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Engineering Plastic

ASA

ASA is essentially a UV-stable cousin of ABS: similar mechanical properties, about 45 MPa tensile, plus excellent weather and color-fade resistance. Its acrylic-rubber phase resists the sunlight-driven yellowing and embrittlement that degrade ABS outdoors, making ASA the default for parts that must look good after years outside.

How ASA machines

Rated 3.5/5, comparable to ABS. It machines cleanly with sharp tools and good chip clearance, and its toughness resists edge chipping better than brittle styrenics. Manage cutting heat to avoid melting. Most ASA parts are molded or 3D printed, with machining mainly for prototypes.

Manufacturing & processing

Injection molded, extruded, and increasingly 3D printed, where it is valued as a weatherable alternative to ABS for outdoor prints. It paints and bonds like ABS. The defining trait is durability under sunlight and weather, retaining color, gloss, and impact strength far longer outdoors.

Typical applications

Outdoor and automotive exterior parts: mirror housings, grilles, trim, antenna covers, signage, garden and recreational equipment, and exterior electrical enclosures. Anywhere ABS would yellow and crack in the sun, ASA is specified to hold appearance and properties.

When to choose it

Choose ASA whenever a tough, ABS-like part lives outdoors and must resist UV fade and embrittlement. If the part stays indoors, plain ABS does the same job for less. If you also need higher heat or impact, consider PC/ABS or PC, accepting their higher cost.

Suitable surface finishes

Common finishes for ASA: bead blasting, powder coating. Use the finish selector →

FAQ

What makes ASA weather-resistant where ABS fails?
ABS uses a butadiene rubber phase that UV light attacks, causing yellowing, chalking, and embrittlement outdoors. ASA replaces it with an acrylic-ester rubber that resists UV degradation. The result is similar strength and toughness to ABS but with far better retention of color, gloss, and impact strength under sunlight.
Is ASA a good choice for outdoor 3D printing?
Yes. ASA has become a popular weatherable alternative to ABS for functional outdoor prints, holding color and toughness in sunlight. It prints similarly to ABS, needing an enclosure and good ventilation to control warping and fumes, but rewards the effort with durable exterior parts.
Should I pay extra for ASA over ABS?
Only when UV exposure matters. For indoor parts, ABS gives the same mechanical performance for less. For anything in direct sun, signage, automotive exterior trim, outdoor enclosures, the modest premium for ASA prevents fading and cracking that would otherwise ruin an ABS part within a season or two.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.