>>http://www.youtube.com/watch?v=ZboxMsSz5Awefore
>
>I'd seen this before. Two things skipped over:
>(a) How does the scan, in itself, decide which are the moving parts.
>(b) How long the does the 'printing' take.
>
>I see a couple of 'printers' (in kit form) available for less than $1000 but I assume the 'ink cartridges' are expensive.
>
>Also wasn't too impressed with the demonstration of the strength of the resulting 'print'......
>Sorry about all the quote marks.......

The simple external scan they demonstrated can't decide about the moving parts - especially the details of hidden moving parts. Clearly the scan was tweaked so the adjustable portion of the wrench would work in the finished product.

I'd bet the time required is long. Much longer than cycling a hot metal blank through a hydraulic press.

There's (to my mind) a more impressive demo of the technology at http://www.techeblog.com/index.php/tech-gadget/fully-functional-bicycle-made-with-a-3d-printer . It's very impressive they were able to build a bicycle that could be ridden for even a few meters. The video shows they had trouble with the bearings. Nylon has got to be an awful material for antifriction bearings - it has probably less than 1% of the strength of steel ball bearings, and if you get the bearing humid, much less damp or wet, it will absorb water and swell, so your tolerances go out the window. Also, with a 3D printing process you can't press-fit or otherwise preload a bearing to avoid the stress reversals that will kill the rolling components in no time.

It's interesting the first video uses a proprietary powder with a chemical "binder", while the second uses nylon in a sintering process. Theoretically, using metal powder and higher temperatures you could 3D print metal parts with a sintering process, which would be much stronger than either.

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