In 2000, Israel’s Objet applied for a patent for PolyJet polymer jetting technology, which Stratasys acquired in 2011. The molding principle of PolyJet technology is similar to that of 3DP, but resin materials are sprayed instead of adhesives. While not as widely used as SLS or SLA, it still plays an important role in the 3D printing process segment. It is an effective production tool for producing smooth-surfaced, dimensionally accurate parts, prototypes, and tooling. The technology provides microscopic layer resolution and accuracy down to 0.1 mm, enabling the creation of thin walls and complex geometries using various materials suitable for any technology. Applications include printing good prototypes with smooth surfaces for final product aesthetics.
Create precise molds, dies, jigs, and other manufacturing tools.
Handles complex shapes and details for advanced features.
Multi-color and material types can be applied to a single model for increased efficiency.
PolyJet can be considered a close cousin of fused deposition technology. Like FDM, it works by printing the part one layer at a time using the extruder head. However, instead of using filaments to deposit material on a print bed, PolyJet works more like 2D inkjet printing, where an extruder deposits tiny droplets of a photopolymer material of choice on the print bed, which are then cured with UV light.
Polyjet 3D printing provides a naturally smooth surface quality, so additional sanding or polishing can be greatly reduced during post-processing. On the other hand, polymer parts can be stained and painted just like SLS parts, which offers many options when creating unique finishes. Polyjet parts can also be glued when needed, allowing you to print larger parts as separate components and then attach them.
How does it work?
The anatomy and printing process of PolyJet 3D printers are the same as material jet 3D printers. Since we already have a detailed article on material jetting (MJ) 3D printing, we won’t discuss the basics here.
As you can see from the image above, the PolyJet printer consists of a material container, a build platform (and its lift), and a carriage that houses the UV lamps and inkjet printheads.
Before printing begins, the photopolymer resin must be poured into the material container and heated. This allows the substance to achieve the desired viscosity.
The printing process begins with the carriage moving along the X-axis on the build platform. As it moves, the printhead selectively ejects resin in droplets onto the build platform. Immediately after spraying them, the UV light solidifies them into a growing solid.
Since there are multiple print heads, different materials can be printed at once. An example application of this feature is a part that needs to be supported, where the support material is built up simultaneously as the main material.
Once a single layer is complete, the build platform will move down one layer in height, and the process will continue until the part is complete.
PolyJet 3D printers work with many different materials, including even bio-resins.
What makes it different?
The two giants leading the development of MJ 3D printing are Stratasys and 3D Systems. The main differences between their devices are the material used for the support structure.
PolyJet from Stratasys uses a dissolvable support material, typically made from polyethylene, propylene, and glycerin.
After printing, the parts fabricated on the PolyJet machine are removed from the build platform and exposed to pressurized water. This removes as much support material as possible without dissolving it. After that, the part emerges in a chemical solution where the rest of the carrier dissolves, leaving a clean part.
On the other hand, the MultiJet 3D printer uses paraffin as a support material. After printing the part on the MultiJet 3D printer, the supports need to be melted in an oven.
The poly jet technology typically uses resin rather than the plastics used in other 3D printing methods. The most basic printers can only use one resin at a time. Still, more sophisticated printers can combine multiple resins during the printing process, providing a lot of flexibility in creating the unique look of a part and even providing different areas of the same part with Independent material quality.
Polyjet resins come in various colors and properties, and stiffnesses range from flexible and rubbery (26-28 Shore D) materials such as Objet TangoPlus to more rigid materials (83-86 Shore D) such as Objet VeroClear. Additionally, overmolded materials are available to add a layer of rubber-like material to tougher parts. Visuals can range from opaque to clear, as well as pure black or white, and are also available in composites of different resins to provide specific material qualities. PolyJet 3D printers give you a variety of materials to choose from and even allow you to combine multiple materials in one 3D printed model. You can use 3D printing to achieve things you never thought possible, such as simulating overmolding, making flexible, colorful prototypes and ergonomic molds, or printing different parts simultaneously. PolyJet 3D printers give you a variety of materials to choose from and even allow you to combine multiple materials in one 3D printed model. You can use 3D printing to achieve things you never thought possible, such as simulating overmolding, making flexible, colorful prototypes and ergonomic molds, or printing different parts simultaneously.
Digital Materials can combine two or three base resins to create nearly 1,000 composite materials with specific, predictable material properties, expanding the possibilities for related applications. A wide range of shades, translucency, Shore A hardness values , and other properties can provide an excellent true-to-life product for innovative prototypes.
Where is it used?
The potential of PolyJet has been recognized by many industries implementing the technology to enhance their workflows and save money.
Because PolyJet is a technology that can produce highly complex parts in hours, it’s especially ideal for making realistic prototypes. When prototyping, time is real money, so it’s best not to waste it.
Another advantage of PolyJet is the ability to 3D print with different materials simultaneously. This enables complex geometry and again saves time (and money).
In addition to prototypes, PolyJet 3D printers can often be found in the dental industry. Modern Clinic utilizes PolyJet to create 3D-printed oral models based on previously performed scans. PolyJet makes this process faster and more accurate than ever.