In this article, we explore the main Cura support settings and show you how to optimize them to best support your overhangs.
All fused deposition modeling (FDM) 3D printers create objects by extruding layer upon layer of thermoplastic material. Consequently, each layer has to be held up by the layer beneath it. When there is no layer beneath it (as is the case with overhangs and bridges), the model might just need support structures. These are printed with the main model and come off during post-processing.
“That doesn’t sound too terrible,” you might think. Yet, the word “support” horrifies many makers; some even consider it to be almost profanity. After all, not only do support structures require more material, but they are also known for negatively impacting surface finish and being a pain to remove.
Unfortunately, some models just need supports. But that doesn’t mean we can’t optimize them through adjusting the appropriate settings…
In this article, we’ll first talk about when you do and don’t need supports. Then, we’ll dive into some important Cura support settings to adjust for the best results.
Note: This article is written specifically for Ultimaker Cura users, but the basic principles behind the settings can be applied to various other slicers.
There are a couple of things to consider in order to determine whether you need support structures or not:
If you’ve determined that you need supports, let’s dive into the settings to perfect them.
Cura has several settings to help you optimize your models’ supports. Here’s how to get started:
Now, you can see all the settings Ultimaker provides in Cura. Scroll down to the Support Settings, click “Generate Support”, and let’s begin!
After you click “Generate Support”, the first setting will be “Support Placement”. Here, you can select “Everywhere” or “Touching Buildplate”. As you can probably guess, this determines whether supports are printed everywhere (where needed) or only originating from the build plate.
In most cases, it’s best to select “Touching Buildplate” because building support everywhere can cause some nasty imperfections on your print’s surface.
Sometimes, however, you just need supports everywhere. This is the case with really complex models that would be impossible to print without supporting structures.
With this setting, you can specify the overhang angle beyond which you want to generate supports. As mentioned earlier, the default angle is typically 45 degrees. However, this may be different for your specific machine. Play around with an overhang test and find the perfect angle for your prints.
This angle might also differ per print. If you only want to support bridges in a specific model, you can select 89 degrees. If you want support for every overhang, select 0 degrees.
Ultimaker Cura supports various support structure patterns. Each exhibits a balance between strength and ease of removal, and some are better compatible with different shapes.
Fast and Easy
Note that, because of the single-direction nature of the above three patterns, they tend to be more vulnerable. Vibrations and skinny support structures, for example, can result in the nozzle not perfectly lining up with previous layers, which could cause problems in the long run.
Furthermore, if these patterns are caught even slightly by a traveling nozzle, they might detach from the surface below and collapse — sort of like an accordion!
Both grid and triangle are great patterns to achieve sturdy supports. They are resilient against vibration, however, they do increase print time and generally exhibit more contact with the support areas. This may lead to more difficult post processing.
Support density is very similar to infill density in that you are making a trade-off between strength, speed, and easy of removal.
High-density support structures are generally more rigid and can withstand vibrations. Also, the increased contact with overhangs makes high-density supports ideal for complex or detailed support areas. With high-density supports, expect more reliable support, but more filament usage, longer print times, and more difficult post-processing.
Low-density supports are ideal for normal support areas that don’t require many contact points. Low-density supports are more likely to respond to vibrations while printing, but they reduce filament cost, print time, and difficulty of support removal.
20% support density is a great place to start, but adjust this value according to the needs of your model.
This important setting defines the distance from the top and bottom of the support to the model. This setting has two sections: Top Distance and Bottom Distance.
A high value for these distances allows for a bigger gap between the model and support, meaning easier post-processing, and creates a smoother model surface, due to the reduced number of contact points. A low value is useful when you are trying to support complex overhangs that require high detail. However, a low value does make supports harder to remove.
As always, play around with some distances to find the perfect value for your printer.
X/Y distance is very similar to Z distance. It adjusts the horizontal distance between a model and its support.
Again, the further the distance, the easier the support removal process is. The shorter the distance, the stronger the support structure is.
Typically, a larger X/Y distance will mean better surface finishes on vertical sections. If vertical parts in your prints are roughed up by the adjacent supports, try increasing the X/Y distance.
A lower X/Y distance will lead to better support for overhangs, namely those next to vertical surfaces (around the “armpits”). However, they may cause surface imperfections to vertical surfaces and can make post-processing a pain.
Depending on the type of overhang you are attempting to print, the Z distance may contradict the X/Y distance. In Cura, however, you can select your priority with these distances, so that, in case of contradiction, the most important distance is maintained.
Typically, it is best to have Z override X/Y, because the Z distance is what really holds up the model.
However, you can always change this override setting if a certain model requires it.
You can also set a Minimum X/Y distance. Then, even when the Z distance takes priority, a minimum X/Y distant is still maintained.
Join distance adjusts the maximum horizontal distance between support structures. When two support structures are closer together than this value, they will be printed as one structure. The higher the value for this distance, the quicker supports will merge. If support structures are especially thin, this can help to provide stronger support for the model.
If you set this value too high, however, support structures may become dense and difficult to remove.
When support areas are very thin, it’s difficult for your printer to create sturdy structures to support such a small area. This setting allows you to set a horizontal expansion so that even small support areas are adequately supported.
Inputting a large value for this setting will always result in sturdier supports, but this setting does require your printer to use more filament.
For very small overhang areas, Cura allows you to print supports as towers that taper at the top to support areas smaller than your set minimum diameter. (Other support areas will use normal support structures.)
So that these support towers aren’t too weak, they have a larger diameter than the area that they support. You can always change this diameter in Cura. You can also adjust the angle at which your towers ascend to a point, so you can make your towers flatter or pointier.
If you’re still interested in optimizing your models, you may be interested in these other articles from All3DP:
Feature image source: Scott Cahoon / MatterHackers
License: The text of "How to Optimize Cura Support Settings" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.
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