Susie Prototyper

Ideally, the concept of "on demand" shouldn't limit itself to pay-per-view movies. If 3D printers were widely available in every household, consumers could quickly "demand" and fabricate specialized food and other objects at the touch of a button. Scientists in the emerging field of "bioprinting" are even attempting to make it possible to "print" custom-made biological tissue from a patient's own cells.

According to Cornell University Professor Hod Lipson, 3D printers are reaching a "tipping point" where they will become affordable, accessible, and versatile enough to reach the average consumer.

This idea is certainly appealing — widespread availability of such technology (and an understanding of how to use it) would spark the rise of personal manufacturing and encourage innovation. But will it happen anytime soon?