From: Doug Jones (random@qnet.com)
Date: Tue Sep 26 2000 - 09:27:56 MDT
Eugene Leitl wrote:
>
> Doug Jones writes:
>
> > 670um is most of a millimeter- clearly visible to the eye! (At least to
> > my severely nearsighted eye :) Even a 670 nm arm would be two orders of
> > magnitude too large for nanotech. If you can see it, it's hardly even
> > microtech, much less nanotech.
>
> Still, it's pretty damn small for a micromanipulator as they come
> these days. What is more interesting is positioning precision -- STM
> tips are very macroscopic, yet resolve down to few pm resolution, thus
> making them clearly nanomanipulators.
True, scanning probes can achieve good 3D positioning- but to be useful
as manipulators, you need at least four degrees of freedom, and
preferably five (x,y,z, pitch, and roll or yaw). This is why milling
machines have the ability to rotate the tool about one or more axes (and
often rotate the workpiece around an orthogonal axis).
> One of the nano top down bootstrap schemes proposes using a
> progressively smaller sequence of micromanipulators, each instance
> used to build a smaller instance.
Yes, but an excessively blunt manipulator would not be able to do useful
work- rather like doing sculpture wearing boxing gloves equipped with a
single thorn. Small features could be etched on a planar surface, but
deeply concave 3D parts would be impossible.
-- Doug Jones Rocket Plumber, XCOR Aerospace http://www.xcor-aerospace.com
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