Investors and futurists share a common cause. Both try to secure their future by predicting the future -- but as you've no doubt discovered, it can be difficult to keep your head in the midst of outlandish expectations. Many a bubble has been blown by investors leaping into a new technology without understanding how technology really grows.

Is 3-D printing in such a bubble? With only a few profitable public companies to invest in, it seems unlikely. However, 3-D printing is very much an industry of the future, and much of its current hype is built on the promise of a transformative future. Will that promise be kept? No one can say for sure, but we can at least investigate how realistic it truly is. Where will 3-D printing be in a decade? The present offers some clues. Let's take a look.

A 3-D printer in every home
You probably have an old-fashioned ink-on-paper printer at home, and don't think much of it. There was a day, not 25 years ago, when such printers cost over $1,000. Hewlett-Packard (NYSE: HPQ) achieved great success with its line of low-cost DeskJet printers after finally cracking the $1,000 cost barrier. Now, you can print out just about anything you need, even in color, on printers that often cost less than your monthly Internet bill!

Some 3-D printers are already toeing that line. The 3D Systems (NYSE: DDD) Cube, one of the first true plug-and-play 3-D printers aimed at consumers, costs $1,300. I compared the Cube to a top-of-the-line Stratasys (Nasdaq: SSYS) from the past decade earlier this year. You can see the side-by-side statistics here. If you'd rather get a quick and dirty rundown, the same 3-D resolution that once cost over $300,000 can be had today for less than 1% of the price.

However, 3-D printing is not the same as printing to paper. The Cube is limited to a single jet of tough plastic within a maximum 5.5 inch cubic print space. That's enough room to make Legos and small toys, but what about for those occasions when you might want to create, say, customized ceramic dinner plates, or a new wallet?

The cost curve of these printers over time implies that single-plastic-based 3-D printers are likely to cost $100 or less in 2022. What about multiple-material consumer printers? One recently introduced "desktop" model, built by recent Stratasys merger-mate Objet, can print with seven different materials and should cost about $43,000. If this sort of device follows the same cost curve as the other printers, I'd expect consumers to be able to pick up multiple-material printers in 2022 for about $500. Will these printers have enough material diversity to make dinner plates and wallets? I'm not sure, but there are a few things I know they'll be able to make…

Cupcakes on demand
If you've ever seen one of several dessert-designing reality TV programs, you know how much artistry goes into those elaborate cakes and ornate chocolates. With the right material, and the right recipe, anyone can become a cake ace. And why stop there? You could print out a chicken nugget in the shape of an actual chicken, or create the perfectly planned plate every time.

A Cornell University researcher has already developed such a printer, capable of printing out anything from chocolate to celery. Want some seafood? No need to go to the market -- just print out a dollop of scallops from a tube in the fridge. Such a device should find a home in confectionaries everywhere, and could eventually replace much of the assembly-line process required to make fast food.

Printing food this way could also help eliminate a tremendous amount of waste -- conservative estimates peg annual American food waste at over 100 billion pounds per year.

Printing a better human
The possible 3-D printing applications for the human body are nearly as diverse as the human body itself. The technology has been in development for years, and might someday print out donor organs using the patient's own cells. Also known as "bioprinting," the technique has some big backers, but there are some under-the-radar companies making inroads as well. Organovo has already developed a commercial bioprinter, with the ultimate goal of printing replacement organs.

Bioprinting has other applications as well. Organovo has sought partnerships with drugmakers, who could test their medications more directly on printed tissue. Johnson & Johnson (NYSE: JNJ), which has a stake in a different bioprinting endeavor, could make use of this testing technique. That company's medical diversity brings other medical applications to mind as well, starting with replacement limbs.

Bespoke Innovations, which 3-D Systems acquired last month, can create customized prosthetics, designed by those who'll use them to reflect their own individuality. Other printers can create replacement bones, such as one popular case where an elderly European woman received a completely 3-D printed replacement jaw.

You might even pick up customized drugs made by a 3-D printer in 2022. Earlier this year, Scottish researchers modified a currently available 3-D printer to do micro-scale chemical engineering, which could greatly reduce the development time (and thus the cost) of many drugs. Cancer-drug makers like Dendreon (Nasdaq: DNDN) might reach wider audiences in a shorter time by combining bioprinters with 3-D chemical printing. That would certainly help investors, who often sit through years of misery before a drug's potential pans out.

Foolish final thoughts
These are just a few of 3-D printing's potential applications. The technology might also one day be used on a massive scale to create buildings, or on a tiny scale to create electronics. Collaborative communities are already busily designing all manner of fun or functional 3-D printed products, which you can order online from design repositories like Shapeways.

It's easy to get carried away with elaborate predictions when looking at 3-D printing's developments. It's also difficult to constrain one's imagination when so many brilliant people are working on pushing the boundaries of 3-D printing out to the very edge of human potential. One estimate pegs the 3-D printing market's size at $5 billion in 2020, but that may underestimate its potential. After all, there was "a world market for maybe five computers" in the 1940s. This technology is further along than the ENIACs of those days, but it's got a long way to go to reach its potential.

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