3d printing

3d printing is "a process for making a physical object from a three-dimensional digital model, typically by laying down many successive thin layers of a material: if you use 3D printing for prototypes you will simply be able to go to market faster."

it can  be used to make guns,bullets,and pretty much anything in just a good amount of time 

3d printers could dramatically change our society because every thing will be made a lot faster

they can be affordable by the average person but they may not get a good one