What is Multi Jet Fusion – MJF 3D Printing?

What is Multi Jet Fusion – MJF 3D Printing?

Multi Jet Fusion MJF 3d printing

3D printing technology like Multi jet fusion MJF 3d printing has come a long way in recent years, and it has revolutionized manufacturing and can change the world as we know it. However, it is also a technology that has yet to reach its full potential. There are now several different types of 3D printers to choose from. One type of the serial production grade 3D printers is MJF printer, which comes under powder bed fusion.

This type of 3D printing allows users to create intricate three-dimensional models rapidly and with precision. In this blog, we will take a closer look at the Multi Jet Fusion 3D printing technology and its advantages over other 3D printing technologies.


What is Multi jet fusion 3D printing?

Multi Jet Fusion (MJF) is HP’s proprietary 3D printing process. MJF technology is preferred by companies and industries to produce high-quality solid three-dimensional objects or parts very quickly at low price.


HP Multi Jet Fusion 3d printer at Amuse integrated factory

HP Multi Jet Fusion 3d printer at Amuse integrated factory

MJF creates fully functioning plastic parts with isotropic mechanical characteristics for precise prototype or end-use low-volume manufacturing.


How Does MJF 3D Printer works?

Multi Jet Fusion (MJF) is a 3D printing process that selectively applies fusing and detailing agents across a bed of nylon powder, which is bonded into a solid functional component in thousands of layers by the heating element. Helps produce precise and finely detailed intricate parts with powdered thermoplastics at high speed.


This method is much faster than other types of 3D printing and creates much stronger parts without adding excess weight. It is also more precise than other types of 3D printing, making it ideal for creating intricate pieces such as precision tools or delicate models.

 MJF Design Guidelines

FeatureSuggested size
Wall Thickness (Unsupported)1.0 mm (0.040”)
Wall Thickness (Supported)0.7 mm (0.030”)
Minimum detail size0.25 mm (0.010”)
Minimum hole size1.0 mm (0.040”)
Moving parts0.5 mm (0.020”) between contact surfaces
Assembly clearance0.4 mm (0.016”) between contact surfaces
Maximum wall thickness20 mm (0.8”). Higher WT shall behollowed, or honey combed inside and provide adequate escape ~8mm holes for powder removal.

What are the benefits?

MJF has several advantages when compared to other forms of 3D printing. For one, it can produce multiple components without compromising material accuracy or quality.


Material is fused together using fusing and detailing ink on the powder bed to create unique structural components or functional prototypes. MJF is perfect for creating functional parts that are long-lasting and chemical-resistant engineering thermoplastics.


MJF is a versatile technology that can be used to print parts with complex geometries and intricate details. This technology is also well suited for mass production as it can print multiple parts simultaneously.

This technology also has a wide range of applications in the medical, aerospace, and automotive industries. In recent years, there has been a growing interest in using MJF to print custom eyeglass frames and hearing aids.


It has a lot of use cases in the manufacturing and engineering sectors. This tech is useful in creating spare parts for vehicles or equipment in factories. Additionally, this can be used to create custom models for research purposes or medical purposes.


With so many applications on the rise, multi-material 3D printing seems poised to revolutionize manufacturing in the near future. 


What are the best-recommended practices when 3D printing with HP MJF?

Effective utilization of MJF 3D printing involves several key considerations, including appropriate print size, optimal wall thickness, material selection based on application, and thoughtful design choices.


For custom parts produced using MJF, it is advisable to adhere to a maximum print size of 380 x 285 x 380 mm (14.96 x 11.22 x 14.96 in). The recommended wall thickness for any MJF-created part falls within the range of 2.5 mm (0.098 in) to 12.7 mm (0.5 in). Of course, you can create a part with minimal wall thickness as low as 0.5 mm with proper iteration.


MJF excels in crafting intricate small parts and fine-detail tools, like raised text or cosmetic elements. It’s recommended to maintain a minimum feature size of 0.5 mm (0.02 in) and utilize print layers that are at least 80 microns thick (0.08 mm).


For embossing, optimal results are achieved when the part is printed upside-down and oriented upwards for engraving. When dealing with curved or hollow geometries, careful consideration is required due to the challenges posed by MJF printing. Adjusting the part design or exploring alternative additive manufacturing methods is advised.


Achieving water-resistant parts is feasible through MJF, specifically when employing PA 12 nylon powder. However, this requires walls that are a minimum of 1 mm (0.039 in) thick, or greater than 4 mm (0.16 in) for complete watertight attributes.


MJF provides cost and time efficiencies for part production, particularly in comparison to methods such as SLS and injection moulding. To optimize MJF prints, it’s vital to remain mindful of the aforementioned constraints during the design process. Additionally, factor in post-processing techniques like sanding, dyeing, or painting, as MJF parts tend to exhibit a rough and grey appearance.


Other facets and limitations of MJF that warrant consideration encompass:

  • Mitigating warping in lengthy and slender parts. Strategies include increasing part thickness, incorporating ribs in susceptible regions, substituting solid volumes with lattice structures (with a 2.5 mm (0.098 in) gap between each lattice), and implementing smooth transitions (opting for ramps over steps, for example).
  • Addressing assembly requisites. For parts necessitating post-print assembly, maintain a minimum gap of 0.6 mm (0.024 in) between connecting areas. In cases of pre-assembled parts, a recommended clearance of 0.9 mm (0.039 in) should be observed.
  • Addressing the “elephant skin” phenomenon. Thicker parts raise the likelihood of uneven curing, resulting in a pockmarked surface known as “elephant skin.” This can be mitigated by reducing wall thickness or integrating internal lattice structures.

Does it suit my industry or work?

This MJF technology is becoming increasingly popular for mass production, with some companies already using MJF to produce millions of parts. If you’re looking for a way to produce high-quality 3D-printed parts quickly and affordably, MJF may be the right technology for you.

Credits: HP 3D PrintingHubs Manufacturing


Why don't just try MJF 3D Printing yourself?