Who wouldn't want a machine that can make almost anything? 3D printing is useful for manufacturing because it is an additive process. It lets you make personal parts and gives you the ability to build quick prototypes.
3D printers are practical because 3D printing is an additive process. In other words, instead of starting with a block of material and shaping it until you attain your part, with 3D printing, the machine builds your part one layer at a time from the bottom up.
For the same price, and with the same machine, you can make personal parts. For instance, you can have a toy with your name on it and I can have a toy with my name on it for the same material cost.
Another useful application of 3D printers is the ability to make quick working prototypes. You can think of a product, design it on a computer with a CAD program, print and hold your idea in your hands.
3D printers are terrific for people who like to make things. The ability to hold your thoughts in your hands is going to change the manufacturing industry.
