Rapid Prototyping, 3D Printing

PolyJet 3D Printing: A Great Alternative To Old Silicone Molding Techniques

By Heather Sutton on August 6, 2014

PolyJet is one of two methods used to build prototypes onStratasys 3D printers . The process isn’t as complicated as it seems. 3D printers interface with virtual drawings from computer aided design software (i.e. SOLIDWORKS 3D CAD). Using the CAD data, 3D models are built with layers of liquid, powder or sheet material.

Silicone mold with PolyJet 3D printed pattern

PolyJet 3D printing is similar to inkjet printing, but instead of jetting drops of ink onto paper, the printer lays down layers of curable liquid photopolymer onto a build tray. The printer instantly UV-cures these tiny droplets of liquid photopolymer. Fine layers accumulate on the build tray to create a precise 3D prototype.

This process takes only a few hours. After the prototype is finished, any support material that was used can be removed. It should fall away easily with a gentle wash with water. The model is then ready to use with no post-curing needed.

Who is PolyJet best for?

PolyJet is perfect for business that require extremely realistic prototypes or models designed for end use. PolyJet printers create prototypes with smooth surfaces and intricate details. This method is more precise than FDM with the ability to build more complex models. It features 16-micron layers with accuracy as high as 0.1 mm. The smooth surfaces and crisp details make PolyJet patterns mold-ready.

Smooth surfaces and crisp details make PolyJet patterns mold-ready
PolyJet is incredibly versatile. You can also incorporate color into the model or blend two or more materials together with some 3D printers (i.e rubber/rigid and transparent/opaque). In fact, Objet 3D Printers are the only additive manufacturing systems in the world that allow multi-material flexibility, enabling a wealth of applications such as over-molding, grayscale coloring and simultaneous prints in different materials.

How does PolyJet and silicone molding work hand-in-hand?

Silicone molding — also known as room temperature vulcanizing (RTV) molding — creates finished products for prototyping, functional testing and short-run production. Silicone molds are made by pouring silicone rubber over a pattern. Silicone molding is faster, less time intensive and more cost-effective than machining or injection molding.

After curing, the resulting mold can produce parts with extremely complex geometry, intricate detail and tight tolerances. The parts are cast from a silicone mold made with thermoset materials (commonly urethanes) that are available with a vast array of mechanical, thermal and electrical properties.

A silicone mold pattern and mold box are ready for pouringPolyJet is a great replacement for these old methods with a cost savings of anywhere from 30 to 85 percent. PolyJet patterns have smooth, nearly mold-ready surfaces. They have subtle details that can be transferred to the urethane castings. For high-gloss or clear finishes, a little polishing is all that is needed. As if that’s not benefit enough, silicone mold can be ready to make parts in as little as 24 hours using PolyJet.
Want to learn about PolyJet materials? Download our white paper, PolyJet Materials: A Range of Possibilities. 

Download the White Paper