Lex Lennings wrote:
> The idea is fascinating, a great deal of which is caused by the visionary
> subject line that you use: one day RP will be just as cheap, easy to use
> and generally accepted as popcorn.
Dear Lex,
A bubble growing from a microscopic laser-made defect has a natural
leveraging of means that might bring that day closer. The computer and
laser, in effect, only scribble orders when programming foam---the grunt
work is done later by ordinary oven heat and the energy of compressed
vapor.
For some guestimates assume we wish to program foam by laser pitting a
100-micron thick polymer film (which will then be wound up for puffing.)
Assume the pattern of pits averages 100 micron spacing on a square
grid---this gives 1E9 pits/liter before puffing. If we puff to 5:1 in
volume, the foam has 200E6 pits/l.
Assume each pit has a volume equivalent to a cube 10 microns on a side,
or 1E-9 cm3. Assume the laser energy cost of such a pit is 1000 cal/cm3
( 4200 J/cm3.) Each pit then requires 4.2 E-6 J, and the 200 million
pits in a liter of foam requires 840 J.
Under these assumptions a 1kw laser pulsed at 200 MHz could program foam
at one liter per second. Ordinary-sized parts could be programmed in a
few seconds (of course the heating/puffing step would take much longer.)
This is about three orders of magnitude more productive than methods
that make the laser do the actual work.
Jim Mallos
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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