Making solid 3D-printed connections

When you print with a 3D printer, regardless of the material you are using, there will be swelling and shrinking. When printing, the material moves around during the printing process, and everything expands and contracts as materials cool or cure. While it would be great to think that a 1” 3D-printed peg will fit perfectly into a 1” 3D-printed hole, that is rarely how it works out. Generally, you need to allow for some additional space between printed parts to account for material expansion during printing.

I have heard multiple reports from multiple parties on the best gap to include in mechanically connected parts when printed but I’ve found that the best way to find out what kind of gap to use is best determined by testing your own printer. To that end, let’s make this quick test model:

Figure 6.19 – 3D-printed connection test

With this simple test, you can quickly test what amount...