stability (≤ ±0.2 % across large flat geometries) — relevant for jigs, fixtures, and CMM inspection mounts.

D.  Higher cost and machine wear

Glass beads abrade conveying screws, sieves, and cabinet seals at higher rates than neat PA12. Material cost per kg is ~30–50 % higher than PA 2200. For these reasons, PA12 GF is reserved for parts whose stiffness or temperature requirement justifies the premium.

E.  Smooth surface and accurate fine features

EOS PA 3200 GF datasheet specifically notes 'very smooth surfaces and high accuracy' compared to neat PA12 — the glass beads constrain matrix shrinkage during cooling, giving parts that hold tight tolerances down to ~0.5 mm wall thickness.

IX.  REPRESENTATIVE APPLICATIONS

PA12 GF (Glass-bead-filled PA12, EOS PA 3200 GF) is typically deployed in the following applications:

1)  Engineering housings under thermal load: Electronic enclosures and sensor housings exposed to elevated cabinet temperatures (40–80 °C continuous), where neat PA12 would soften.

2)  Jigs, fixtures and tooling: CMM (coordinate-measuring-machine) fixtures, drilling templates, assembly jigs — high stiffness and dimensional stability replace machined aluminium at a fraction of the cost and lead time.

3)  Automotive under-hood components: Air ducts, turbocharger ancillaries, and sensor brackets in the warm engine bay where temperature peaks below 120 °C are tolerated.

4)  Industrial machinery covers and panels: Lightweight (0.93 vs 7.85 g/cm³ for steel) replacements for sheet-metal cabinet sections, especially in food-handling lines where the glass content is non-shedding (vs fiber composites).

5)  Wind-tunnel and motor sport models: Stiff, dimensionally stable scale-model parts whose detail features must hold tight tolerances during repeated handling and instrumentation.

X.  REFERENCES

[1]  EOS GmbH, “PA 3200 GF — Material data sheet,” EOS Polymer Solutions, 2024. [Online]. Available: https://www.eos.info/polymer-solutions/polymer-materials/data-sheets/mds-pa-3200-gf

[2]  EOS GmbH, “Material Data Sheet — PA 3200 GF Glass-filled Fine Polyamide,” AHO/12.08. [Online]. Available: https://www.3d-prototip.si/files/material-pa-3200gf.pdf

[3]  Forge Labs, “Glass-Filled Nylon PA12 — Material reference,” 2025. [Online]. Available: https://forgelabs.com/3d-printing/materials/glass-filled-nylon

[4]  MatWeb, “EOS PA 3200 GF Nylon 12, Glass Bead Filled,” MatWeb LLC. [Online]. Available: https://www.matweb.com/search/datasheettext.aspx?matguid=e80def5d962e43e6b9f88134f881f203

[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. Schmid et al., “Multi-scale modelling and analysis of laser-sintered PA12 glass-bead composites,” Additive Manufacturing, vol. 24, pp. 547–558, 2018.

(Image Resouce : Weerg)