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What Is the Polyjet Process In 3D Printing?

Polyjet in 3D Printing Colorful

The transformative power of 3D printing is undeniable. The use of 3D printing is rapidly growing in prototyping and design. Hence, it’s no surprise that 3D printing technology is also evolving to meet these demands that increase the usefulness and efficiency of this technology. 

Polyjet Technology is a full-color 3D printing technology that combines the strengths of both plastic and powder-based technologies. Additionally, it delivers the best hybrid of power, speed, quality, reliability, and flexibility in one print. So, if you are looking for that extra edge for your prototype in terms of materials, aesthetics, and accuracy, Polyjet is the way to go. 

Read on to learn everything about this innovative 3D printing technology for your current or future projects. 

 

What is Polyjet? 

Polyjet is a 3D printing technique and a patented invention of Stratasys. It is an additive manufacturing system. However, it works quite differently from other printing technology. 

The Polyjet print head uses liquid photopolymers to create your models. It is similar to a regular inkjet printer. The difference, instead of ink on paper, Polyjet prints layer upon layer of the photopolymers on the build tray. 

Polyjet printers can be as accurate as 0.1mm to create the smoothest surfaces and thinnest walls. Thus, making them ideal for producing prototypes with complex geometries. Furthermore, only Polyjet allows you to mix different materials. In short, you can combine rigid materials with flexible ones in the same print run. 

Polyjet also supports an extensive range of colors and material combinations to produce incredibly realistic prototypes. 

Google Jacquard tag protoypes
Google Jacquard tag prototypes used Stratasys’ multi-color PolyJet 3D printing technology
(image credit: ATAP)

How Does Polyjet 3D Printing Work? 

The Polyjet printing process typically has three main steps: pre-processing, production, and support removal. 

In the first stage, you import your CAD file into the Polyjet 3D printing software. This is where you arrange the order of printing. Whereas, each photopolymer layer is jetted onto the printing plate and cured using a flash of UV light. 

If you need multiple materials in one model or multiple parts printed in a single run, this is where you determine the size, colors, and support structures. 

The production stage is where you hit the “print” button and the Polyjet printer and observe your prototype come to life. Polyjet printing is significantly faster than other 3D printing processes. The reason is, it deposits liquid resins onto the print bed rather than extruding the model from semisolid materials. 

Finally, support removal. Whereby, Polyjet gel-like support structures separate from the model, either by hand or using water. Usually, no other processes are necessary to cure a Polyjet prototype. Once it’s off the 3D printer and clean of support materials, it is ready for testing or uses depending on the development stage. 

Polyjet-printed Heart
Polyjet-printed Heart (source: 3dnatives)

Polyjet Technical Specifications 

When designing your prototype for Polyjet 3D printing, always factor in the capabilities of your printer itself. Even if your CAD model is as accurate as possible, the final product is always subject to changes in shape, textures, colors, and finishes. 

The Polyjet printing process alters the physical model but to a slightly less degree than other 3D printers. The following table of specifications is a good starting point when working with a Polyjet printer. Although it has these specifications, these are definitely not limitations of Polyjet 3D printing. 

Instead, they are the frameworks that allow you to create any prototype.  

Accuracy 0.1-0.3 mm (30 microns) 
Layer resolution16 microns
X/Y resolution 0.0017 in
Wall thickness (minimum) 1 mm
Feature size (minimum) 0.0012 in (0.3mm)
Part dimensions (normal resolution)19.3 x 15.35 x 7.9 in 
Part dimensions (maximum) 39.3 x 31.4 x 19.6 in 
Shore hardness range27 A to 95 A
Finishes Matte, glossy, and custom finishes depend on the type of materials. 

 

Materials Used in Polyjet 3D Printing 

Thousands of material combinations are now available with Polyjet printing that are impossible to achieve in other types of 3D printing. Now, you can combine materials, features, textures, and colors to create stunningly realistic prototypes or models. 

Polyjet offers eight distinct types of materials with unique qualities when used in single material printing or multi-jetting, or hybrid printing.

  1. Digital Materials 

Digital material is a type of combined material in Polyjet 3D printing. Using multi-jetting 3D printers, you can print digital materials which can mix up to six different resins. Additionally, the prototypes can be as detailed and complex as necessary. Therefore, allowing you to be as creative as possible with the outcomes. These flexible or rigid materials can support hundreds of thousands of color options too. 

  2. Digital ABS Plastic 

Digital ABS plastics are stronger and more heat resistant than regular ABS plastic. Prototypes made from this material can have very thin walls but with better dimensional stability. Electrical parts, engine parts, smartphone cases, or any product that needs to snap to fit can be 3D printed using digital ABS plastic. 

  3. Rubber-Like Materials 

Prototype Polyjet
Photo by Tom Claes on Unsplash

Prototypes that need a level of flexibility or soft coatings can be 3D printed using Polyjet rubber-like materials. These prototypes include products that need nonslip surfaces, soft-touch grips and handles, gaskets, seals and hoses, and even footwear prototypes for athletes. Also, you can combine rubber-like materials with rigid materials to produce a range of Shore hardness values, from Shore A 27 to A 95. 

  4. High-Temperature Materials

With high-temperature Polyjet materials, you get excellent dimensional stability in prototypes and models exposed to heat. You can combine high-temperature materials with rubber-like materials to improve the hardness and flexibility of their insulation. Polyjet high-temperature materials are excellent for functional prototypes that have to withstand a lot of heat or function in strong lighting conditions. 

  5Transparent Materials 

Polyjet transparent materials are great for prototypes that need see-through parts. You can also add colors to the transparent materials to get an impressive range of tints for your model. 

These materials are ideal for prototyping glass products, eyewear and product cases or covers, and other numerous medical applications like contact lenses and clear dental aligners. 

  6. Rigid Opaque Materials 

If you’re looking for the broadest possible range of color options for your prototype, Polyjet rigid opaque materials are worth exploring. When combined with rubber-like materials, they create moving or assembled parts and electronic components. Additionally, they result to products that must feel soft to the touch and appear vibrant for easy identification. 

  7. Simulated Polypropylene Materials 

Simulated Polypropylene materials simulate the qualities and appearance of polypropylene. For example, this typically exist in things like product packaging, laboratory equipment, car components, living hinges, sound speakers, and plenty of other applications. If you’re looking to test or exhibit a polypropylene prototype, make it using 3D simulated polypropylene first before going into full production. 

  8. Biocompatible Materials 

Polyjet biocompatible materials meet the approval required for medical use on five key factors. This factors includes: genotoxicity, cytotoxicity, delayed hypersensitivity, irritation, and USP plastic Class VI. Using these materials, you can create colorless prototypes that need short-term exposure to mucosa membranes for up to 24 hours. In addition, you can also produce prototypes that will be in contact with the skin for more than 30 days.

Architecture Polyjet
Photo by Jonathan Borba on Unsplash

Polyjet 3D printers

A wide range of Polyjet 3D printers is available today, from small, compact sizes to large-scale industrial printers. Here are few examples:

Objet30 V5 Pro & Prime | Stratasys™
Objet30 V5 | Credit: Stratasys

 

Objet30 V5 series

The Objet30 V5 series is the smallest, and they come in the Pro and Prime versions. These printers print single materials plus support materials, as does the slightly larger J55 model. 

Connex1 Objet260 & Objet500 | Stratasys
Objet500 Connex1 | Credit: Stratasys

 

Objet Connex1 series

Other single material printers include the Objet Connex1 series that come in the 260 and 500 models. You can print digital materials using the Objet Connex3 series printers (260, 350, and 500 models).

J8 Series | Stratasys™
J8 Series | Credit: Stratasys

 

J8 series

This series, offers an unlimited number of composite materials and over 500,000 color options. The largest Polyjet printer is the J4100, which allows a maximum model weight of 135kg on the printing plate. 

The most highly specialized printer in this series has to be the J750 Digital Anatomy printer which can produce super realistic bone and tissue models. It also uses a gel-like support material that is easy to remove from blood vessel models without altering the delicate prints. 

How to Choose

The biggest factor in choosing a Polyjet printer is the materials you want in your prototypes. A compact Polyjet 3D printer is more affordable when using single materials. Moreover, it delivers the best resolution and surface finishes for its size. 

If your model requires multiple materials, larger stand-alone Polyjet printers are ideal. This is because they feature multi-jetting technology. There are three main ways to use this hybrid 3D printing feature;

  • You can mix several materials into one model or one part of a model, 
  • Blend separate materials to create a brand new one, or 
  • Use mixed trays such that one print run can produce multiple individual parts printed using different materials.

Ultimately, it is your end goal that determines your choice of a Polyjet printer. Are you looking for a delicate, flexible prototype for a surgical implant? Or a series of complex moving parts for a robot? Or an entire fashion brand featuring 3D designs? Polyjet 3D printing can precisely produce what you need faster than other 3D printing options.

Polyjet Thorasic Cavity
Photo by Nino Liverani on Unsplash

Advantages of Polyjet 3D printing 

Polyjet 3D printing has four significant advantages for product designers, engineers, medical professionals, and artists in their creative and manufacturing processes.

   1. Save At Least 50% Of Your Time

We have highlighted that Polyjet printing is fast, and the prototype is ready to use as soon as it’s off the printer. Hybrid printing also means that you can print several objects on one print run or combine several materials into one prototype. 

This translates into more time to design, test, and perfect the prototype. Therefore, leads to a quicker route to full-scale manufacturing and marketing. 

  2. Realistic Models for Medical Applications 

Anatomical models used for teaching and planning surgeries must be as close to real-life as possible. The material combinations offered by the Polyjet system can make 3D printed models. These models will not only look realistic but also feel and respond just like the human body. 

As a result, this improves the health outcomes of patients because their doctors are better trained. On top of that, their implants and prosthetics are thoroughly tested and simulated beforehand. 

  3. High Accuracy

The more accurate and detailed a product’s design is 3D printed, the more precise its final prototype will be. Whether you want a perfectly smooth, polished product or complex, intricate details down to the microscopic level, the Polyjet process precisely produces what you need. 

  4. Multi-Material Capability 

Digital materials, which result from mixing multiple types of resins, offer designers and engineers unprecedented creative opportunities. As a result, you can build robust prototypes without losing out on flexibility, textures, or colors. No other 3D printing technology can do this apart from Polyjet. 

Now that we have seen what the Polyjet process is all about, it is worth comparing it against two other types of 3D printing, SLA and FDM

Differences Between Polyjet and SLA  

Stereolithography (SLA) is the oldest technology in the 3D printing industry. The only similarity between SLA and Polyjet is that both use a liquid resin that turns solid when exposed to UV light. The main difference is in the printing process itself. Whereas, SLA printers extrude the object out of a pool of resin, producing the object upside down. In contrast, Polyjet printers jet the resin onto the build plate, eliminating exposure to hazardous resins and building the object from the bottom up.

Moreover, SLA printers work with a single material per print run. On the other hand, Polyjet allows multiple materials and multiple objects per print run. 

SLA models also print breakaway support materials, which require sandblasting or washing in an alcohol bath during post-curing. However, the gel-like support materials produced in the Polyjet process are removable by hand or water, saving time on post-curing. 

Differences Between Polyjet and FDM 

Both fused deposition modeling (FDM) and Polyjet printers build models layer by layer. However, FDM printers deposit heated thermoplastic filaments on the printer bed that cool and solidify to create these layers. In contrast, Polyjet printers use liquid photopolymers cured using UV light. 

FDM also uses a limited number of materials, mainly ABS, ASA, PC-ABS, and polycarbonate. On the contrary,  Polyjet uses unique digital materials for a broader range of applications. 

FDM materials are in a semisolid state during 3D printing. However, the finished models are generally sturdier and more durable but are limited in their flexibility and detail. Differently, Polyjet printing delivers more details because the resins are in a liquid state. 

Factors to Consider When Using Polyjet 3D Technology 

Polyjet technology applies to many products. This includes prosthetics, implants, mobility aids for healthcare, architectural models, robotics prototypes, interlocking structures and tools in the industrial manufacturing sector, and bespoke designs for cars, bikes, and airplanes parts. 

With all these options on the table, it’s essential to understand which materials and processes are best for each product type. So far, we have discussed the features and advantages of Polyjet printing, so let’s consider the four main questions to determine if Polyjet printing is suitable for you. 

How Will Your 3D Model Be Used? 

Before printing your 3D model, keep in mind the end use or purpose of the product. Polyjet technology is best known for the level of flexibility and intricate details it offers. Therefore, it lends itself to medical applications and geometric designs for mechanical parts. 

Nevertheless, if aesthetics is a key factor, for example, in creating product packages, footwear, eyewear, or artistic exhibitions, Polyjet is the best option. If you need a combination of robustness and aesthetics, you can strike this balance with the Polyjet process. 

Which Material Is Best? 

Before Polyjet technology, early 3D printers relied on a single material, usually plastics. The reason is, it produced rigid, sturdy products with a limited range of color options. 

Now, Polyjet frees you to explore textures, colors, and flexibility. As a result, it will enable your end product to meet and exceed end-user expectations. Do consider the cost of producing digital materials because single materials are generally more affordable than hybrid materials. 

Which Is the Best Type of Surface Finish? 

Tools and components for mechanical or industrial applications require a different type of finish from medical parts or packaging products. For pieces that snap to fit, a smooth finish is excellent. At the same time, a nonslip finish is best for handheld products, mobility aids, and footwear. 

  • What Is the Size of The Prototype? 

Polyjet allows a maximum part size of 19.3 x 15.35 x 7.9 inches in a single print run. Consequently, for any parts larger than this, you can design separately and then fit together seamlessly after printing. Factor in the support materials in the CAD design to understand how to work within the dimensions of Polyjet printers. 

Conclusion 

Polyjet 3D printing combines liquid digital materials and dissolvable support materials with faster printing speeds to produce quality prototypes. This technology gives the finest resolution of all 3D printing technologies. Therefore, you can integrate smaller, more detailed patterns into each design. Additionally, one Polyjet prototype can feature different Shore hardness ranges, multiple materials, and a gamut of brilliant colors. 

Ready to bring your CAD design into life? Get in touch with Jiga for a quick, comprehensive quote. We also give you access to Polyjet 3D printing professionals that will get your prototype ready in no time. Contact Jiga today. 

Adar Hay
Adar Hay
Co-Founder and CEO of Jiga. Adar is a tech industry revenue leader with vast experience in product and marketing management. He's driving Jiga's mission to make parts sourcing frictionless.

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