However, a small detailed part, like a
dental model for example, is more cost-effective to build with PolyJet. Removing
supports from between the teeth and
creating the cracks and features on
them would be difficult to build with
Stereolithography and would require
extensive hand sanding and finishing.
PolyJet’s water blasted supports are easier
to remove than Stereolithography’s support
structures, thus reducing touch labor.
Additionally, PolyJet’s fine resolution will
have no problem revealing the intricate
features of the teeth. Apart from size, cost
depends on geometry and surface finish.
Photopolymer Materials and
Applications for Stereolithography
PolyJet and Stereolithography materials
are tailored to meet unique applications.
For example, Stereolithography offers a
material specifically tailored to investment
casting patterns, and PolyJet offers multi-material printing in a range of elastomeric
PolyJet is especially unique in the world
of 3D printing because it prints in multiple
materials and colors simultaneously. Multi-
material, or hybrid printing, can produce
a durometer range from 20 to 90. PolyJet
hybrid parts can print opaque stiff parts with
over-molded rubber features in one build;
there’s also a broad combination of color and
durometer. The process has found a special
niche in delivering color print models
without necessitating hand labor to sand
and paint the models. The color models
(Figure 7) are used in consumer prototyping
where color and product touch and feel are
Since its invention, Stereolithography
has been a key player in the creation of
investment casting patterns. Unlike lost wax
patterns, 3D printed investment cast patterns
don’t require tooling, thereby reducing
capital costs for large one-off patterns.
Stereolithography patterns offer two
other benefits apart from design freedom:
Photopolymers developed specifically for
investment casting and a build style that
facilitates ideal burnout. These investment
cast patterns build with a mostly hollow
interior and reinforced outer shell; the
interior is mostly air and creates an overall
much lighter pattern compared to lost wax.
It would be difficult to impossible to copy
this build style using PolyJet or any other 3D
One area in which Stereolithography and
PolyJet complement each other is in the
creation of master patterns for cold mold
Figure 6: Special brushes scrap away residual support material after a PolyJet part has been water-blasted.
Chart 1: Vero White and PolyJet Digital ABS, or GreenFire, are common
PolyJet materials while Somos NeXT and SC4500 or SLA White are common
Stereolithography materials. When it comes to tensile strength and impact
resistance, PolyJet tends to rank higher than Stereolithography. The chart
reflects internal testing by Stratasys Direct Manufacturing during an
overview comparison of our more popular photopolymer materials.
Figure 7: PolyJet can print designs in multiple opacities,
colors and durometers simultaneously.