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Support Is All You Need

3D Printing Supports Guide – All You Need to Know

Picture of Tian Ooi
by Tian Ooi
May 18, 2018

3D printing supports is often essential when printing a difficult model. But what's the right type of support? Which settings work best? This step-by-step supports guide will lead you to the answer.

Step 1: Decide whether your model needs supports

Models with different overhang angles
Models with different overhang angles Source: 3D Hubs

3D printing, like everything else on Earth, is limited by gravity. Despite its amazing ability to turn spools of plastic into toy soldiers, giant swords, and other fun models, 3D printers don’t print well over thin air…

To combat this problem, slicer software adds all sorts of 3D printed supports alongside your model. And once the whole thing is printed, those supports can be removed.

But not every 3D print requires supports — something to keep in mind when getting ready to print. A big part of 3D printing supports s knowing how to avoid them. First, ask yourself: Is 3D printing supports necessary for your model? 

Here’s how to know whether your model needs supports:

  • Angle of overhangs or bridges. Overhangs are places where the printer would have to print partially or completely over air, such as the arms of the letter T or Y printed vertically. Bridges are overhangs that are connected to the model on both ends, such as the middle of the letter H. These are typically measured by angle, measured from the Z axis above the overhang. For example, the letter T contains a 90 degree overhang, while the letter Y has a 45 degree overhang. If you spot severe overhangs in your model (above 60 degrees), you probably need supports. And if your model has overhangs of over 90 degrees (eg. a lowercase r), supports are necessary.
  • 3D printer model. Not all 3D printers are created equal. Try printing an overhang test to see how well your printer does. If a 60-degree overhang doesn’t look so good, you should put supports on models with similar overhangs.
  • Print speed. Generally, slower print speeds lead to higher quality prints. But when it comes to 3D printing supports, that’s not always the case. The faster the print speed, the better overhangs and especially bridges turn out. If you tend to print slowly, make sure to turn supports on.

As they say, prevention is better than cure. Here are some general guidelines to avoid having to print with supports:

  1. Orient the print correctly. As an example, let’s say we wanted to print the letter T. If we try to print it standing upright, we’re forced to 3D print supports as well. But if we simply rotate the model so that the T is lying flat, we don’t need supports at all, saving both material and time. Make sure your model is in the best orientation to minimize 3D printed supports.
  2. Reduce overhang angles. If you created the model yourself, consider editing it so that overhang angles are reduced. Fillets and chamfers can smoothen out sharp angles, greatly increasing the quality of the 3D printed overhang. 
  3. Consider splitting the model into two parts. Spheres are one of the trickiest shapes to 3D print, as the huge overhangs near the bottom tend to come out pretty ugly, even with supports. In such a case, it’s much easier to print two halves of the sphere separately and glue them together for a beautiful, support-less finish.

Step 2: Pick a support type

A selection of lattice support patterns
A selection of lattice support patterns Source: Ultimaker

So yes, you’re sure that you need supports. In Cura (or your preferred slicer) you can simply check that box and call it a day. But there are so many more ways to 3D print supports that may work well for your case. 

Lattice supports are the most common type of support. They’re popular because they’re easy to customize, quick to generate, and work well for most 3D models. The downside is, if not printed properly, the supports can leave marks on the finished model and can be a pain to remove.

  • Use for flat, angular, or very steep overhangs.
  • In Cura: If you can’t see the ‘support pattern’ option under supports, simply click on the settings gear and make sure it’s checked. Then, use the dropdown to select your preferred support. Switch from solid view to layer view in the top middle to see what it looks like.

The default support type in Cura is a grid-pattern lattice support, which is reasonable since grid patterns serve as a great all-purpose support shape. However, there are actually 7 support patterns to choose from under the hood (some of which are pictured above). Make sure to pick a support pattern that fits your model’s shape. Concentric, for example, is useful for spheres and other shapes that aren’t evenly supported by a grid. Lines are great for when you need super-easy-to-remove supports, such as tricky holes or floors of a building. The other patterns are a little less commonly used, but feel free to experiment with them if the need arises.

Tree-type supports are almost exactly what they sound like. They start from a couple of ‘trunks’ near the base of your print, and branch out to support overhangs in your model as height increases. 3D printing these supports can save on material and print time.

  • Use for organic shapes (humans, animals).
  • In Cura: Click on any settings gear and check to show Experimental > Tree Support. Then, close the window and scroll down the print setup page and tick the Tree Support box to generate supports. Make sure your model is properly positioned and oriented first, since they can take a long time to generate!

Since tree-type supports don’t touch the model so much, they often offer better surface finish. However, they can take a long time to slice, since the trees are generated dynamically. Pick these supports if your model has lots of organic shapes, or overhangs that are small or not very steep (less than 70 degrees). These supports do not work well for flatter overhangs, such as a roof, since they only touch the model at a few points.

Dissolvable supports are a niche but high-quality alternative to typical supports, which are printed in the same material as the model. With the introduction of dual-extruder printers, one nozzle can print the model in PLA while the other prints all the support material in a water-soluble filament (commonly PVA). When the 3D print finishes, simply soak the print in some water and the supports will dissolve, leaving a clean model behind. How easy is that?

If you’re lucky enough to own a dual extruder printer and don’t mind paying for some slightly-pricey filament, we definitely recommend this option. Read this in-depth guide to learn more.

Step 3: Set the support density

What 10% density looks like in Cura
What 10% density looks like in Cura Source: Tian Ooi

The next step is to decide the best density at which to 3D print supports. We recommend starting at a density of about 10% and then adjusting to your liking. To see your sliced supports in Cura, hit ‘Layer view’ and ‘Show helpers’. Here are some factors that affect support density:

  • Print speed. The faster you print, the less dense your supports need to be to get a good quality finish. 
  • Desired print quality. For higher quality overhangs, you can increase density (at the cost of wasted material and print time). If it’s too high though, support removal can sometimes damage the print.
  • Size of overhang. The bigger the overhang, the denser supports you need. Especially for 90 degree overhangs, a support density of at least 15% is recommended.
  • Support removal. The denser the supports are, the harder it is to remove them. Also, the denser supports are, the more material you waste.

Above and Beyond: Advanced Support Settings

Regular supports, PVA supports, and a mix of both. It's possible!
Regular supports, PVA supports, and a mix of both. It's possible! Source: Prusa Printers

Cura, an open-source software, has lots of other settings to fiddle with so you can perfect your print. You might never need to touch these settings, but it’s always good to know they’re there.

  • Support placement. You can pick where Cura will generate supports: everywhere (including on the model) or build plate only (only touching the bed). 
  • Support overhang angle. This controls the minimum overhang angle where Cura will generate supports (default 60 degrees). If your printer can handle up to 70 degrees pretty well, changing this setting occasionally helps to save filament and support removal work.
  • Support Z distance. This is the gap between the top layer of the support and the first layer of the model. A little space is needed so that the supports can be broken off easily and don’t actually melt into the model. If you find that your supports are a little too glued to the model, consider increasing this value a little bit.
  • Gradual support infill steps. Cura has a neat little option to help you save on print time and material. For those really tall and dense supports, Cura will 3D print supports at a lower density on the bottom and higher density up near the model, where you actually need it. This setting controls the number of times to cut support density in half from the top down. 

Let's Go!

An example of tree supports
An example of tree supports Source: wrong account, Pinshape

You’re ready to print! Pat yourself on the back for setting up your print for success. Don’t be discouraged if things don’t turn out as you planned — 3D printing supports is full of trial and error, and the best way to learn is through experience. 

Related articles:

  1. 3D Printing Support Structures All You Need To Know
  2. Cura Tutorial – Deep Inside the Cura 3D Slicer Software
  3. 17 Best 3D Slicer Software Tools for 3D Printers (Most are Free)

License: The text of "3D Printing Supports Guide – All You Need to Know" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.

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