MJF (Multi Jet Fusion)

HP introduced MJF in 2016, leveraging its inkjet expertise. For each layer, the printer spreads nylon powder, then an inkjet carriage prints two agents: a fusing agent on the cross-section of the part, and a detailing agent on the surrounding boundary to keep edges sharp. An IR lamp passes over the bed; the inked fusing regions absorb heat and melt together, while the surrounding powder stays loose.

Like SLS, MJF needs no support material — unfused powder supports overhanging features. After cooling, parts are broken out and bead-blasted clean.

MJF is faster than SLS for medium-to-large production runs because the IR pass fuses a whole layer at once, rather than scanning point-by-point with a laser. Service bureaus like Shapeways and Protolabs use MJF heavily for end-use plastic parts.

MJF parts have slightly darker color than SLS parts (the fusing agent is dark) and can be dyed easily. Mechanical properties are comparable — strong, isotropic, dimensionally stable.

MJF and SLS are close enough that most service-bureau workflows treat them as substitutable. The choice usually comes down to available capacity and pricing rather than print quality. Both produce nylon parts you can use functionally.