3D printing hasn’t always just been “3D printing” - the processes and machines we know today started out as part of the open-source RepRap project and by being able to print improvements for themselves and even entirely new machines, over time, only the best approaches survived! Adrian Bowyer initially started the RepRap project and nurtured it until it was large enough to sustain itself from community contributions. Here’s why he chose 3D printing for self-replicating machines and what he’s up to now!
https://www.youtube.com/watch?v=VV0Tjwq7Uc0