Why do I need support?
FDM 3D printing allows a lot of freedom and possibilities but is has some limits. One of these is due to overhangs, parts of the model that, relatively to the vertical axes, form an angle bigger than a certain threshold, usually 45 degrees. In these cases the layers of filament don’t have enough base to support themselves and may partially collapse, leading to unpleasant looking artifacts on the model’s surface or even to printing failures.
An extreme case of overhang are islands, when the new layer has nothing at all underneath so sustain it: in these cases support is mandatory in order to avoid printing failures.
Finally, bridges constitute a case in between: they might be able to print, 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, adjust the settings accordingly and decide whether you need support or not.
The general rule is: use less support as possible. Support is not nice, it slows the print, it might lead to failures, it leaves marks on the model after removal, however sometimes you cannot avoid it and being cheap on it might lead to even worse results.
As we have seen, overhangs are the reason why we need support. Voxelizer will automatically detect overhangs in the model and will raise a warning that suggests you to add support.
In reality, sometimes these areas are so small (or your printer is able to handle well overhangs) that you can safely ignore the warning. In some other cases though you can’t and the question becomes: 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 answer is not unique and it 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 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 might be able to use less support.
- Model stability: sometimes you don’t need support much for the overhangs but in order to give more stability to your model during the print.
- Model orientation: have you considered rotating your object so that it is in a position that requires less support? This is not always possible, because you might want to have the printing layers over a certain direction but it is something that you should consider.
- Support marks: you might want to play safe and put a lot of support but when your print is finished and you remove your support, you will end up with many marks on the model’s surface. This is something that you should consider, although these marks can usually be removed in post-processing.
What kind of support do I need to use?
There are different kind of support, each slicer developed its own type and algorithms to generate it. As per the amount, also for the kind of support there is not an unique answer about which one to use. It depends a lot on the type of model that you are going to print as well as, in some measure, to “personal taste”. You will have to experiment and build some experience before starting to feel confident on which kind 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 them and use suggestions.
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.
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.