MJF (Multi Jet Fusion): HP's powder printing

How MJF works

The printer spreads a layer of powder, usually polyamide, and jets an agent that absorbs heat better onto the places where the part is to form. A heat source then passes over, and exactly the marked area fuses. The remaining powder stays around the part and supports it, so no supports are needed. The technology belongs to the powder sintering processes, like SLS, but a whole layer is processed at once rather than point by point.

What makes MJF interesting

• Speed for batches. Many parts are packed into one machine and printed at the same time.
• Consistent properties. Parts are strong in every direction, with no weak bonds between layers.
• Detail. Fine details, thin walls and moving assemblies come out better than with ordinary filament printing.
• Grey finish. Parts come out dark grey and slightly grainy.

The drawback is the high cost of the machines, which is why MJF is offered by specialist manufacturing services, not by home workshops.

What this means for your order

We do not print MJF. We print with FDM in PLA and PETG. If you need something else, write to jakub.novak@boostello.com. We do not promise a print in advance, but we can advise.

For small batches of functional parts our FDM is usually good enough. You see the price and lead time straight after uploading your model, with no waiting for a quote. For very large runs or parts with the finest detail, MJF is the better fit, and we do not take those jobs.

What MJF requires from a model

A hollow MJF part needs openings through which the unsintered powder can be shaken out, and clearance has to be left between moving parts. You will know similar rules from tolerances in FDM too. If you have a model prepared for MJF and want to print it with us, bear in mind that with FDM you need to pay more attention to overhangs and thin walls. The simplest thing is to upload the model to the calculator, where you see the real price and lead time.