If you print parts that live outdoors, ABS filament is probably the wrong call. Most engineers and hobbyists default to ABS because it’s familiar. It runs well on most machines and has been around long enough to feel like the safe pick for functional printing.
But ABS has a known weakness: UV exposure breaks it down. ASA filament was engineered to fix this problem. It matches ABS on most mechanical properties, prints easier in real-world setups, and holds up in sunlight, unlike ABS. Here’s the chemistry behind the difference, the spec comparison, and when each material is the right pick.
What Makes ASA Different from ABS
The difference between ASA filament and ABS filament comes down to a single component swap in the polymer chain. While the swap might seem small on paper, it is significant in the field, especially anywhere the part has to face direct sunlight.
The Chemistry Behind UV Resistance
ABS stands for acrylonitrile-butadiene-styrene. The butadiene component is what gives ABS its impact resistance. It’s also what makes ABS fail in sunlight. UV energy breaks down butadiene-based polymer chains, resulting in parts yellowing, losing impact resistance, and cracking.
ASA replaces butadiene with acrylate rubber, which is the core chemistry difference. Acrylate is far more UV-stable, so ASA parts maintain their color, stiffness, and mechanical integrity through extended outdoor exposure. An ABS part can show visible yellowing after a few months outside. The same part in ASA looks and performs the same six months in.
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We manufacture all of our printers and filaments in our 68,000 ft² manufacturing facility (located in Grand Rapids, Michigan) using state-of-the-art equipment and processes. Our goal continues to be to make the most innovative filaments on the market – targeting difficult end-use applications where functionality is king.
