ing the material. They repeat the process
to build up a three-dimensional object
out of the fused powders. The technique
is impressive in its capabilities, but it’s
slow and expensive. It is worthwhile only
for extremely high-value parts that are
too complex to make using other methods. Notably, GE’s new jet engine uses a
series of sophisticated 3-D-printed fuel
nozzles; they are lighter and far more
durable because intricate cooling channels have been built into them.
The founders of Desktop Metal
decided that to make 3-D metal printing
more widely accessible, they would need
to sell two di;erent types of machines: a
relatively inexpensive “desktop” model
suitable for designers and engineers fabricating prototypes, and one that is fast
and large enough for manufacturers.
Luckily, several innovations have finally
made Sachs’s original invention practical for mass production, including the
development of very high-speed ink-jet
printing for depositing the binder. Successively printing about 1,500 layers, each
50 micrometers thick and deposited in a
few seconds, the production-scale printer
can build up a 500-cubic-inch part in
an hour. That’s about 100 times faster
than a laser-based 3-D printer can make
For its prototyping machine, Desktop
Metal adopted a method from plastic-based 3-D printing. But instead of a
softened polymer, it uses metal powders
mixed with a flowable polymer binder.
The formulation is extruded, using the
printed binder to clump the metal powder
into the intended shapes.
However, whether the part is printed
with the prototyping machine or the production model, the resulting object—part
plastic binder and part metal—lacks the
strength of a metal one. So it goes into a
specially designed microwave oven for sintering, a process of using heat to make the
material more dense, producing a part with
the desired properties. In a series of carefully calibrated steps during the sintering
process, the polymer is burned off, and
then the metal is fused together at a temperature well below its melting point.
The sales pitch
According to the promises of its enthusiasts, 3-D printing will reduce the need for
industrial manufacturers and empower
local artisan producers (see “The Di;erence Between Makers and Manufacturers,”
KEY PLAYERS IN 3;D PRINTING
Stratasys One of the original 3-D-printing companies, Stratasys was
founded by Scott Crumb, the inventor of fused deposition
modeling, the most common way to print plastic parts.
Sells machines that can print a variety
of photopolymer and thermoplastic
Carbon This Silicon Valley startup has developed a novel photochemical
process for fabricating parts out of various plastics, including
polyurethane and epoxy.
Introduced a modular system for
manufacturers this spring.
HP Its line of machines exploits the company’s long history
with ink-jet printing through what it calls “multi jet fusion
technology.” This uses multiple nozzles for high-speed and
Introduced its first 3-D printers last
year. The initial machines print nylon,
but the company is looking to expand
to other materials.
3D Systems The first 3-D-printing company, 3D Systems was founded by
Chuck Hull, the inventor of stereolithography, which uses light to
form parts out of photopolymers. It now o;ers various types of
3-D printers, including some that print metal parts.
Introduced the latest iteration of
stereolithography last year.
COMPANY TECHNOLOGY PRODUCTS