ABS Print & Bed Temperature – All You Need to Know

Acrylonitrile butadiene styrene, abbreviated as ABS, is a common plastic that is found all around us, famously used for making Lego bricks. Its properties, such as high strength and good temperature resistance, makes it a good choice for many applications. 

ABS also offers the possibility of a good surface finish. ABS reacts to acetone, which tends to smooth and polish the surface. It’s also a lot easier to sand ABS.

ABS can be a little tricky to print with. One issue you may face while printing ABS is that it’s hard to get it to stick to the bed. The printed part tends to “warp” from the sides and the fumes generated can be unpleasant. But we’ll get to all of that soon enough!

Before we jump into the “how-to” of this article, we need to understand what the term “warping” means.

When filaments are heated in the extruder, they have a tendency to expand. Once in their molten state, the plastic is deposited onto the build platform layer by layer. As the molten plastic cools to solidify, it also contracts. Some plastics tend to expand and contract a lot more than others.

While printing a part, the first few layers start cooling off after being printed. As the plastic cools off, it begins to contract, which causes it to peel off the build platform. Warping is common among ABS and nylon filaments, as they have a greater tendency to expand and contract than your regular PLA.

Printing with ABS can be a bit hard, but with the right settings, it’s a cake walk. Let’s take a look at the changes that are required to tune your heaters for ABS.

Extruder

ABS melts somewhere between 210 and 250 °C. Unless specified by the manufacturer, you should be able to play around with temperature settings in this range. We find, for example, that 235 °C does a pretty good job.

If you’re running the extruder too hot, you’ll notice a lot of strings created between the walls of your part. If you run it too cold, you might find it under-extruding. Here are some good test prints to try different temperature settings.

Heated Bed

The most important purpose of a heated bed is to eliminate warping, so setting the correct heated bed temperature is crucial. The temperature at which a plastic changes phase from a solid to molten liquid is known as the glass transition temperature (Tg). You’ll want to set the heated bed temperature just above that point.

For ABS, the glass transition temperature is 105 °C, hence a bed temperature of 110 °C should suffice.

The slicer has multiple settings that can be tweaked to your advantage.

• Brim and raft: The brim and raft options in the slicer settings give additional surface contact between the part and the build plate. This helps with first layer adhesion and, at the same time, the brim or raft also acts as a sacrificial addition. In case of warping, the brim or raft will be affected while the required part remains in good condition.
• First layer height: Having a thicker first layer can be beneficial, as it increases surface contact, which in turn holds the print firmly in place. A standard rule of thumb is to set the first layer at 150% of the regular layer height.
• First layer speed: The print speed for the first layer should be decreased to about 70% of the actual print speed. This is especially useful when your part has sharp corners, which tend to peel off when the hot end moves at higher speeds.
• Draft shield: The draft shield is a great feature in Cura that’s hidden away in the experimental settings. It’s a single-layer-thick wall built around the part that stops a “draft of air” from hitting your part. It’s been said to improve ABS printing and keep warping at bay.
• Cooling fans: Cooling fans are a great addition to 3D printers, as they create a good amount of airflow around the nozzle and cool the plastic quickly. This can have a negative effect when printing the first few layers, though. Make sure to turn off the fans for the first 5 to 10 layers before turning it on.

Machine Enclosures

An enclosure for your machine ensures that the heat stays within the machine and keeps the part from warping. From experience, we’ve had parts warp even with a heated bed due to an open machine frame in a well-ventilated room. Take a look at our article on DIY enclosures, which covers this topic in great detail.

Adhesives for the Bed

Another option that seems to be effective in fighting warping is the use of adhesives. Glue sticks can be directly rubbed onto the build platform, helping the print adhere to the platform better. Melting a small amount of ABS and spreading it onto the build surface can also be effective. Hair spray is another good option.

Design Changes

It does help to know that sharp corners in the design can aggravate warping, as stress from warping gets concentrated onto a single point. Rounded corners help distributing the stress over a curved path and hence reduce the stress concentration at any single point.

With a little bit of practice and the right settings, you’ll soon master the art of printing with ABS! And it’s a handy material to master, given its usefulness in functional parts and harsh environments. This is definitely a great skill to have in your tool box.