This is quoted from http://www.technewsdaily.com/6305-3d-printers-computers-homes.html .

Will 3D Printers Conquer the Consumer Market?

Jesse Emspak, TechNewsDaily Contributor

02 October 2012

The Ultimaker churns out a tiny, yellow robot figurine. View full size image

The 3D printer seems to have gone mainstream, at least for the do-it-yourself movement that populates the Maker Faire. But it remains to be seen if some "killer app" will make these printers a must-have item for consumers.
This year's Maker Faire devoted an entire tent to perhaps a dozen brands of 3D printer, many of them for sale at the faire or for later delivery. While all share the same basic functionality — they build a shape in plastic, layer by layer — they each present slight design variations.
Their proponents are enthusiastic about the printers’ potential. "It's like a new industrial revolution," said Siert Wijnia, a founder of Netherlands-based Ultimaker. "[3D printers] are where the microcomputer was 30 years ago."
To an extent that's true: in the early 1980s, it was just starting to become commonplace to have a computer in the home, and prices for top-end Apple or IBM-type machines were in the $1,000-$1,500 range, or about $2,200-$3,000 in current dollars. The 3D printers are, if anything, cheaper. Ultimaker sells its version for about $1,600. The software is open-source, and it works with most computer-aided design packages, including some available free on the Web.

Early computers, by contrast, weren't open source. So there are two questions: what is the "killer app" that gets everyone printing stuff out, and how do the various entrants compete in a market with few barriers to entry? Makerbot, the grand old man of the 3D-printer universe, has moved to proprietary software and design — perhaps an acknowledgement that it's hard to keep innovating to stay ahead of the competition with no intellectual property. [Why a DIY Pioneer Dislikes 3D Printing]

An early model 3D printer from SeeMeCNC.com

View full size image

In the meantime, the designs keep coming. The Rostock Max, for instance, gets away from the box shape typical of most 3D printers. Built by PartDaddy, an engineering company that makes machine parts in Goshen, Ind., it uses a three-armed system to move the printer head along both the horizontal and vertical axes.
The software is also different from that of other 3D printers, says Steve Wygant, CEO of PartDaddy. He is seeking $10,000 by Nov. 24 for the Rostock Max under his SeeMeCNC brand name on the crowd-funding website Indigogo. A fully assembled Rostock should sell for about $1,500, while a kit to build your own goes for about $850. Unlike most other 3D printers, the Rostock can be re-purposed as a "pick and place" circuit-board assembler, because the arms are not restricted to horizontal movement.
Wygant's background is in engineering, but it's notable how many people getting into the business come from design backgrounds. The open-source technology has become simple enough that designing and building a 3D printer isn't just the province of hard-core engineers anymore. Vancouver-based Justin Sy, for one, studied design at Simon Fraser University in British Columbia. Tinkerine, which Sy founded with friend Andy Yang, has already produced a couple of models of its 3D printer, the Ditto. The acrylic version showcases an aesthetic sense as much as solid engineering.
John Cabrer, of Tjiko, noted that the patents on most 3D printer designs have run out, which is why so many people can build them. He came up with a kit that doesn't require screws, so it can be slotted together like some IKEA furniture. "I have been doing a lot of improvements in my career," he said, referring to his background in software engineering. He added that removing the need for tools improves 3D printers by simplifying them.
So with all this enthusiasm, what are the limits? For one thing, few 3D printers print in more than one color at a time. Some can be equipped with multiple "extruders" (the part that puts the plastic down). But generally, they only come with one, so that if you want multicolored parts, they have to be assembled outside the printer. The machines also suffer from some limits on resolution, or the thickness of the layers of plastic. Generally, that is about 200 microns, or 0.2 millimeters, which is not a lot, but enough to give the pieces a rough "feel" that must be sanded down.
Then, there is the choice of plastic. Most 3D-printer makers have chosen to “go green," using a biodegradable compound called PLA, or polylactic acid. Others use a material called ABS, famous as the material used in Lego bricks. But don't expect your bricks to look, feel or work the same. The Lego company notoriously makes theirs with very tight tolerances, far smaller than a homebrew machine can achieve. The printers don’t work in metal, either, which is still the province of industrial equipment.

The acrylic model of the Ditto from Tinkerine, flaked by its wood-framed cousin

View full size image

That said, these machines can do a lot. One trick is making ball bearings, which the machines can build as single pieces. The printer creates the ring around the bearings (with a thin piece of connecting plastic that can be snapped off). The bearings aren't aircraft-quality, but for a lot of applications, they are likely good enough.
But while the thought of making one's own toys or craft projects is exciting to some, it isn't clear that a mass market for these printers will emerge the same way that it did for desktop publishing.
Cabrer said most of his sales, for example, have been to universities and schools. It's also worth noting that desktop publishing's biggest impact may have come in saving existing print publications a lot of money, because the technology eliminated the paste-up room and made it possible for smaller operations to work with big printing houses. 3D printing is certainly a big money-saver for any company doing prototyping, but the justification for its use in the home isn't quite clear yet.
That doesn't dampen some customers’ enthusiasm, though. At the Makerbot booth, where the latest models were being showcased, several people approached and asked about buying one, and at least one sought assurance that no new releases would appear before his was shipped. And at Ultimaker's stand, a common question was, "Can we take one home?"