Surely everyone on this list has seen the art by Bathsheba Grossman ( http://bathsheba.com/), who pioneered turning this form of fabrication into an art form. More recently, Shapeways (http://www.shapeways.com/) has become the one-stop shop for quick and cheap 3d printing of any design you create in your material of choice. You need to be somewhat cautious of the plastic home 3D printers, though. The high-quality techniques like those that print Bathsheba's art generally involve laying down a layer of your building material and selectively sintering together the bits of it that you want to remain in the final product. The home plastic ones just involve laying down the parts you want, but without an automatic support structure covering the rest of the printing bed. This means you can't necessarily have overhangs with slopes larger than 45 degrees, various types of disconnected cross-sections, and so on. (These things may still be possible, if you're willing to add support struts into your 3d model and break them away afterwards.) Anyway, it is indeed an amazing technology... --Michael On Sun, Aug 14, 2011 at 9:20 AM, Henry Baker <hbaker1@pipeline.com> wrote:

FYI -- Metal 3D printers are very expensive, but plastic 3D printers can be built at home by hackers (see Maker Faire) for not a lot of money.

I recently heard a talk about this technique, which enables the direct production of a metal part using 3D printing ("additive manufacturing") technology. One German company can even build _titanium_ parts using this technique.

The important thing about this technology (in my opinion) is that it allows the production of parts that could never be manufactured _any other way_.

For example, if you want to save weight in a part, you can "drill out" portions of the metal that contribute to the weight, but not to the strength. But this process is quite limited, because there are many places you can't get a straight drill hole, and many places where the drill holes would be far too small to actually drill.

You could, however, build something like a bicycle crank as a lacy, fractal structure with microscopic holes _everywhere_, which would weigh 1/2, 1/3, or less than a standard crank, but without giving up any strength. Human bones are similar in structure: if they were _solid_, bones would weigh far more than they do for the same strength.

So far, the only thing missing from this picture is the incorporation of very strong fibers -- e.g., carbon fibers or even carbon nanotubes -- which could provide even more strength with less weight.

Ideally, one would like to incorporate both types of technologies at the same time -- i.e., a kind of "weaving" machine hooked up to a 3D printing machine.

In any case, get ready for a true revolution in strength/weight ratios in new materials & manufacturing technology.

http://en.wikipedia.org/wiki/Direct_metal_laser_sintering

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