What is MJF?

What is Multi Jet Fusion 3D Printing?

Multi Jet Fusion (MJF) is an Industrial 3D Printing developed by HP in 2016. It enables the creation of three-dimensional objects layer by layer from a 3D digital model. This technology creates unique parts and functional prototypes quickly and cost-effectively by using a Powder Bed Fusion. In the MJF process, the initial material, such as powdered nylon, is melted and consolidated through the use of infrared heat lamps and melting agents. The result is parts with high-quality finishes, detailed resolution and excellent mechanical properties. Because of its precision and strength, MJF 3D printing is widely used in applications requiring complex geometries and well-defined mechanical properties.

How does it work?

The MJF 3D printing process takes place through a series of key steps. These include 3D model preparation, printing and post-processing stages.

Model preparation

The process begins with the creation of a digital model, which will then be used to accurately reproduce the part. The design can easily be generated using dedicated 3D modeling software.

Preparation of the powder bed

At the sides of the printing surface, the powder is brought up. Then, a roller spreads it evenly over the entire bed in order to have a uniform thickness. As a result, the print bed is coated with a thin layer of thermoplastic powder, which serves as the base material for the process.

Printing stage

At this stage, the fusing print head applies a binder and detailing agents to the various layers of powder, which have been preheated. This agent helps melt the powder particles in the areas where the part will later be built. Meanwhile, the binder absorbs heat to help melt the powder. After the infrared light has melted the layer, the bonding agent holds the newly melted layer, ensuring solid adhesion between layers. At the same time, the detailing agent comes into action and activates an effective cooling effect. This ensures that the edges around the fused areas are sharp and accurate as well as preventing the buildup of melted powder.

Process repetition

The listed printing steps are repeated for each of the following layers. This is until the object is completed through a layer-by-layer construction.

Part extraction

At the end of printing, the solidified powder bed is taken out of the machine. The printed part remains covered with the unused powder and agent residues.

Cleaning and finishing

Excess dust and agent residues must be removed from the molded component. This can be done by brushing, blowing compressed air, or further treatment. At this point, the part may require additional finishing, such as sanding or polishing.

Materials for MJF

The rise of MJF 3D printing technology has brought a new level of versatility and precision to additive manufacturing. One factor that has strongly contributed to the success of Multi Jet Fusion is the wide range of materials it can use. This provides several options for designers to suit the needs of each part. Key materials that have proved essential to MJF's triumph include nylon PA12, nylon PA11, and nylon PA12 with glass beads (GB).

Nylon PA12

Nylon PA12, also named polyamide 12, is one of the mainstays of this technology. In fact, approximately 80 percent of MJF production is made from this material. Its excellent abrasion resistance and durability make it suitable for a wide range of industrial applications. Nylon PA12 is a versatile thermoplastic that can be molded into wear-resistant parts, functional components, and reliable prototypes. Its strength and chemical resistance make it an ideal material for parts that deal with challenging environmental conditions.

Nylon PA11

Nylon PA11, also known as polyamide 11, offers a balance of flexibility and strength. It is an excellent choice when parts need both elastic properties and good impact resistance. Nylon PA11 is often used for parts that require some flexibility, but without sacrificing durability. Its ability to withstand mechanical stresses makes it suitable for parts subjected to dynamic stresses.

Nylon PA12 GB

Nylon PA12 GB is a variant of nylon PA12, enriched with 40% glass beads. This material offers increased stiffness and strength, while maintaining low weight. Nylon PA12 GB is frequently used in industries that require lightweight but strong parts, such as the automotive and aerospace industries. It is the material with the highest thermal resistance for the MJF printer.

Why should you use Multi Jet Fusion 3D printing?

Multi Jet Fusion 3D printing technology has revolutionized the additive manufacturing scenario, with a number of advantages that make it an ideal choice for a variety of industries.

High speed production

To ensure higher speed, MJF technology constantly scans the part surface during each printing step, even when printing multiple parts at the same time. This achieves a higher build speed than other technologies, especially when working with large quantities of parts.

High accuracy

MJF technology offers exceptional precision in the creation of three-dimensional parts. This is due to timely fusion of materials and the ability to apply detailing agents in a targeted manner.

Cost-effectiveness in large-scale production

The combination of speed and precision makes MJF technology ideal for large-scale production. Furthermore, these printers have removable build volumes. This means that completed parts can be removed from the printer to allow cooling. At the same time, another build volume can be installed to maintain production continuity and enable high-volume printing. Consequently, this technology records a production capacity that is often ten times higher than the old SLS printing.

Design freedom

MJF technology does not require support structures, because the unsintered powder acts as a support structure for the part. This allows more freedom in design. Therefore, it allows the creation of complex shapes and intricate geometries that would be difficult to achieve with other printing technologies.

Versatility

Multi Jet Fusion 3D printing can be used in a wide range of industries, for example, automotive, aerospace, medicine and electronics. Its versatility makes it suitable for a variety of manufacturing and creative needs, because it provides a high rate of customization.

Sustainability

It can be a sustainable choice because it reduces material wastes. Indeed, it is capable of reusing up to 80 percent of unused powder because the detailing agent evaporates during the printing process.

Constantly improving innovation

MJF technology is constantly improving, thanks to companies continuously working to improve performance, add new materials and expand its applications.

Our MJF 3D Printing

For these reasons, MJF 3D Hub decided to select the HP MJF 5210Pro 3D printers, with an installation of 16 units. This decision was driven by a number of key advantages offered by this cutting-edge technology, outlined earlier. The decisive factor, was its demonstrated ability to combine high production speed with exceptional accuracy, satisfying the dynamic needs of the MJF 3D Hub and designers. Versatility in the use of various materials, including Nylon PA12 and PA11, provides the flexibility to meet a wide range of design requirements. High-quality finishes reduce the need for post-processing work, ensuring flawless results and efficient service. This technology choice reflects MJF 3D Hub's commitment to continuous innovation and technology leadership, positioning it as a player at the forefront of advanced additive manufacturing.