Supports 101

Why do you need supports?

FDM 3D printing allows a lot of freedom and possibilities but is has some limits. One of these limits is because of overhangs. Overhangs in 3d printing are parts of the model that, relative to the vertical axes, form an angle larger than a specific threshold, usually 45 degrees. In these cases the layers of filament don’t have enough of a base to support themselves and may partially collapse, leading to either unpleasant looking artifacts on the model’s surface or to printing failures.

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An extreme case of overhang are islands. An island is when the new layer has nothing at all underneath to support it: in these cases support is mandatory to avoid printing failures.

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Bridges are somewhat different than overhangs or islands: they might be able to print without support, depending on your printer, filament, printing parameters (such as speed) and, most of all, length of the bridge. There are different tests available that you can use to evaluate the capacity of your printer and filament to print a bridge. These tests will help you decide if you need supports and to adjust the settings accordingly.

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The general rule is: use the least support possible. Keep in mind that support slows the print, may lead to failures, and will leave marks on the model after removal. However there are times when you cannot avoid them and trying to save time or filament by printing without supports may lead to a failed print.

Since overhangs are the reason we need supports Voxelizer automatically detects overhangs and islands in the model and will display a warning that suggests you add support.

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In reality, sometimes these areas are so small (or your printer is able to handle overhangs well) that you can safely ignore the warning. In other cases they can’t be ignored and the questions become: how much support do I need? Which threshold angle should I use for our my model? 45 degrees is a safe bet, but can we push it a little further? The answers depends on few parameters:

  • Printer: different printers can handle overhangs differently, depending on their precision. With ZMorph, for example, it is usually safe to print without support until the angle reaches 60-65 degrees.
  • Filament: different filaments behave differently on overhangs, you will have to experiment with the ones you use.
  • Printing speed: printing speed is important: if you print slower you may be able to use less support.
  • Model stability: sometimes support isn’t needed as much for the overhangs as to give stability to your model during the print.
  • Model orientation: consider rotating your object so that it is in a position that requires less support. This is not always possible, because you may want to have the printing layers in a particular direction but it is something you should consider.
  • Support marks: you might want to play it safe and use a lot of support only when your print is finished and you remove your support you end up with many marks on the model’s surface. This is a consideration when you decide how much support should be used. In most cases, however, the marks can be removed in post-processing.

 

What kind of support do you need to use?

There are different kinds of support, each slicer has its own support types and algorithms to generate them. Each model will need to be evaluated to determine the type and amount of support that is needed. There is no single answer. What you decide depends on the type of model that you are going to print and, to some extent, “personal taste”. You will need to experiment and build experience before you start feeling confident about which type and amount of support to use.

In Voxelizer there are 4 kinds of support: Simple, Outline, Tree and Lattice. Please refer to our specific article for a detailed description of each of them and suggestions for their use.

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How can I apply the support to my model? 

Applying support in Voxelizer is very easy: just choose one of the support presets from the dropdown list, then specify the Cutoff angle.

If you have multiple objects, you can specify a different kind of support for each one of them: right-click on the object and specify the support preset that you desire under the Settings tab.

To create and modify a support preset go to the specific panel. See the article about the types of support for the parameters that you can modify.

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As you have understood by now, when it comes to support, there is not an unique answer. Each time you will have to look at your model, find the critical areas and decide what is the best support type for this specific situation and how much of it to use. Always look at the gcode preview first, check that it “looks good”, in case compare few versions. Finally, print. If your model is complex it might not work at the first shot and you will have to understand what went wrong and which parameters to change. Please refer also to our Advanced support guide for some more specific tips.

 

Tips and tricks

  • Each support has a Filament amount parameter. Try to reduce it below 50% to facilitate support removal.
  • When it comes to simple support (Light and Dense) the support_infill_angle parameter might make a difference between a failed and a successful print. Try to change the orientation of your support, so that it is perpendicular to the extrusion lines of your model.
  • If your Light and Dense support don’t stick well to the table, just add the power-raft and solve the problem (or ri-calibrate your printer).
  • If you reduced the Filament amount parameter in Solid support, you can also reduce the Support offset parameter (to 0.2 / 0.3 mm); in this way it will better sustain the model and it will be easy to remove.
  • If you use Solid support, you can assign to it a custom Durability preset by right-clicking on it. For example you could print your model with a Strong durability preset and your solid support with a Light one with small infill. In this way it will be much easier to remove.
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