ASA (Acrylonitrile-Styrene-Acrylate) for FDM

Material Profile: ASA (Acrylonitrile-Styrene-Acrylate) for FDM

FDM Engineering Material Technical Report Series — Volume 8 of 16

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—ASA is a styrene-based terpolymer that replaces ABS's butadiene rubber phase with a saturated acrylate ester rubber. The saturated C–C backbone confers ~10× higher UV / weather resistance than ABS while preserving similar mechanical, thermal, and processing characteristics. ASA is the canonical FDM material for outdoor end-use parts, automotive exterior components, and any application requiring multi-year UV exposure.

Index Terms—additive manufacturing, FDM, ASA, UV resistance, weatherability, outdoor.

I.  MATERIAL IDENTIFICATION

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

A.  Designation

Trade name: ASA (generic; trademark-free). Stratasys, Polymaker, eSUN, Inslogic, and most filament suppliers offer ASA grades with similar performance windows.

B.  Full Chemical Name

Acrylonitrile-Styrene-Acrylate terpolymer. The acrylate ester rubber (typically n-butyl acrylate, BA) replaces the butadiene of ABS and is saturated, eliminating the C=C bonds that drive ABS's UV degradation.

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Idealised: [(C₃H₃N)ₐ-(C₇H₁₂O₂)ᵦ-(C₈H₈)ᵧ]ₙ where the middle block is poly(n-butyl acrylate). Composition typically 25/30/45 by mass (AN/Acrylate/Styrene).

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 ASA (TYPICAL / PER SUPPLIER DATASHEET)

III.  MECHANICAL PROPERTIES — XZ PRINT DIRECTION

In the XZ orientation the tensile load is applied parallel to the deposited rasters; for fibre-reinforced grades this is the strongest orientation because the fibres align preferentially along the extrusion direction.

TABLE II
 MECHANICAL PROPERTIES — XZ ORIENTATION (ASA)

IV.  MECHANICAL PROPERTIES — ZX PRINT DIRECTION

In the ZX orientation the tensile load is applied perpendicular to the print layers, so failure occurs through inter-layer (Z) bonds. Properties are markedly lower than in XZ — this anisotropy is intrinsic to FDM.

TABLE III
 MECHANICAL PROPERTIES — ZX ORIENTATION (ASA)

ASA anisotropy is similar to ABS (XZ:ZX UTS ≈ 1.4:1). The acrylate rubber phase actually improves interlayer adhesion slightly because the saturated rubber wets the polymer interface more effectively than butadiene during interlayer fusion.

V.  RECOMMENDED PRINT PARAMETERS

Values summarised below give consensus operating windows from public datasheets. Specific suppliers may differ within ±10 °C; the supplier datasheet always supersedes this table.

TABLE IV
 RECOMMENDED PRINT TEMPERATURE RANGES FOR ASA

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: ≈ 100 – 110 °C.

Tg is dominated by the styrene-acrylonitrile (SAN) phase. ASA can be acetone-vapour smoothed similarly to ABS, although less aggressively (the acrylate rubber phase resists acetone better than butadiene rubber).

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 ASA UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Outstanding UV / weather resistance

Filamentive reports ASA as 'ten times more weather resistant and UV-resistant than ABS', consistent with ASTM G155 / G154 accelerated weathering data showing minimal yellowing or property loss after 1000+ hours of UV exposure. The mechanism: ASA's acrylate ester rubber has saturated C–C bonds, eliminating the photo-oxidation pathway that degrades ABS's butadiene rubber.

B.  Standardised UV testing

Industry data on ASA weathering is typically generated per ASTM G154 (fluorescent UV chambers) or ASTM G155 (xenon-arc, more sun-like spectrum). ASA samples retain > 90% of original tensile strength after 1000 hours of cyclic UV + condensation per these standards.

C.  Mechanical performance

Tensile strength, modulus, and impact resistance are within 10% of standard ABS — substituting acrylate for butadiene rubber preserves the basic mechanical envelope while gaining UV stability.

D.  Limitations

Not flame-retardant; chemical attack by ketones, esters, and chlorinated solvents (similar to ABS); HDT limits service to ~80 °C continuous.

IX.  REPRESENTATIVE APPLICATIONS

ASA is typically deployed in the following applications:

1)  Outdoor signage and architectural fittings: House numbers, mailbox parts, garden tool components, signage substrates.

(Source : azurefilm)

2)  Automotive exterior components: Mirror housings, side trim, grille details — domains historically dominated by injection-moulded ASA.

3)  Garden and outdoor sporting goods: Garden furniture parts, sports equipment fittings.

4)  Functional prototypes for outdoor products: Prototypes that must survive multi-month outdoor testing without degrading.

(Source : Forgelabs)

5)  Marine fittings (non-immersed): Boat trim, console covers; UV + salt spray performance.

Photographs of representative parts in these applications are not reproduced here for copyright reasons; the table below provides direct manufacturer / case-study URLs where original imagery and project descriptions can be viewed.

TABLE VI
 SUGGESTED IMAGE / CASE-STUDY SOURCES

X.  REFERENCES

[1]  Stratasys, “ASA Material Data Sheet,” 2023. https://www.stratasys.com/en/materials/materials-catalog/fdm-materials/asa/

[2]  Polymaker, “PolyLite ASA Datasheet,” 2024.

[3]  Inslogic 3D, “ASA Filament Datasheet,” 2024. https://store.inslogic3d.com/products/asa-filament

[4]  ASTM G154-16, “Standard Practice for Operating Fluorescent UV Lamp Apparatus,” ASTM International, 2016.

[5]  ASTM G155-13, “Standard Practice for Operating Xenon Arc Light Apparatus,” ASTM International, 2013.

[6]  Filamentive, “Best 3D Printing Filament for Outdoors? UV Resistance Guide,” 2024. https://www.filamentive.com/best-3d-printing-filament-for-outdoors-uv-resistance-guide/

[7]  ASTM D638-14; ASTM D256-10; ASTM D648-18.