Davo makes a good point and reiterates one that I've tried to convey a few times. 3d printing is not going to replace the "world of manufacturing." It's a useful tool and most definitely affords us with some capabilities that we never had before. Building objects inside other objects real time is an incredible process. Few other manufacturing processes could even come close to that. What 3d printing is going to allow us to do is facilitate traditional manufacturing techniques and add new capabilities. It will become integral in the scope of manufacturing but it's not going to make every other method of making parts obsolete, ever. It's just too easy and cheap to injection mold 100's of parts per minute.

One thing that 3d printing can't do yet is work without having a flat side stuck to a plate. Even with the resin/laser/sintering 3d technologies, the part has to touch somewhere, so there is a flat spot and a directionality that has to be considered when planning the print. In many other traditional manufacturing processes, contact points and flat spots are non-existent.

So in the end non-users of the 3d printing need to understand that it's in an incredible tool and one capable of things that were only dreams a few years ago. But, it's only one new tool in the much larger tool-belt that represents the world of manufacturing. It does bring a type of manufacturing plant into the homes of regular people, but it's not going to supplant the majority of manufacturing.