Graphics Reference
In-Depth Information
cookie dough are a popular raw material for food-loving print enthusiasts.
Another emerging printing material is “living ink.” Living ink is a blend of
living cells placed in a special medical gel that medical researchers use for
bioprinting research.
Although manufacturing and design companies use large and expensive
printers of this sort, selective deposition printers are ideal for home, school,
or ofice use. Even low-end printers of this sort operate quietly, and the fact
they use a relatively low-temperature print-head makes them safer to operate
than printers that use high-powered lasers.
A major downside of selective deposition printers is that they can print only
in materials that can be extruded or squeezed through a print head. Molten
metal or glass, for example, must be shaped under different conditions. Most
deposition printers on the market today keep things simple by using a special
type of plastic that's created especially for them. 3D printing plastic is sold in
spooled, spaghetti-shaped strands whose end is fed directly into the printer
where the plastic is melted and squeezed out through the print head.
PolyJet printing
PolyJet printers are the youngest members of the deposition branch of
the printer family, developed in 2000 by an Israeli company called Objet
Geometries (which merged with Stratasys in 2012). PolyJet printers borrow
technologies from both major branches of the 3D printer family tree, combin-
ing a print head that sprays liquid photopolymer into extremely thin layers
and irms up the photopolymer with a bright UV lamp.
The beneit of using PolyJet printing is that spraying droplets is a fast and
precise way to lay down layers as thin as 16 microns. As a point of reference,
the diameter of a red blood cell is about 10 microns. The precision of PolyJet
printers makes them ideal for industrial or medical applications, where “high-
resolution” shapes and fast printing can be mission critical. PolyJet printers
can use several print heads at once so they can print in multiple materials in
a single print job.
A major downside of PolyJet printing lies in inherent limitations in the print-
ing material it uses, a type of plastic called a photopolymer. Photopolymers
are highly specialized, expensive plastics that respond to UV light. Plastic
can be one of the most rugged manufacturing materials there is, but most
photopolymers are still relatively fragile and brittle, which limits their range
of applications.
