Leonard Erickson wrote in a message to Roy J. Tellason:

 RJT> Been thinking about this stuff again,  and how technology has pushed
 RJT> all sorts of things forward,  especially in recent years... 
 RJT> Do you see this as changing,  any?  It would seem to me that
 RJT> technology ought to be able to push this "barrier" back
some,  at the
 RJT> very least. 

 LE> Well, you either have to "machine" parts, use fairly standard 
 LE> "folded" metal cases, or use "molded" parts.
And injection molding
 LE> is currently the only practical way to mold plastic plarts for many
 LE> purposes.

 LE> Alas, the molds required are fairly high precision blocks of solid 
 LE> steel. That's required by the pressures and temps involved. Which
 LE> makes them expensive.

Are solid steel molds really required for one-off or low-volume runs,  though?

 LE> There's no method that's cheap for low volume use.

I wonder,  but then I don't know enough about manufacturing processes, 
which all seem to be geared toward high-volume anyway.

 LE> The only things that even look possible are some techniques that
 LE> involve creating 3d shapes out opf liquid that are used for some 3d
 LE> modeling work (modeling in the scientif/engineering sense, not the
 LE> hobby sense). But so far they are very fragile.

Materials science seems to be making large strides forward in recent years, though.

 LE> And, of course if they ever get molecular assemblers/fabricators to
 LE> work, all bets are off. No, this isn't "nano-technology". At least
 LE> not in the normal sense. These would be "normal" sized devices that
 LE> build objects one atom or molecule at a time.

The people who make chips and such stuff are bumping into limits all the
time,  and figuring out ways around it.

I was reading something just in the past day or two where they were talking
about fabricated "holders" or "channels" for the
*molecules* of some organic catalyst that would otherwise degrade too
rapidly,  something involved in the processing of DNA.

 LE> "Real" nanotechnology involves devices the size of large molecules.

Yeah.  Nifty concept,  that,  but I still think we're a ways off from that.
 Too much "macro" thinking is being applied to it,  and when you
get down to that sort of scale,  physics is different!

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