Summary of Multi Jet Fusion (MJF) 3D Printing materials and process

Multi Jet Fusion is an industrial 3D printing technique that delivers functional nylon prototypes and end-use production parts as fast as in 1 day. The terminal products have excellent quality in surface finishes, higher feature resolution, and ‬more consistent mechanical properties than other 3D printing methods like selective laser sintering.

What is MJF 3D printing?

MJF(Multi Jet Fusion), a new technology in 3D printing released by HP in 2016, aims to help users solve these three problems – speed, precision, and cost. According to HP, it is ten times faster than the other 3D printing technology with the same precision and strength. Now MJF 3D printing is widely used in various areas.

How Does Multi Jet Fusion Work?

Multi Jet Fusion uses an inkjet array to selectively apply fusing and detailing agents across a bed of nylon powder, which will be fused by heating elements into a solid layer. Then, the same process is repeated until the part is finished.

After that, the powder bed with the encapsulated parts is moved to a processing station, where most of the loose powder is removed in an integrated vacuum. Parts are then bead blasted to remove the remaining residual powder before ultimately reaching the finishing department, where they are dyed or for future processing to improve cosmetic appearance.

Why choose Multi Jet Fusion?

Multi Jet Fusion uses fine-grained materials supporting ultra-thin layers of 80 microns. It leads to parts with high density and low porosity, compared to parts produced with Laser Sintering. It also leads to an exceptionally smooth surface straight out of the printer, and functional parts need minimal post-production finishing. That means a short delivery time, ideal for functional prototypes and a small series of end products.

Multi Jet Fusion Materials

Initially, Multi Jet Fusion was only compatible with Nylon PA 12 powders. And it is still the most common option. The breadth of available materials has expanded in the few years the technology has been on the market, with new ones still on the way. Although Multi Jet Fusion is a type of powder bed fusion, that doesn’t mean all powder bed compatible materials will work with MJF. The material list for MJF is much shorter than powder bed fusion. Because it’s a property HP process, material manufacturers are responding to the MJF’s growing popularity. In 2020, HP worked with BASF to develop a chemical-resistant polypropylene.

MJF-COMPATIBLE MATERIALS INCLUDE:

High Reusability (HR) PA 12 Nylon
HR PA 12 Glass Bead (GB)
HR PA 11
Estane 3D TPU – M95A from Lubrizol
Ultrastint TPU01 from BASF/Forward AM
TPA from Evonik/HP
Vestosint 3D Z2773 PA 12 from Evonik/HP

Ideal applications for Multi Jet Fusion

Low-volume production of complex end-use parts

Prototypes for form, fit, and function testing

Prototypes with mechanical properties to rival those of injection-molded parts

Small components as a cost-effective alternative to injection molding

Advantages of Multi Jet Fusion

Fast printing speed and production cycle

Accurate printing for fine details

Low print cost for individual

Freedom design and no technique supports are needed

Few warping in the printing process

Less waste due to powder recycling

Colored parts production supported

High-quality surface finish

Consistent mechanical properties

High chemical resistance

HP’s property polypropylene

Disadvantages of MJF 3D Printing

High initial printer investment

Unable to produce some curved, hollow geometries

The final product is a blotchy gray

Small raised text and cosmetic parts may be lost in post-processing

WKproto offers 3D printing services worldwide, if you need a MJF 3D printing service, contact us now!