MJF – Multi Jet Fusion

What is the multi-jet fusion process?

The multi-jet process, also abbreviated as the MJF process, is one of the additive manufacturing methods. It was developed by the company Hewlett-Packard (HP). The materials used are various powder-based plastics. This type of 3D printing does not use lasers as in the polyjet process, for example, but instead uses special heat-conducting liquids known as fusion agents.

How does the multi-jet fusion process work?

As with all other additive manufacturing processes such as selective laser sintering and selective laser melting, the object is created in a CAD program prior to printing. The print data is then forwarded to the multi-jet fusion printer.

A uniformly heated powder bed (usually 80 µm thin) is applied in layers to the moving build platform in the printer. In a second step, a thermally conductive liquid, the fusion agent, is selectively sprayed onto this powder base – along the previously digitally defined shape. To form the contour, a heat-inhibiting liquid, the detailing agent, is simultaneously applied to the powder bed at the edges of the component. A lamp then heats the working area. The heat energy emitted leads to physico-chemical reactions between the powder and the two fusion agents. Where the thermally conductive agent has been sprayed onto the powder base, a solid material is created. The detailing agent ensures that the edges of the object are clear and sharp and do not blur with the unused powder outside the defined structures.  

The three work steps are repeated until the object to be printed is finished. After printing, the cured workpiece must be removed from the build chamber and the excess powder removed and cleaned manually. The object can then be reworked and finished.