Since I began 3D Printing, I’ve found supports to be a frustrating necessity. They do perform a job, but they are a real pain in the behind. Sometimes they stick too well and can’t be removed, they make prints take longer, they mar the surfaces. All around, they are just a bummer. However, if you start to dig into how they work, and how to adjust them, you can really get some great results.
The team at Prusa 3D shared some tips with me on four areas to tweak for improvement on my 3D printing supports.
Just turn them on, but turn them on right.
When you enable supports, you’re given two options: Everywhere, and From build plate only. This first choice presents a bit of confusion for many people. Everywhere, is exactly as it sounds. The slicer will place supports anywhere it deems necessary.
The second option, “from build plate only”, tells the slicer that you only want supports to be built on the plate of the printer, never from on top of a printed part or on an internal cavity. Often this option alone will save you much heartache.
The final option, “support enforcers only” will be useful on the last step in this article. it means it will only put them in places you’ve specified.
Adjust support angle
The slicer analyzes your print and finds “overhangs”. What determines if an overhang gets a printed support is the angle at which it is dangling out into mid air. By default, the slicer is set to a very conservative number, like 55 degrees. This, according to the Prusa team, is simply to ensure that even beginners will have successful prints.
For those who are up to a little tweaking, and know their printer is capable, you can adjust that angle to a lower number. This means that it takes a more extreme overhang to trigger a support structure. On my Prusa I3 Mk3s, I can pretty confidently go down to 8 degrees.
Adjust the amount of separation
This one is something I haven’t really had problems with in a long time, but when it does appear it is quite frustrating. Sometimes your supports stick to the 3d print that is placed atop them. I primarily print in PLA, and the defaults work well, but sometimes switching materials (or using different printers) can mean you need to adjust this.
Decrease the gap too far, your prints will stick to your supports. Increase it too far, and the bottom surface of the print will be saggy and droopy and overall just ugly.
Manually place your supports
One of the most powerful tools in your toolbelt. Once you have a good feel for how your supports work, and how your printer handles them, you can get specific in placing them exactly where you want.
In prusa slicer, right click on an object and look for support enforcers (and blockers). You can add these basic geometric shapes in areas that you want supports to appear(or not). This is ideal if you have a print that you know should only have supports in one spot, or more often, a spot you know should not have supports.
In the latest versions of Prusa Slicer, you can now also manually paint on these supports instead of placing the enforcers and blockers. Once you have given this a try, it is hard to consider going back to the older methods. Not only is painting supports manually a much more refined approach, there are tools allowing you to hide parts of your model, improving your view into tricky areas for support placement.