If you aren’t familiar with 3D printing, here is a video that explains the basics of it. It will change the world and there will be enormous implications for society when these printers become household items.
Gun control, for example, will be almost unenforceable because you will be able to make your own gun with this printer. People are already doing it.
What will happen to manufacturing if you can make what you need at home? Countries like China could face collapse and our own suffer, too.
Not that these printers are a bad thing; but they will change the way we live.