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3- D printers or Fabbers - the first glimpse of a
Magazine: Discover
Issue: September 1994
Title: Technology Watch, Printing in 3-D
Author: Scott Faber
This Discover article is brought to you courtesy of AT&T.
A new machine called a fabber lets you print out computer graphics in
3-D, make plastic copies of solid objects, and even fax them.
EVER SINCE GUTENBERG first got the presses running back in 1453, people
have been spreading their ideas far and wide through printing. Now there
is a new type of machine that makes it possible to print solid objects
as well. The machine is formally known as a stereolithographer (which
means "three-dimensional printer"), but to its friends it is a fabber
(which is short for "fabricator"). Fabbers are already in use as
stand-alone printers and as the nucleus of three- dimensional copying
machines. Three-dimensional faxes are just over the horizon.
A fabber converts a digital computer file into a three-dimensional
object by printing the object one two-dimensional layer at a time. Its
raw material is a liquid polymer that hardens when a laser shines on it.
The laser breaks apart certain molecules in the liquid, converting them
into a kind of glue that binds the spaghetti-like polymer chains
together, thereby solidifying them.
To print, say, a coffee cup, a fabber trains its computer-guided laser
beam onto a vat of the liquid polymer. The laser first scans a solid
circular region on the surface of the liquid, hardening it into a disk--
the base of the cup. Next the base, which rests on a platform in the
vat, is lowered about five-thousandths of an inch, just enough for a
thin film of liquid polymer to wash over it. The laser traces a hollow
circle over this liquid, forming the bottom layer of the cup wall, which
fuses with the base. Layer after layer, the laser traces the cross
section of the cup, building it from the bottom up--including the
handle. By printing one cross section at a time, a fabber can build
objects that are much more complex than a coffee cup.
Since industrial design these days is typically done on computers,
fabbers allow manufacturers to convert their designs into prototypes
quickly. Using a fabber built by 3D Systems of Valencia, California,
engineers at Chrysler recently printed out their design for a new engine
block. The 3-D model revealed a mistake: a misaligned hole that had gone
unnoticed in the complicated blueprint. Correcting the error before the
engine went into production saved Chrysler millions of dollars.
Fabbers are proving invaluable outside manufacturing as well, says
physicist Marshall Burns, who is something of a guru to the burgeoning
young industry. (Burns also heads his own company, Ennex Fabrication
Technologies.) Mathematicians at the University of Massachusetts and a
few other institutions have already latched onto fabbers. "They can now
hold a model in their hands and physically see what their equations
describe," says Burns. "They used to make graphs on a computer screen;
now they have three-dimensional computer graphics."
Linked to the appropriate type of scanner--any device that maps the
shape of an object and stores it in digital form--a fabber becomes a 3-D
copier. The UCLA Medical Center uses a 3D Systems fabber with its CT
scanner. From a CT scan of a patient's fractured skull, surgeons
recently printed out a 3-D model they could use to plan their operation.
Similarly, conservators at the Getty Museum in Malibu, California, have
laser-scanned artifacts and fabbed copies.
From 3-D copier to 3-D fax machine requires no technological leap at
all. "If the scanner and fabricator are far apart, you have a 3-D fax
machine," says Burns. With fabbing, transporting and storing solid
objects becomes as easy as transporting and storing digital data. At the
moment, the objects can be made only of plastic, but various schemes for
fabbing things out of metal are under development.
One customer is the Navy. "The warehouse on an aircraft carrier is about
half the size of a football field, with a 20-foot ceiling," explains
Burns. "Fully half of that stuff is nuts and bolts and cylinders and
flanges, stuff that is simple, but if you're in the middle of the ocean
and you don't have it you're in trouble. The Navy would like to replace
that space with a few fabricators and some bins of steel powder."
Burns predicts that within 15 years, fabbers will be inexpensive enough
to have at home as well as on aircraft carriers. (Right now the typical
one costs around $200,000.) People will dial blueprints on-line, he
thinks, and fab anything from colanders to bookends. Says Burns, "You
won't believe the things you'll see."
AT&T, as sponsor of "Selected Technical Articles," is not responsible
for, nor does it have any connection with the editorial content,
technologies referenced, opinions, theories or any other element of the
article itself.
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