Why your part broke: it was the orientation
A printed part is up to five times weaker along the stacking direction. How to design and orient so the load does not peel the layers apart.
3 min read
A printed part is not a homogeneous block: it is hundreds of layers glued together. Within a layer the plastic is continuous and strong. Between layers there is only a weld. Guess where it breaks.
The classic case is a hook or bracket printed upright: it looks perfect, survives a couple of uses, and one day snaps at the base, cleanly, along a single layer. Laid flat, the same part takes several times the load.