Support structures are a necessary evil that most people into 3D printing will be familiar with. If you’ve got overhangs or bridges that are too long, then you need to print more material to support them during the printing process that you can just cut away and discard afterward, once the print is finished. Unfortunately, the removal of support structures almost always leaves behind artifacts on the surface of the print, while you can try sanding the print down, this can just make things worse.
Troubleshooting Tips For Rough Surfaces
Most people configure their slicing or 3D modelling software to automatically generate support structures for them. This dramatically reduces the amount of time you’d have to spend if you were to add support structures manually but there are still some settings that you can configure. For example, most software offers the ability to choose between support structures everywhere or only where they touch the build plate. Choosing to use support structures that only start at the build plate significantly reduces the number of surfaces that have contact with the support structures, and so reduces the amount of post-processing that is necessary, especially on the more visible upward-facing surfaces.
It is a good idea to print a test print that tests your printer’s ability to print difficult geometry such as bridges and overhangs without support. By dialing in your settings with a test print, you may be able to reduce the number of support structures you need or be able to avoid printing them at all as your printer may be better at handling bridges and overhangs than you think.
The type of support structure you use affects both the amount of support it offers and how much contact is made with the print. If your print doesn’t need much support, you may not need to use a strong or particularly dense support structure, instead, you can choose to use lighter patterns such as lines or zigzags. You can also choose to reduce the density of your support structures, this reduces the amount of material they use, making them faster to print, cheaper, and easier to remove, at the cost of potentially not providing enough support if you lower the density too far. On a well-tuned printer, you can reduce the support density to around 5% before encountering issues.
Checking the printing temperature range for the filament you’re using is also a good idea. If you can lower the print temperature by a few degrees you will end up with a weaker bond between layers, but also a weaker bond with support structures, making them easier to remove. Just make sure to double-check that none of your layers are cracking apart as this indicates that the print head temperature is just too low.
A more expensive but robust solution would be to use a dual extrusion 3D printer combined with a soluble support material. An independent dual extrusion (IDEX) 3D printer can print with two different filaments at once. If you use this functionality to print with a filament that can be dissolved, then you can print support structures that can simply dissolve away leaving no artifacts on the surface of the print. PVA is the most common dissolvable filament as it dissolves in water, HIPS can also work but this needs to dissolve in limonene.
Hopefully, these tips help you to improve the quality of your prints by reducing the artifacts left by support structures. If you’ve any other tips for addressing rough surfaces after removing support structures, feel free to share them down below.