Supports in 3D Printing and How to Reduce Them (FDM)

May 5, 2024

What are supports?

3D printing is an additive manufacturing process where material is layered over and over to produce a product. This process has been growing in popularity recently and it gives endless possibilities to what can be created. Fused deposition modelling (FDM) is a method which melts materials and and extrudes them in layers and in a pattern. It is the simplest method of 3D printing and is one of the most popular.

The layers in an FDM print need something to rest on. Supports are often automatically put in when there is an overhang or bridge. This can be illustrated using the letters Y, H and T. Y and T have overhangs, while H has a bridge.

‘YHT’ printed without supports (Source: MVP Consultancy)ALT

As seen from the picture, H and T have a messy print as there is nothing to support the material being printed. This means the material is being extruded into the air. However, Y comes out perfectly. This is because of the angle of the overhang. The bigger the angle, the less each layer is being supported and thus would fall.

Layers in 3D printing

There are 2 different types of supports in FDM printing: linear and tree.

Linear Supports

Linear supports come in a few patterns. The most common one is a zig-zag pattern. When printed, they look like long columns under the overhang. They are good for bridges and any sort of steep or flat overhangs due to their strength. However, linear supports are hard to remove. Usually, a needle-nose plier is needed to reach into small spaces to remove the supports. Linear supports may also easily damage the model during post processing. They often also take a lot of time and material to print, thus making it wasteful.

Support patterns (Source: Ultimaker)

One way to combat damaging the surface is to use soluble supports. Some 3D printers are able to use 2 filaments at once. By using a water-soluble material as your support, you can simply soak the print in water when it is done. This makes removing the supports much easier too.

Water soluble supports (Source: Gambody)

Tree Support

Tree supports look just like their name suggests. They look like branches that start off thick at the bottom and thins as it goes upwards. These supports have the options of being hollow or with infill, and Cura (a free slicing software) allows you to customize how you want your supports to be. With less material used, printing time is also shorter. The surface finish is also much neater when compared to a linear support. However, using tree support increasing the amount of time it takes to slice your model. Calculating the tree supports would also take more time and require some thinking.

Tree support (Source: Gambody)

People are starting to use tree supports over linear supports thanks to its many benefits. While the set up and slicing might take longer, it is worth it for a finished product that looks good and takes less time to print and process.

Reducing supports

A good rule to follow is to keep your prints at least 45 degrees. This allows the material to support itself and will give a print without needing any supports. In the photo below, it is a test for 3D printing angles. It ranges from 5 degrees to 70 degrees, and as the angle increases, the print becomes messier. Thus, a good way to decrease the amount of support needed is to decrease the angles in your design.

Angle test (Source: 3D Hubs)

Of course, this is not always possible. Another way to decrease the amount of support needed would be to orient your print differently. For example, if you are printing T, instead of printing it bottom to top, you can print it front to back. This means that the finished product would be lying flat and will have no overhang and would not need any supports. Sometimes, if your design allows for it, changing the orientation of a part of your model will also lead to less supports and an easier clean up.

‘T’ lying down (left) vs ‘T’ upright (right)

In FDM prints, it is possible to design in a manner that completely requires no support. However, for many models, this might not be feasible. Following the guideline about angles and orientation would allow you to save on material and time.

Conclusion

Comparison table for tree support vs linear support

3D printing is a great way for quick prototypes and allows you to create anything as you can think of. In FDM printing, we often want to be efficient with out time and materials and taking supports into account can help us save these resources.

Thank you for reading!