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Envisioning the Desktop Fabricator
mkl writes "Yesterday I fantasized about a generator of matter. Not a laser plotter for carving 3d objects, but a device that will assemble any given object from its base, out of atoms. I was thinking about a device that can find its place under the roofs of all the people working on PCs all over the world. So I fantasize about it at work and what do I see in the Wired News newsletter? 'Any product, any shape, any size -- manufactured on your desktop! The future is the fabricator.' Heh."
First post to mention The Diamond Age : Or, a Young Lady's Illustrated Primer (Bantam Spectra Book) by NEAL STEPHENSON. All about nano-tech and fabricators and stuff.
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I saw a prototyping machine at a recent trade show, that could lay down ABS plastic. For a six cubic inch toy wheel, it was an overnight job. It wasn't neceessarily a desktop unit, it was still considerably larger in footprint than an HP LaserJet 4, and is floor standing, I think.
It also costed $25,000.
The machine type described are good for prototyping and custom parts, but there are usually better mass production methods. Laying down atom-by-atom will be slow for a loooong time and at best be of most consequence to nanomachines for that time.
Go read Drexler's "Engines of Creation" for the classic "nanoassembler" hype. The idea of pushing atoms together is neat, but it's hard to do. Free-floating nanoassemblers are still a fantasy. I expect to see nanoassemblers, but they'll probably be more like scanning tunneling microscopes made on an IC substrate and used to read and write DNA. Making big hunks of solid materials that way is too slow. Look at how long it takes to make a tree, or a coral reef, or a pearl. (Admittedly biology is power-limited. In a manufacturing environment, you can run external power into the nanomachines and remove that limitation. But that won't work for the free-floating nanomachine concept.)
If you have a good milling machine, you can make almost any solid shape you want. I know four people with milling machines at home. Two of them have good computer-controlled mills with all the necessary software. Yet they don't actually make all that much. One of them is building a steam engine, and he's been at that for years.
Then there are stereolithography machines. The newer ones work fine. You can now make things out of ABS and nylon, which are tough enough to be useful. This is a big improvement over the early models, which made only soft wax models nice to look at but useless.
It's a very slow way to make stuff. In the real world, almost all consumer products, with the notable exception of wood and fabric products, are made by some kind of cheap moulding process. There are dozens of such processes, from die casting to injection moulding to progressive stamping, but they all involve forcing material into a mould. This is an incredibly cheap process in quantity, and is why manufactured goods are so cheap. Very few consumer items are made by machining down a solid hunk of material.
Even ICs aren't made by direct writing. It's quite possible to make ICs with direct-writing electron beam machines. This eliminates the need for masks, and every IC can be different. Works fine. Useful ICs have been prototyped that way for years. Too slow to be commercially feasible.