Future of 3D printing

3D printing has all the signs of being a genuine disruptive technology. 30.000 feet high there are four major areas where I see 3D printing has impact:

1. Personalized products and personal fabrication
2. Reduction design-to-manufacturing cycle
3. Bring back manufacturing to the Western world
4. Manufacture parts which were not possible before

Personalized products and personal fabrication
3D printing makes it possible to do one-off unique parts production. Because of this it is possible to personalize products based on taste or function (think clothes). Embedded in this is also the option to make your own things. Just think hobbyist who want to create stuff for their hobby like model train models which are not sold by any of the major manufacturers.

Reduction design-to-manufacturing cycle
Mass produced products contain mass produced parts. These parts are produced in very high volume to make them cheap. To change the design of such products takes at least the cycle to retrofit existing production lines. The time to do this can take weeks to months.
Using 3D printing it is possible to make immediate changes and put them in production. The cycle is then reduced to left-over stock but could be brought down to days.

Bring back manufacturing back to the Western world
Manufacturing has mostly migrated away to low-income countries. Since 3D printing is a mostly automated production process there is no need for low income machine workers to make the production cost efficient.

Manufacture parts which were not possible before
3D printing allows for manufacturing parts which were not possible before. The most practical application I have seen up until now are ceramic filters and special molds for iron/steel casting processes. I think this area is currently very much under valued because a lot of engineers / designers are not ware of the capabilities yet.