ASA is a common alternative to ABS and is great for outdoor applications due to its high UV, temperature, and impact resistance.

Overview

ASA, also known as Acrylic Styrene Acrylonitrile, is a 3D printable plastic with properties similar to ABS. It was originally developed as an alternative to ABS that would be more UV resistant by changing the type of rubber that’s used in the formulation. ASA is known for high impact resistance, higher temperature resistance, and increased printing difficulty. It’s commonly used in outdoor applications instead of ABS due to its superior resistance to UV and harsh weather conditions. Due to its heritage, ASA still retains many of the same printability drawbacks that are seen with ABS. Warping is still a consistent issue that you need to account for, as well as the potentially dangerous fumes that the plastic emits during printing, due to the presence of Styrene.

Hardware Requirements

Before 3D printing with ASA make sure your 3D printer meets the hardware requirements listed below to ensure the best print quality.

Print Settings

Bed temperature: For ASA, it’s recommended to have the build plate temperature set between 90 and 110 °C, depending on the filament brand. Filament manufacturers usually recommend specific bed temperatures.
Nozzle temperature: This material prints at a relatively high temperature, usually falling within the 240 to 260 °C range. For ASA, printing too hot is better than too cold, as higher temperatures provide better layer adhesion.
Cooling: No cooling is required for printing with ASA. In fact, it’s generally recommended to leave it off. However, very low speeds (5 to 10%) might improve overhangs and overall print quality. We suggest first focusing on having good layer adhesion, and once that’s been achieved, try using the cooling fan to avoid overheating issues.

Best Practices

These tips will help you reduce the chances of common 3D printing issues associated with ASA such as warping, shrinking, and poor bed adhesion.

Invest in a Good Build Surface

For ASA to stay anchored to your build surface, we recommend using a layer of Kapton tape on top of your printer’s heated bed. Applying this layer of transparent tape will add about 0.1mm of thickness on top of your bed, so be sure to account for this in Simplify3D by increasing the global Z-axis offset on the G-Code tab of your process settings. If your printer uses a glass bed, you can also use PET sheets, which provide similar adhesion but maintain a smooth surface finish for the underside of the part. These solutions will all help to mitigate the warping that is commonly experienced with ASA prints.

Adjust Temperature and Cooling Setting to Prevent Overheating

Due to the higher temperature that is required for printing in ASA, these parts are frequently prone to overheating, which can create significant print quality issues. Simplify3D allows you to define custom temperature values at different locations in your print, so a great way to deal with this problem is to print the bottom few layers of ASA with a higher extruder temperature, and then decrease the temperature by 5 degrees a few layers later. You can repeat this process 1 or 2 more times so that the top of the part can be printed without overheating issues, while the bottom was printed at a higher temperature to help with adhesion.

Use Slow Speeds for the Cooling Fan

When printing with ASA, it can be difficult to overcome the effects of overheating. As mentioned above, lowering the temperature for higher layers in the print is one option for combating this issue. Another option is to enable the part cooling fan on your 3D printer to run at a very low speed. Values in the range of 10-25% typically work best, adding some additional cooling without inducing excessive warpage or shrinking.

Pro-Tips

A slurry of ABS or ASA and acetone on top of a heated build plate will give an excellent film onto which your parts can adhere.
ASA can be smoothed using controlled exposure to acetone vapors (a process called “vapor smoothing”).
HIPS can be used as a great dissolvable support material for ASA prints. Consider using the Dense Supports option in Simplify3D for best results.

MORE TIPS:

if you’ve never printed with ABS or ASA before, there’s a couple tips and tricks you want to know before you get started, and with this guide, you’ll be printing with ASA 3d printing filament in no time.

How To Succeed When 3D Printing With ASA Filament

Step 1: Make sure your first layer is right

Making your first layer right is a two-part process: you need to make sure your bed is level, and you need to make sure the nozzle is the right distance from the bed.

Leveling the Bed

To level the bed, you need to follow the instructions provided with your printer. Every printer has it’s own method, with some having guided wizards, auto bed leveling, or you’re completely on your own. In most cases, 3D printer bed surfaces are leveled using three or four screws attaching the bed to a carriage. Tightening or loosening these screws changes the plane the bed is on, if your bed itself isn’t bent. In general, though, the procedure to level a bed is:

Move your print head out of the way of the bed to prevent it from crashing if it’s too close.
Home the Z axis. This will move the nozzle to as close to the bed it can get. If there’s room between the nozzle and the bed, perfect. If there isn’t room, tighten the screws under the bed until there’s about 1mm of space.
Move the print head above one of the three or four screws and insert a piece of paper between the bed and the nozzle.
Gently loosen the screw until there is a very slight amount of resistance between the bed and the nozzle. Just enough to notice, but not enough to require force to move the paper out.
Repeat this with the rest of the screws. The key is to get the same resistance at all points; this means your bed is level.

Adjusting Nozzle Distance

Now that the bed is level, you need to make sure the nozzle is at the right distance from the bed.

Make sure your bed material of choice is applied at this point.
Start a print with a skirt that covers the entire area of the bed.
Watch how the filament is laid down. Is it really smearing out the sides of each pass and looks like it’s bubbling up against each other? You’re much too low, and should bump it up a little bit at a time. Is there a clear distinction between each pass of the skirt? You’re too far away and need to lower the nozzle.

Step 2: Print bed and adhesion.

If you don’t have a heated bed, ASA isn’t going to work for you. Just like its predecessor ABS, ASA is really temperature sensitive and warps and splits if your temperatures aren’t quite right.

If you do have a heated bed, here’s what you can do:

Print with a brim. I use a brim of about 15 loops. I very rarely need more loops than that, but with the right temperatures, an enclosure, and adhesive, sometimes I can get away with not using a brim at all.
A light spray of Aqua Net Hairspray on the bed and printing with a bed temperature of 110C works really well. 110C works if your printer can make it there, but for some 3D printers, they just can’t make it. In that case, print at whatever it’s max temperature is and hope for the best. I’ve been successful as low as 90C before, but that was a very well calibrated machine. In addition, make sure you’re using specifically Aqua Net, though; other brands may work but Aqua Net is tried and true.
If you want something more controlled than hairspray, you can also make ABS juice
You can also use Kapton tape on top of your heated bed in addition to hairspray. It helps uniformly spread the heat on your bed so you don’t have warpy corners, and it produces some really nice, glossy bottomed prints.

Step 3: Calibrating your print temperature.

For ASA, I generally print at 250 degrees Celsius and a bed temperature of 110 degrees Celsius.
You may need to fine tune your printer to get results you are happy with, and you can do that by adjusting temperatures up or down 5 degrees at a time.
Printing too hot for ASA isn’t as big of a problem as printing too cold:
1. A cold ASA print will warp or split, or have terrible layer adhesion,
2. A hot print will have better layer adhesion, with some stringing and some rougher overhangs.

Step 4: Tips to Solve Warping and Splitting

Even if you’ve done all that right, you might still have some issues with your prints and that’s the same difficulty that ABS faces: it warps. A slight draft and you have a ruined print from either the corners warping up or a split forming on that layer - where the previous layer cooled quicker than the next layer could adhere to it. Here’s two key things to take care of it:

Build an enclosure for your printer, either as basic as a trash bag, some plastic sheeting and PVC

Turn off layer cooling fans. These can cool your prints too quickly, which works well for PLA or even PETG, but for ASA, it’ll cause splits and issues in your print. You may be able to turn them up to a gentle 10% with some success, but do a couple small test prints before committing to a 24 hour ASA print with the fans on.