Material Jetting 3D Printing Process Explained

Material Jetting is an advanced form of 3D printing that excels in creating detailed and complex parts. By jetting fine droplets of photopolymer and immediately curing them with UV light, this technology achieves a level of precision akin to digital inkjet printing. This article explores the key concepts, applications, and intricacies of Material Jetting, offering insights into why industries value its precision and versatility despite considerations of cost and part durability.

Key Takeaways

  • Material Jetting (MJ) is an advanced 3D printing process that allows for high precision and multi-material printing. It uses UV light to cure liquid resin layer by layer.
  • Various techniques within Material Jetting, such as PolyJet, NPJ, and DOD, cater to different applications, and while MJ offers a smooth surface finish and intricately detailed parts, it comes with higher costs and potential brittleness in finished products.
  • Material Jetting’s application spans numerous industries, including automotive, aerospace, medical, and design, emphasising its versatility. However, the process requires significant post-processing, including support removal, surface finishing, and UV curing for part quality.

Understanding Material Jetting: The Basics

Material Jetting, born out of the innovative 90s, captures attention with its exceptional precision and flexibility. Born from the innovative minds of companies like Solidscape and 3D Systems and later patented as PolyJet by Objet Ltd., material jetting 3D printing has made its mark as a game-changer in the realm of 3D printing. So, how does it work exactly? Material jetting printers, like sophisticated inkjet printers, use heated liquid resin instead of ink, which they jet onto a build platform. The droplets land precisely where they should, layer upon layer, and are immediately cured by UV light, transforming the liquid resin into a solid object of your design.

The distinctive characteristic of Material Jetting lies in its capability to fabricate objects at the voxel level, akin to pixels in a 2D image but with an added dimension of depth. This offers unprecedented control over the structure and properties of the printed object. What’s more, Material Jetting can mix different materials within a single print, enabling the creation of objects with varied properties like hard and soft or opaque and transparent in different areas of the print. This multi-material capability opens up a world of possibilities for designers and manufacturers alike.

Material Jetting vs. Traditional 3D Printing

Like all technologies, Material Jetting has strengths and drawbacks. Compared to traditional 3D printing techniques, Material Jetting stands out for its speed and multi-material capabilities. By depositing material line by line and instantly curing it with UV light, Material Jetting significantly enhances the printing speed. This gives it an edge in applications where quick turnaround times are essential.

However, this speed and versatility don’t come cheap. The cost of systems designed for Material Jetting is typically higher than other types of 3D printing systems. This is due to the complexity and proprietary nature of its printhead technology, which requires significant investment in research and development.

Yet, for industries where precision, detail, and customisation are paramount, the benefits of Material Jetting often outweigh the costs.

Key Components of Material Jetting Systems

The essence of Material Jetting resides in its key components:

  • UV light sources: These are crucial as they are used to cure the photopolymer layers during the printing process. The light source is usually housed in the moving printhead, enabling immediate curing after the material is jetted.
  • Print heads are responsible for jetting the material onto the build platform.
  • Build platforms: These provide a stable surface for the printing process.

The print heads are the heart of any material jetting system. They are responsible for dispensing material in precise droplets to form each layer of the object being printed. The build platform, on the other hand, provides the foundation for the layered construction of parts, supporting the object as it takes shape. Each of these components plays a vital role in the Material Jetting process, contributing to the accuracy and quality of the printed parts.

Material Jetting Techniques: PolyJet, NPJ, and DOD

PolyJet technology

As with any technology, material jetting technologies are not a one-size-fits-all solution. They encompass several techniques, each with unique capabilities and applications. PolyJet, NanoParticle Jetting (NPJ), and Drop-On-Demand (DOD) are the three main types of Material Jetting techniques.

We will explore each of these techniques, understanding their unique characteristics and their contribution to Material Jetting’s adaptability.

PolyJet Technology

PolyJet technology is a star player in the Material Jetting lineup. It stands out for its ability to produce parts with diverse properties, including:

  • rigid
  • opaque
  • transparent
  • rubber-like with varying hardness levels

This versatility is a boon for industries that require varied part characteristics.

An additional benefit of PolyJet parts is their limited need for post-processing beyond the removal and cleaning of support structures. This reduces the time and resources needed for finishing, thus speeding up the production process. The diverse material properties achievable with PolyJet technology enable its application across different industries, including:

  • Aerospace
  • Automotive
  • Consumer goods
  • Education

NanoParticle Jetting (NPJ)

NanoParticle Jetting (NPJ) is an advanced 3D printing technology that utilises tiny nanoparticles to build up the desired object. The use of nanoscale metal particles allows NPJ to produce parts with a high resolution, with layers so fine they are nearly invisible to the naked eye.

This high-resolution capability makes NPJ a perfect fit for industries like automotive that require intricate components. After printing, NPJ parts undergo thermal curing to increase their strength before they are extracted and sintered, enhancing their durability. This makes NPJ a valuable tool in the production of detailed prototypes and functional parts.

Drop-On-Demand (DOD)

Drop-on-demand (DOD) is a material jetting technique that precisely controls the deposition of material. It works by ejecting droplets through a nozzle only when needed, a process achieved by either thermal or piezoelectric actuators.

The advantages of DOD printing include:

  • The ability to adjust the droplet size, which is crucial for achieving the desired resolution in printed parts
  • The ability to handle a variety of materials, including photopolymer, which hardens upon UV exposure, and even viscous materials, providing flexibility in the choice of materials used for different applications
  • Precise material deposition, allowing for the creation of high-quality and complex structures

It is commonly used for creating high-resolution prototypes and small-batch production parts.

Materials Used in Material Jetting

Composite materials in Material Jetting

The choice of materials used in Material Jetting is as diverse as its applications. Material Jetting can handle a variety of materials, including:

  • Thermoset photopolymer resins that solidify when exposed to ultraviolet light
  • Ceramic materials
  • Metallic inks for electronic circuits
  • Dissolvable support materials are essential for creating complex geometries without compromising structural integrity during the build process.

However, the materials suitable for Material Jetting are limited to those that can be deposited in droplet form, including a range of polymers and waxes.

Base Resins

Base resins play a crucial role in Material Jetting. These resins are characterised by specific properties that distinguish them and can be used directly without any combination. This gives designers and manufacturers the flexibility to select resins based on the desired properties for specific applications.

Whether it’s a resin that offers high strength, flexibility, or transparency, the choice of base resin can significantly influence the performance and aesthetic of the final printed part. This makes the selection of base resins an important step in the Material Jetting process.

Composite Materials

Composite material technology brings another dimension to the capabilities of Material Jetting. Allowing base resins to be mixed in specific ratios enables the creation of digital material with tailored physical properties like hardness and colour.

This ability to process hard and soft polymeric materials simultaneously allows designers to craft parts with distinct sections of varying stiffness, contributing to the design of complex parts. From mimicking the mechanical properties of natural composites to achieving the desired aesthetic qualities in a finished part, composite materials offer endless possibilities in Material Jetting.

Dissolvable Support Structures

Not to be overlooked, dissolvable material in the form of support material holds a key role in Material Jetting. These materials allow the creation of complex structures while ensuring smooth surfaces post-removal.

Support materials are specifically printed to be easily removed from the final print using water jets or ultrasonic baths, making post-processing simpler. The use of dissolvable supports gives designers more freedom in orienting parts during the design phase without worrying about the complexities of support removal.

However, while support structures are necessary for intricate designs, they do add to the production costs of Material Jetting operations.

Advantages and Limitations of Material Jetting

Although Material Jetting is a potent tool in the realm of additive manufacturing, comprehending its advantages and limitations is crucial. Recognised for its high level of accuracy, multi-material flexibility, and ability to create complex geometries, it has earned its place in industries where precision and detail matter.

However, it also faces challenges in terms of cost, durability, and production speed, which can limit its suitability for certain applications.

Benefits of Material Jetting

Material Jetting presents a multitude of advantages, establishing it as a favoured choice for a myriad of applications. Some of its advantages include:

  • Creating objects with a precision similar to that of two-dimensional inkjet printers, ensuring high accuracy in the final product
  • Excellent surface finish, adding to the aesthetic and functional quality of the printed parts
  • Suitable for industries that value high-quality finishes

Moreover, Material Jetting allows for the creation of parts with varied material properties within different areas by jetting multiple materials concurrently. This multi-material capability opens up a world of possibilities for designers and manufacturers alike, enabling the creation of prototypes and end-use parts that require excellent accuracy and complex geometries. With its versatility, Material Jetting is highly suitable for industries ranging from aerospace to consumer goods.

Challenges and Limitations

Despite the numerous benefits Material Jetting provides, it also brings along its own set of challenges. One of the potential drawbacks of Material Jetting technology is the higher cost compared to other forms of 3D printing due to the specialised equipment and materials required.

Another limitation is the durability of the parts produced. Material Jetting parts can be brittle, restricting their application for functional components. Additionally, it involves a slow production speed due to fine layer printing and becomes less efficient as part size increases, representing a challenge in scaling up the size of parts.

Despite these challenges, the unique capabilities of Material Jetting make it a valuable tool in the arsenal of additive manufacturing technologies.

Applications and Industries Utilising Material Jetting

The use of Material Jetting is not confined to one specific industry or application. Its versatility and accuracy have made it a popular choice across a broad spectrum of industries, including:

  • Automotive
  • Aerospace
  • Consumer goods
  • Medical

Material Jetting has showcased its wide appeal and applicability.

Automotive Industry

In the automotive industry, Material Jetting is instrumental in creating reliable prototypes, facilitating a more efficient and iterative development process. The benefits of Material Jetting in the automotive industry include:

  • Enhanced accuracy in prototype production
  • Rapid production capabilities
  • Detailed analysis and refinement of automotive components during the testing phase

These advantages contribute to a more streamlined and effective development process in the automotive industry.

By accelerating the prototyping and testing phases, Material Jetting plays a key role in shortening the time required to introduce new automotive products to the market. The automotive sector benefits from Material Jetting’s rapid prototyping, which results in faster product development cycles and a quicker transition from design to production.

Medical Industry

In the medical industry, Material Jetting holds a special place. Its ability to deliver personalised medical solutions is significant, aligning with the fundamental need for customisation in patient care.

Medical professionals utilise Material Jetting for various applications in the medical industry, including:

  • Creating highly detailed full-color prototypes
  • Producing medical models for planning complex surgical procedures
  • Manufacturing tools, instruments, and functional parts of medical devices

Material Jetting is known for its high precision and is widely used in the medical industry.

Anatomical models produced via Material Jetting play a vital role in preoperative planning, medical training, and educating patients, aiding in the delivery of comprehensive healthcare services.

Art and Design

Art studios and design firms extensively use Material Jetting for the following reasons:

  • It can produce high-resolution 3D prints
  • It can incorporate multiple materials
  • It can produce a range of colours
  • It can create a smooth surface finish

These characteristics are crucial for creating fine art pieces and detailed designs.

Post-Processing and Finishing Techniques for Material Jetted Parts

Post-processing for Material Jetted parts

The post-processing of the printed parts holds equal importance as the printing process itself. In Material Jetting, post-processing steps are crucial for achieving the final part quality and involve support removal, surface finishing, and UV curing.

Support Removal

The first step in post-processing is support removal. Support structures used in Material Jetting are dissolvable, allowing easy removal through agitation.

After the supports are removed, the parts are cleaned to remove any residual material, ensuring the purity and quality of the final product.

Surface Finishing

Surface finishing is another important aspect of post-processing. Depending on the initial printing settings, the overall surface quality and the extent of post-processing required can vary. For instance, choosing a matte printing option results in a surface that is accurately and uniformly finished but may necessitate further cleaning.

On the other hand, utilising glossy printing settings produces a smooth and polished surface finish, minimising the need for post-processing surface work.

Curing and Strengthening

The final step in post-processing is curing and strengthening. Material jetted parts are often cured with UV light immediately after printing, which is essential for converting the photopolymer resin into a solid state.

Multiple curing cycles using UV light can help in achieving better mechanical properties and higher stability in the final parts. Additional post-curing methods, such as thermal post-curing and chemical treatments, can further improve the material properties and stability of the printed parts.

Summary

To sum up, Material Jetting is a versatile and accurate 3D printing technology that has found its way into various industries, from automotive and medical to art and design. Its ability to create complex geometries, combined with its high accuracy and multi-material capabilities, makes it a valuable tool in the world of additive manufacturing. While it does face challenges in terms of cost and durability, the benefits and potential applications of Material Jetting make it a technology worth exploring.

Frequently Asked Questions

What is Material Jetting?

Material Jetting is a 3D printing technology that creates objects by jetting droplets of heated liquid resin onto a build platform in a layer-wise fashion, curing them with UV light. It is used to create high-resolution parts with fine details and smooth surface finishes.

How does Material Jetting differ from traditional 3D printing?

Material Jetting differs from traditional 3D printing by offering faster printing, multi-material capabilities, and complex printhead technology, which results in higher costs.

What are the main techniques for material jetting?

The main techniques used in material jetting are polyjet, nanoparticle jetting (NPJ), and drop-on-demand (DOD). These techniques offer different capabilities for creating 3D-printed objects.

What materials are used in Material Jetting?

Material Jetting uses thermoset photopolymer resins, ceramic materials, metallic inks, and dissolvable support materials for 3D printing. These materials allow for high accuracy and intricate designs.

What are some applications and industries that use Material Jetting?

Material Jetting is widely used in industries such as automotive, medical, and art and design. These industries benefit from the precision and versatility of Material Jetting technology.

14th April 2024

3D Printing