From:          jmk@iquest.net (Jeff or Verna Lynn)
Subject:       Stereolithographer

Here's a little something I did this morning....Found it in an old issue of
Discover magazine (Sept94 p22).  (Can we get this into Ultra-Tech II?)


Stereolithographer
Also called a Fabricator or "Fabber," the stereolithographer uses a vat of
liquid polymer and a laser to recreate three-dimensional objects.  It
converts a digital computer file into a 3D object by "printing" the object
one two dimensional layer at a time.  It's raw material is a liquid polymer that
hardens with the laser shines on it.  The laser breaks apart certain molecules
in the liquid, transforming them into a kind of glue that binds the polymer
chains together, solidifying them. To print a drinking cup the laser first
prints a solid disk of material. The object is lowered slightly (about 1/5000th
of an inch) to allow a thin wash of polymer to coat the disk and the laser then
prints a circle, the object lowers again and again until the cup is the correct
height. By printing one cross section at a time, a stereolithographer can print
object much more complex than cups!  Linked to the appropriate type of scanner
(any device that maps and stores surface data) the "Fabber" becomes a 3D-copier.
 CT scanners, radar or ladar can all be used with the Fabber. If the scanner and
the fabber are separated by great distances, you get a 3D Fax machine! At TL7,
the Fabber only works with polymers, creating slightly translucent plastic
objects. Late in TL7, soft metal objects can be Fabbed   At TL7 the Fabber costs
$200,000, and weighs 100 lbs and takes up .5 cy, plus the cost, weight, and
volume of the computer/scanning system.  Refills are $100 per gallon of polymer
or pound of metal paste.  In addition, the Internet becomes a great source of
Fabbed objects.  Webpages will feature .ZIPs of famous sculptures, scaled-down
scans of Jennifer Aniston and Marina Sirtis and newsgroups like
alt.binaries.fabs.erotica allow all manner of ill-thought scans to be used as
bookends and paperweights. At TL8, it can use various "metal pastes" to recreate
steel nuts, bolts and hinges and "semiconductor paste" to create printed
circuitry.  The machine costs $75,000, weighs 50 lbs and has a volume of .25 cy.
They are a common in schools, factories and some retail stores.  At TL9,
nanotech replaces Fabbers completely.