The Ins and Outs of Multi Jet Fusion MJF 3D Printing Technology

Multi Jet Fusion, commonly abbreviated as MJF, is an innovative powder bed fusion 3D printing process that uses jetting technology to selectively deposit fusing and detailing agents onto a powder bed to create each layer of a part. MJF delivers excellent mechanical properties, high accuracy, and productivity advantages compared to other additive manufacturing technologies.

This article provides an in-depth look at how MJF 3D printing works, its key benefits, applications, materials, and service providers that offer MJF printing services. Read on to learn everything you need to know about this game-changing industrial 3D printing technology.

What is Multi Jet Fusion MJF 3D Printing?

Multi Jet Fusion is a powder bed fusion 3D printing process developed and commercialized by HP in 2016. It works by selectively depositing fusing and detailing agents from inkjet printheads onto a powder bed to fuse areas of powder material together layer-by-layer.

MJF printing utilizes two key agents:

• Fusing Agent: This agent is deposited on areas that will become solid parts in that layer. It absorbs infrared radiation and helps fuse powder particles together during the fusing step.
• Detailing Agent: This agent is selectively applied around part contours on each layer. It prevents fine powders from sintering in high-detail areas to achieve sharper edges and finer feature resolution.

After each layer is printed, the entire build platform moves down by one layer thickness and a roller spreads a fresh layer of powder over the build platform. The powder bed is then preheated using infrared lamps to partially fuse the powder. Next, the printheads deposit fusing and detailing agents as required. An infrared lamp then fully fuses areas that received fusing agent to bond particles together into a solid part layer.

This process repeats layer-by-layer until the full 3D object is complete inside the powder bed. The unfused powder surrounding the printed parts acts as support during the build. Once printing is finished, the operator removes the build container and recycles unused powder. The parts are then cleaned to remove any remaining powder before post-processing if required.

Key Benefits of Multi Jet Fusion 3D Printing Technology

MJF offers several benefits that make it appealing for production applications:

• High Throughput: MJF printers can achieve extremely fast build speeds. HP’s MJF 5200 printer can print up to 80 mm per hour vertically, while the larger MJF 5400 can print up to 122 mm per hour. This makes MJF ideal for mass production of end-use parts.
• Excellent Mechanical Properties: Parts printed with MJF exhibit isotropic properties and have similar strength to injection molded parts. For example, HP 3D High Reusability PA 12 material has 50 MPa tensile strength.
• High Accuracy and Resolution: MJF printing can achieve accuracy as high as ±0.08 to 0.30mm per 25.4mm at 3σ. Minimum feature size is around 0.1mm, providing high part resolution.
• Low Porosity: MJF printed parts have low porosity of around 1-3%, providing water-tight parts suitable for functional applications.
• Low Residual Powder: MJF does not require supports, allowing for easy powder removal. Parts have a smooth ‘sandblasted’ finish.
• Minimal Post-Processing: MJF parts require no solvents or additional curing. Support removal and surface finishing may be required depending on application.
• High Reusability of Material: Around 80% of unfused powder can be recycled for future builds, reducing waste.
• Batch Printing: MJF build volumes allow printing of multiple parts in one build, increasing productivity.
• Variety of Materials: MJF printers can utilize production-grade thermoplastics like PA11, PA12, TPU, TPE, and more.

With these advantages, MJF is ideal technology for short-run production applications across aerospace, automotive, industrial machinery, and consumer product industries.

MJF 3D Printing Materials

A range of thermoplastic materials are available for Multi Jet Fusion print systems, providing options for both prototyping and end-use parts production. Here are some of the most common MJF materials:

• PA11 and PA12: Nylon materials like PA11 and PA12 offer excellent strength, thermal resistance, and durability. They are commonly used for functional prototypes and end-use parts.
• TPU and TPE: Thermoplastic polyurethane and elastomers provide flexible and elastic properties. They are suitable for applications like seals, gaskets, and snap fits.
• PEEK: Polyether ether ketone offers very high heat resistance up to 310°C and is an excellent alternative to metals. It is often used in aerospace, automotive, and energy industries.
• ULTEM: These PEI filaments offer high flame retardancy, temperature resistance, low smoke emission and are FST certified for aerospace use.
• Composites: Reinforced thermoplastics like PA12 with glass beads, aluminum, or carbon fibers enable high strength and stiffness while retaining thermal and chemical resistance.

HP also offers its Multi Jet Fusion 3D Printing Solution for developing custom materials tuned for specific applications. Many service providers offer a wide range of both standard and custom MJF material options.

MJF Applications and Suitable Industries

The key advantages of Multi Jet Fusion 3D printing make it suitable for a broad range of applications across many industries:

Automotive: MJF is used to manufacture interior components, air ducts, headlamps housings, fog lamps, reflectors, and a variety of end-use parts and tooling.

Aerospace: Lightweight customized interior parts, ducting, brackets, and functional end-use components are manufactured using MJF technology.

Industrial machinery: Functional prototypes, end-use parts like fluid system components, housings, connectors that require good mechanical performance.

Consumer goods: MJF enables small batch production of customized parts for electronics, footwear, home appliances and a variety of consumer products.

Medical: Custom surgical guides, dental aligners, orthopedic implants, patient-specific prosthetics and medical tools leverage MJF’s accuracy and biocompatible materials.

This makes MJF suitable for any industry that requires high-performance plastic parts produced in medium volumes cost-effectively. The technology is scalable for production applications and is already being used by major companies like BMW and Nike.

Multi Jet Fusion Service Providers

While HP remains the primary manufacturer of MJF printers, many 3D printing service bureaus offer professional MJF printing services. Here are some of the leading MJF service providers:

• Protolabs – One of the earliest providers of MJF, Protolabs offers automated quotes within hours and 1-15 day turnaround for MJF printed parts. They also provide mechanical testing services.
• Materialise – A 3D printing solutions provider with MJF services focused on automotive, aerospace and industrial machinery applications. Their software integration also allows streamlined ordering.
• Sculpteo – Offers MJF printing in over 15 high-performance thermoplastics with online quoting and ordering. Some materials are biocompatible for medical uses.
• HP – Through their HP 3D Printing Network, they provide access to MJF service bureaus, applications experts, and professional training services.
• Xometry – MJF printing services starting from single prototypes to mid-volume production. Can integrate well with existing supply chains.
• Stratasys Direct – A full-service bureau with advanced MJF 3D printing capabilities paired with their in-house design, engineering and finishing services.

These service bureaus allow businesses of any size to easily access MJF 3D printing without investing in in-house systems and training. Their application experts also help customers select the right materials and optimize part designs to leverage the full potential of MJF technology.

The Future of Multi Jet Fusion Printing

MJF has rapidly evolved over the past few years into one of the most viable production 3D printing technologies available today. With its productivity, part quality, and workflow advantages, MJF adoption will likely continue to accelerate across many industries.

Several developments can be expected in the future that will further improve MJF capabilities:

• New high-performance thermoplastics and composites expanding material options
• Larger build volumes and higher printer throughput for mass production
• Software enhancements for greater automation and optimization
• Improved post-processing systems integrated with MJF workflow
• Declining costs making MJF even more economical for end-use part production

As MJF continues maturing, it will become the go-to additive manufacturing method for short-run thermoplastic production in the coming years.

Conclusion

Multi Jet Fusion has proven itself as an industrial-grade 3D printing process that can viably compete with conventional manufacturing for end-use parts production. With unrivaled print speeds, part quality and mechanical performance, minimal post-processing, and increasing material options, MJF enables new applications across aerospace, automotive, consumer products and other key industries.

Both leading printer manufacturers and specialized service bureaus now provide access to MJF technology for businesses seeking to adopt 3D printing for production applications. As the technology develops further, MJF is sure to revolutionize plastic part manufacturing with its unique speed, quality and scalability advantages.