When designing and printing 3D parts, it’s important to keep in mind how the part will be built. Most printers have the option to add some sort of support to overhanging structures to prevent drooping and sagging and maintain part integrity.
Through careful design choices, you can create parts in a way that reduces or even eliminate those overhangs, ultimately reducing the need for support. This can reduce print time (the time it takes to switch between support material and model material can add up!), post-processing time, and material use.
One of these design choices is to use self-supporting angles. Overhangs require some sort of support to prevent the plastic from falling right off the model. But with self-supporting angles, the plastic will overhang the previous layer slightly and – because of the properties of the plastic – will not droop or sag.
For example, I am designing a nightlight. This cross-section view highlights in red some of the overhangs in my design.
Here’s a view of the supports generated in MakerBot Print. Green is the model material and orange is the support material. You can see how much support the middle of the part will need with this design. The total estimated print time is 15 hours and 51 minutes using almost 204g of material.
Now, I redesigned the body to use self-supporting angles, which is highlighted in green below. A good rule of thumb for self-supporting angles is to stick to about 45 degrees from horizontal, although that will vary based on the material used and the actual design itself. In this case, I used 30 degrees.
The red highlights show where there are still overhangs. However, I shortened the overhang to be equal with the ledge below to reduce the need for as much support.
Here is a view of the re-designed body in Makerbot Print. The total estimated print time was reduced by almost 5 hours to 11 hours and 3 minutes and the t otal material usage was cut by 50g. I tested this model using different slicing software and different printer templates and the time savings alone could be up to 8 or 9 hours, which cuts print time in half!
Not every design will be able to be modified in this way, but experiment with some designs and different angles to understand which types of self-supporting angles you might be able to incorporate into your parts. Let me know how it turns out!
