When Christoph designed, printed and load tested version 1 (the second version) of the makeSEA brushless motor, he had some concerns about how many RPMs the rotor could sustain without breaking apart. As you know, 3D printing is not an exact science, and even the smallest anomaly or detail can cause wobble that at the very least, negatively effects efficiency and at the worse, results in magnetic projectiles careening through your workspace.
This brings up another question; he mentioned that the strength limits of the PLA and PTEG he used to print the rotor are worth exploring, particularly in relation to the weight of the magnets and RPMs. I'm curious if any makeSEA members want to share their own findings. If so, please do so below. But remember what they say: It's all fun until someone loses an eye, so be careful out there.
If you want to check out how efficient Christoph's 3D printed motor was in the end, check out his extensive entry on the makeSEA 3D printed brushless motor on the reference wiki.