Mass 3-D printing is VITAL for space colonization as it allows a single manufacturing machine that can make multiple different complex parts.
All you need is a smelter/refiner machine to make the feeding materials for a 3D printer and you have reduced the sheer amount of material you would ever need to ship to a colony on the moon or mars.
So instead of needing ship tons and tons of finished product to a colony, you would only need to ship the 3-D printing machine and the smelter/refiner machines. and even some 3-D printing machine are being made that can make parts for even bigger 3-D printing machines, so the only thing you need to ship are the parts that cannot be made by the 3-D printer yet.
Fantastic idea.
Send a small machine, that makes bigger machines.
Build your own mining machines right there.
use the mined material to make more
That must be why all the time travelers from the future all report houses that look like domes. Easiest shape to print and strongest too.