Disclosure: I have seen a set of 3d printed x-y motor mounts, like these from jimmit on thigiverse, but no 3d printed z (up-down) mechanism. Here’s is my prototype z-axis mount (right). It is the grey ...

Most 3D printers use stepper motors to control the movement of the extruder head. If you could actually print those motors it would be one more big step toward self-replicating hardware. Now obviou… ...