Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!noc.near.net!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!world!jamcorp
From: jamcorp@world.std.com (Jonathan Priluck)
Subject: RE: orders of magnitude cause big problems
Message-ID: <CC1pB1.D73@world.std.com>
Organization: The World Public Access UNIX, Brookline, MA
Date: Fri, 20 Aug 1993 06:42:36 GMT
Lines: 85



Return-Path: <lammens@acsu.buffalo.edu>

In comp.robotics you write:

>1) Feeding in raw material, this cannot be done through an
>electronic interface, raw material must be introduced into the
>system somehow.  One option is to use larger machines to produce
>scaled down "stock", for example .001 wires would replace 1" rod
>and thin slices of sheet metal would become "bar stock".



Can you actually turn .001 wires in a lathe at high speed without
themswinging all over the place and still taking the pressure of
the cutting tool? I am amazed. I guess the trick is using very
short pieces of very thin wire.

     Thats the idea, for the most part you would not be dealing
     with anything longer than .01 .  It's the RATIO that matters,
     not the actual thickness.  I would be amazed too, we have not
     actually done this yet; I apologise if I gave that impression. 
     What we can do with such wires is weld them to eachother and
     build tiny structures, in fact we are excellent at this.  I
     can build you a 100 storey steel frame "skyscraper"  which is
     just one inch tall and perfectly to scale.  The location of
     the "beams" and "girders" which it is made of are located to
     a tolerance of +or- .0001


>4) Tolerances.  This is a MESSSSSSS I don't even want to get
>started, its like a catch 22.  You need small machines to make
>parts to high enough tolerances but you need the parts first so
>you can build the machines to make those parts.   AAAAAAAAAARRRRG
>picture me sitting at my desk pulling my hair out :^)  >  

I get the picture. Perhaps you'll have to resort to an incremental
approach: making the smallest possible parts with the desired
tolerance on normal size machines, use those parts to build smaller
machines, use those machines to build yet smaller parts, etc. This
may take a long time, but it should work. Perhaps you should hire
some old-fashioned Swiss watchmakers too :-)

     That is essentially the plan.  I think that, while it is
     tedious, at least wherever we stop, what we have done to that
     point will be very valuable; even if we cant progress down to
     the next smallest size.  So if we get stuck with a 7" tall
     milling machine at least we will have that, and will be able
     to make things no one else can using it.  
          But what about alternate machineing methods. It may be
     neccesary to use something other than a cutting tool to
     acheive the sizes we want.  One fellow suggested chemical
     machining and elctro-discharge machinig as options where the
     "tool" does not put any pressure on the work piece.   What do
     you think about an alternate approach?  Do you think we should
     be stubborn and stick with the incrementals?  
          I'll tell you what got us started on this;  we kept
     reading about K.Eric Drexler and his "nanomachines".  We were
     talking about them one day and though "thats nice in theory,
     but in practice the smallest things we can *actually* build
     now are watches", then we went on something like "how about we
     forget about nano (for now) and just try to go one step
     smaller than a fine swiss watch".  See what I mean, then we
     started working on it <exasperated look: again picture me
     tearing out tufts of hair :^); unless it happens through
     genetic engineering I don't think you are going to be seenig
     any *real live* nanotechnology any time soon.  
          On the other hand I think we have a good chance of
     success on the first and second step down from the swiss
     watch.  Even the first step down would be enough to make a
     robot small enough to fit inside some of the larger blood
     vessels.  And the second step down could go almost anywhere in
     the body (anyone see the movie Inner_Space with Dennis Quaid). 
     There would be millions of applications for such "millibots"
     (thats millimeter scale) and even more applications for the
     next generation.  What think ye sci.robotics net-folk? 


Regards, Jon Priluck
-- 
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