Material Monday: ASA Filament

In the past, I wrote a weekly article for the Make: Blog that we called Filament Fridays. It was a collection of 3D printer filaments each having a unique characteristic. I’m excited to bring these back as Material Mondays, but instead of just focusing in on 3D printer filaments, we are going to discuss lots of materials that Makers can use to create their projects. Most of these will still be digital fabrication focused, but on top of FFF filaments we will also include SLA resins, laser cuttable materials, CNC materials and a host of other goodies. If there is a material you would like to see me put to the test and write about, drop me an email or hit me up on twitter, @MattStultz.

This week we are sticking with the filament roots and taking a look at ASA filament. ASA or Acrylonitrile Styrene Acrylate shares many of the same qualities as ABS but comes with a few bonuses also. Like ABS, ASA has a high glass transition temperature and impact resistance compared to PLA, making it more resilient for use in projects that might be in a warm place or might receive heavy wear. The big advantage ASA has over many other materials is its UV stability. UV rays from the sun break down and damage many plastics. If you’ve ever had an old computer or lawn furniture that starts to turn yellow after sitting in the sun for a long time, that is UV damage. Beyond just making your objects look old and dirty, UV damage can make plastics brittle. ASA’s chemical bonds resist UV damage making it a great choice for outdoor applications that you want to stand the test of time.

Of course, no material is perfect, and ASA shares some of ABS’s downsides also. Shrink is an issue, and ASA requires a heated bed or chamber for proper printing. I found large flat objects to be tough due to warping with ASA even on a heated bed, so think about building an insulated chamber if you are planning on printing a lot of the stuff. While the fumes were not as bad as those from ABS, they are still there and you should consider ventilation when printing with ASA.

For my test print, I used Fillamentum ASA Extrafill Green Grass. The print came out a little rough and definitely could have handled overhangs a bit better (bringing the temp down from the default I think would help this a lot). There were no stringing issues though and the fine details came out clean.

ASA is not likely to replace PLA as your daily print material but for anything you plan on leaving outside, it is going to be your best option.