On the Fast Company site, Jamais Cascio reviews the rapid progress being made in desktop manufacturing:
Take a design for a simple product–an engine part, for example, or a piece of silverware, and feed it into a computer. Press "print." Out pops (for a sufficiently wide definition of "pops") a physical duplicate, made out of materials plastic, ceramic, metal—even sugar. Press "print" again, and out comes another copy–or feed in a new design, for the next necessary object.
It may sound like a scene from a low-rent version of Star Trek, but it's real, and it's happening with increasing frequency. This process goes by a few names, but it's most commonly known as "3D Printing" (the older name, "rapid prototyping," no longer captures the range of uses, while the other alternative name, "fabbing," is a little too cyberpunk for the moment). While the process has been around since the mid-1980s, the cost of 3D printers has been dropping quickly, and now range to well under $10,000. If that still sounds like a lot of money, you're right–but don't forget, it was when laser printers dropped to this price range in the mid-1980s that the desktop publishing revolution kicked off.
Right now, most 3D printing is limited to single-material objects (as designer Sven Johnson noted on Twitter, we're now starting to see two-material 3D printers). Most systems use (often proprietary) plastics, but a few use metal "toner." The latter is turned solid by a variety of high-tech means, from sintering with lasers (for simple objects) to using high-energy electron beams to melt the metal into dense, high-strength parts.
On the near horizon, however, are systems that would allow for multiple material inputs, and those that allow the use of electroactive and electronic polymers. Although plastic electronics fall way behind traditional silicon processors when it comes to speed, they're moving into the "just good enough" category, raising the tantalizing possibility of being able to print out basic electronic products–sensors, RFID-type tags, even simple communication devices–by the middle of the next decade.
As the technology improves and prices fall, Cascio forsees a world in which "the kinds of personalized products now available to those with the right money and know-how may soon be available to everyday people." Needless to say, this could bring the same sort of disruption to manufacturing that we've already seen in the news and entertainment industries. But it also "offers the potential for the ultimate 'maker' culture, where commercial products are bought off of iTunes-like online stores and printed at home, while eager hardware hackers play with design tools and open-source hardware systems to make entirely new material goods."
Caveat: My knowledge of this subject is limited to what I've read in Cascio's article and in Neil Gershenfeld's equally enthusiastic book Fab. If you've got a more skeptical take on the tech's prospects, please share it in the comments.