HP - Multi Jet Fusion (MJF)

Multijet Fusion (MJF) Printer
MJF Part in Nylon

Multi Jet Fusion (MJF) uses a fine grained PA12 material that allows for ultra thin layers of 80 microns to be deposited. This allows for parts with a high density and low porosity to be manufactured compared with those produced by laser sintering. It leads to an exceptionally smooth surface straight out of the printer, and functional parts need minimal post-production finishing. That means short lead times, ideal for functional prototypes and small series of end parts. Ideal applications for MJF include low volume production of complex end-use parts, prototypes for form, fit and function testing, prototypes with mechanical properties to rival those of injection- moulded parts, series of small components as a cost- effective alternative to injection moulding

A thin layer of powder is first spread over the build platform where it is heated to a near-sintering temperature.

 A carriage with inkjet nozzles (which are similar to the nozzles used in desktop 2D printers) passes over the bed, depositing fusing agent on the powder. At the same time a detailing agent that inhibits sintering is printed near the edge of the part.

A high-power IR energy source then passes over the build bed and sinters the areas where the fusing agent was dispensed while leaving the rest of the powder unaltered. The process repeats until all parts are complete.

Similar to SLS, the printed parts are encapsulated in powder and need to cool down before they can be removed.

Advantages of MJF

Print in different materials PA11 (ductile, quality parts), PA12 (strong, low-cost parts), PA12 40% glass bead-filled (stiff, low-cost quality parts)

High-quality prints at lower costs

High production speed

Disadvantages of MJF

Surface quality is good, but rougher than that produced by photopolymer based technologies (Stereolithography).

The raw parts are grey; these parts can easily be dyed black, but other colors require coating (at extra cost).

Limited materials