If you've never heard of additive manufacturing, there’s a better chance you have heard the more colloquial term for the same thing: 3-D printing. What many people still don't realize is that there’s much more to this relatively new technology than pedestrian uses like making key chains and kitsch. As the concept is rapidly developing in factories and basements alike, people are now making things like molds for moving parts and tools, medical devices and all sorts of other items. Each day the concept is increasingly shaking up industry as we know it. So let's take a look at 3-D printing - and what these increasingly accessible devices are being used to make.

How 3-D Printing Works

The concept most often referred to as 3-D printing earned the name additive manufacturing because it is a unique manufacturing process that involves creating a solid object, where material is added rather than removed. Traditional manufacturing of a singular solid object typically involves the removal of material; think carving wood, bonding plastics or filing and welding metals into shapes. In the 3-D printing process of additive manufacturing, a digital file made with a CAD program on a computer transcribes instructions to a desktop device - the "printer" - which adds individual layers of material in a highly accurate and precise manner so as to produce a three-dimensional replica of the digital file. Printing an item often takes between 20 and 40 minutes, but it can take as long as 24 hours. So for some items, you may want to print yourself a popcorn container, which is exactly the sort of thing most 3-D printers could make.

How Printing Went 3-D

As an emerging technology, additive manufacturing is only "emerging" in the sense that it is coming onto the scene very strongly of late. However, the concept and technology have actually existed for 30 years. It's much like the technology for tablets and smartphones, which existed for quite some time before these devices became ubiquitous items in most American homes. After all, it often takes time for technology to develop adequately to be sold to consumers - and to become inexpensive enough for a broad range of consumers to afford it. The necessary technology for 3-D printers - such as the lasers involved - simply didn’t fully come into their own until the 2000s, when open-source projects and other initiatives helped further develop the technology.

Who Uses 3-D Printers?

The thing that makes 3-D printing so exciting is that at least in theory, this type of manufacturing could be used to make almost anything - including functioning human organs. It has been used - mostly experimentally - in the automotive, aviation, manufacturing, medical and do-it-yourself industries. Major manufacturers, for example, are using 3-D printing for various cost and time saving-reasons.

"Marketing departments are the customer. They purchase these printers for several reasons. Often, a customer is unable to visualize what a finished product will look like. It is extremely helpful for them to be able to hold a prototype in their hands," said Scott Cleveland of Impac Systems, a 3-D printer reseller.

This makes sense when considering the ease and savings of designing a prototype in plastic rather than whatever more costly materials the final product might actually be made of. Some companies also adopt this manufacturing technology for reasons of sheer physical practicality.

"The products offered by oil and gas companies tend to be extremely large. If they were to take the finished product to a trade show, it is way too heavy," Cleveland said. "Today, many print off scaled down prototypes that they can easily display on a table."

But the world of home 3-D printing has grown quicker than a kid's LEGO castle, which, by the way is something many people now print off for their kids. Good, old Web 2.0 crowdsourcing is largely responsible for the growth of 3-D printing. There are numerous websites where people sell their own manufactured products, blueprints of those products, or they simply share the blueprints in an open source fashion. Shapeways.com and Thingiverse.com are two such popular sites. (Read more about crowdsourcing in Crowdsourcing: What It Is, Why It Works and Why It Isn't Going Away.)

Oh, The Crazy Things People Print

The whole concept of 3-D printing is without a doubt part of a broader trend in the growing do-it-yourself movement, which has been going on in basements and workshops for decades. While professionals use 3-D printing technology for industrial design, architecture, engineering and more, the barrier for people to produce homemade products as hobbyists can be as low as $400 for some printers. That's about the price of a decent mountain bike. Plus, if you go with the printer, you might just be able to print up the parts to build your own mountain bike.

Although the middle market for 3-D printers is about $2,000, this still puts these devices well within reach of a hobbyist designer, like the popular selling MarkerBot Replicator 2, shown below.

Plus, data and engineering folks will have no lack of methods and terminologies to crunch on as they throw themselves into the 3-D design learning curve; terms like "polygon count reduction" and "ABS plastic" and "PLA plastic" are the norm.

Makerbot Replicator 2, Makerbot.com

The creativity of the designs for 3-D printers seems to know no bounds, from homemade game pieces and iPhone cases to, well, nuts and bolts (literally). Here are a few amazing examples.

Make your own glasses with a design for these Marcello Specs, Vertdesign.com.au

Play around with this $1,600, 17x17x17 Rubik's cube from hell, Shapeways.com

As I browsed the virtual aisles of these 3-D blueprint sharing sites, I couldn’t help but smile at the numerous whimsical items people were clearly making not for the masses, but for themselves. Like this Super Mario Mobius Strip:

Super Mario Mobius Strip, Shapeways.com

And here's one more thing people are starting to make at home: sex toys. Tom Nardone, founder of MakerLove.com, a free site offering designs for homemade sex toys, explained the privacy benefits of home production of items that many people find embarrassing to buy.

3-D Printing Controversy

But with all the feel-good things people are printing up at home, there's also controversy around 3-D printing, because not everyone is printing up harmless sex toys and hip eyeglasses. For one thing, numerous hobbyist are making blueprints - and actual print outs - of products that are patented, which infringes on the patent owner's rights. A quick search on many torrent websites known for underground and sometimes seedy file trading reveals a growing number of shared designs for patented items. The infringements likely won’t ease up anytime soon, especially now that scanning objects with CT scanning apps has made it so easy to instantly translate 3-D objects into a digital file.

But what's even more controversial - especially as the U.S. struggles with gun control legislation - is the ability to print fully functioning plastic firearms. By most accounts, the quality of these firearms is questionable, but they do present problems if legislators decide to implement legislation to increase gun control in the sense that there's very little that could be done to prevent the proliferation of home-printed weapons.

The Future of 3-D

As people develop new products for 3-D printers everywhere, it won't be just the products themselves that change the landscape of things, but the concepts derived from the practice, such as crowdsourcing, a shift toward do-it-yourself manufacturing, and the sheer creativity of the applications that hobbyists and manufacturers come up with. The fact that 3-D printing technology is essentially wide open and accessible is both its greatest benefit and one of the major challenges it'll face when it comes up against patent laws and other restrictions - not to mention the considerable might of the manufacturing industry. But while only a few years ago printing up your own products rather than buying them in the store was totally inconceivable, it is increasingly becoming a more realistic option. As with any breakthrough technology, the results are sure to be cool ... and perhaps a little complicated.