From: sinster@scintilla.capitola.ca.us (Darren Senn)
Newsgroups: sci.nanotech
Subject: Re: Rere:Snowballing tomk
Date: 31 Aug 92 19:24:10 GMT

In article <Aug.26.22.27.43.1992.1276@planchet.rutgers=edu> kr%portal@cup.portal.com writes:
>-> ..., but it won't be
>->in our lifetimes that we see mass production of common objects through
>->atomic or molecular assembly.  ...
>
>This of course depends on how old you are. Even given the uncertainty of
>time estimates, it does seem fairly reasonable to assume that within
>roughly two decades a well developed nanotechnology will be available

No, I don't think that's reasonable.  I'd estimate at least a century
before nanotechnology is mature.  Of course, as you pointed out, time
estimates are uncertain.

[...]
>On the other hand, some people seem to be actually questioning that
>advanced manufacturing might not be possible to the full extent, so let
>me please deal with that first.

Oh, I'm utterly convinced that nanotech is possible.  100%.  Neither do I
believe there has to be short term incentives for it (what do you think
Bell Labs and the NSF exist for?).  What I'm arguing against is the
argument that nanotechnology will be the manufacturing messiah, and
it's coming in 2012, Hallelujah!  :)  We can only say that nanotech
_might_ be all that.

>One way of building large macroscopic structures is outlined in EoC
>on p.60 using a rocket engine as an example. You essentially build a very
>thin scaffold using not a lot of material and then you fill in the rest
>of the material in a highly parallel fashion all along the scaffold.
[...]

You are using the assumption that:
	a) You have a large number of assemblers, and
	b) The assembler technology is such that many of them can work on
	   a single project at a time.
These assumptions are valid for a mature technology, but we've got to
get there first.

The first many iterations of the technology will likely use assemblers
that are large, expensive devices containing chambers with tightly
controlled environments within which the assembly occurs.  You will
not be able to use a couple moles of these assemblers on a single
project.  In fact, a couple moles of these assemblers will never be
constructed.  Maybe as many as 200, and certainly no more than 10 or
12 in a large specialized company.

[...]
>By equipping an AFM with multiple antibody-tips [...]

This is a very strict precondition.  I'm given to understand that we
can't do this now.

>[...] which are able to grasp
>organic molecules, positional chemical synthesis could be performed
>with the possibility of performing 10^5 consecutive chemical reactions
>on one substrate. With proper design, this might suffice to build a 
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>very crude protoassembler, which is nevertheless capable of synthesizing
>something by following a string of commands, for example a copy of itself.

That's another strict precondition.  I have no doubt that the problem's
solvable, but remember that it has to be solved _before_ we can start
bootstrapping anotech.

>[...] The costs for the chemicals out of
>which the assembler is built (these might have to be thrown away, not the AFM),
>even if those are very expensive compounds, are negligabl$, as next to no
>material is consumed in the initial stages [...]

What about R&D?  This is by far the most expensive part of product development.
Do you know how expensive it was to design even simple compounds like nylon?
Its tremendous usefulness is the only reason that DuPont was able to make a
profit on it.  Organic chemicals are very expensive and very difficult to
design.  Your argument that the costs for the chemicals will be small is
probably correct, but that doesn't make the technology inexpensive: early
manufacturing costs will be increased to cover the R&D cost.

-- 
Darren Senn                                    Telephone:       (408) 479-1521
Internet: sinster@scintilla.capitola.ca.us         Snail:    1785 Halterman #1
"... but why did it have to be made of sandstone?"        Santa Cruz, Ca 95062