Multi Jet Fusion, usually shortened to MJF, is HP's polymer powder-bed 3D printing technology. It combines powder, selectively applied agents and heat to make parts layer by layer. Manufacturers use it for prototypes and production parts where the selected material and process meet the application's requirements.
For a buyer, the useful questions are straightforward: how does it work, what can it make, and what must be checked before placing an order?
How the MJF process works
A recoater spreads a layer of powder. Inkjet arrays apply fusing and detailing agents, and a heat source acts on the layer to fuse selected areas. The machine repeats the sequence to build the geometry. HP distinguishes this from SLS, which uses a laser, and binder jetting, which deposits a binder. See HP's process comparison.
The surrounding powder supports the parts during printing, so MJF polymer parts generally do not require attached support structures. That does not remove all design constraints: trapped powder, access for cleaning, thin features and part orientation still need consideration.
After printing, the build cools before unpacking. Parts then need powder removal and any specified finishing or inspection. Include those steps when discussing delivery dates; printing time is only one part of turnaround.
Materials: specify the grade, not just “nylon”
PA 12 and PA 11 are examples of materials offered for MJF, with other options available for particular systems. Compatibility and properties depend on the material grade and machine. Check the current HP materials portfolio and the supplier's available combinations.
A family name does not establish fitness for use. Ask for the relevant material data and identify what matters for the part: stiffness, impact behavior, temperature, chemical exposure, appearance or flexibility. Consider the finished part and its processing conditions rather than assuming bulk-material data transfers unchanged.
Do not assume that a printer can run every reinforced or flexible powder, or that an MJF part has identical properties in every direction. Have the supplier assess the actual geometry, orientation and requirements.
Applications that can suit MJF
A prototype may need a usable housing or assembly component. A production job may need multiple variations or recurring small batches. A replacement-part program may value an approved file that can be reordered when needed.
These are application patterns, not universal guarantees. A visual model, a loaded fixture and a part exposed to heat can require different materials and acceptance checks even when their shapes look similar.
For the commercial implications of combining different orders in a shared build, read the business case for MJF.
Design and finish need to be agreed together
Discuss minimum walls, gaps, holes and unsupported features with the manufacturer using guidance for the selected system and material. There is no single feature-size or wall-thickness figure that guarantees every MJF design will work. HP's MJF handbook provides process-specific design topics to review.
Decide which surfaces are cosmetic, which dimensions must be inspected and which mating features are important. Powder removal needs access to internal spaces. A part that can be printed may still be difficult to clean or inspect.
Finishing can include blasting, dyeing or other treatments offered by the supplier. Specify the required result and ask how the treatment affects appearance, dimensions and function. Do not assume that dyeing, sealing or smoothing is included in a basic quote.
Comparing MJF with another process
Compare the complete job: accepted parts, material, finish, quantity and delivery requirement. A claim that one technology is always faster, stronger or cheaper is not a useful purchasing rule.
For an early shape check, another prototype process may answer the question sooner. For an established production part, material qualification and consistency may matter more than the nominal print speed. For larger quantities, include tooling-based options where appropriate.
Ask each supplier to quote the same requirement and explain any proposed substitution. That makes the comparison more meaningful than comparing process names alone.
A useful MJF request checklist
Send the file revision, quantity, intended use, material preference, finish, critical dimensions, inspection requirements and required date. Identify which requirements are fixed and where you welcome advice.
Phasio supports the business workflow around such jobs through additive quoting and production management. The manufacturing supplier remains responsible for selecting and controlling the production process.
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