Multi Jet Fusion (MJF) is the process to reach for when you need nylon parts that are both strong and detailed — and you need them at production speed. It sits between SLS prototyping and injection molding: faster and more repeatable than most prototype processes, without the tooling cost of molding. This guide explains what MJF is, how it compares to alternatives, what it costs, and how to order from a vetted service bureau.
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How Multi Jet Fusion Works
MJF is a powder-bed fusion process built around speed. For each layer, the machine:
- Spreads a thin layer of nylon powder across the build bed.
- Jets a fusing agent exactly where the part should solidify — like an inkjet head printing the cross-section of your part.
- Jets a detailing agent around the edges to control heat and produce sharp, clean features.
- Passes infrared lamps over the entire layer, fusing the agent-treated powder in one sweep.
Because a whole layer fuses at once rather than being traced point by point, MJF is fast for full build plates. And because the un-fused powder supports the part as it builds, there are no support structures — complex geometries, internal channels, and nested assemblies print without design compromises or support-removal scars.
MJF vs SLS vs Metal — Choosing the Right Process
MJF vs SLS. Both are support-free powder-bed nylon processes, and for many parts they're interchangeable. MJF fuses each layer with infrared lamps, which makes it faster for full builds and gives finer detail and more consistent mechanical properties. SLS uses a laser and offers a wider material range and natural-white parts. If you're evaluating SLS, our SLS 3D printing services guide covers it in depth; for most functional nylon at volume, MJF is the faster, more repeatable choice.
MJF vs metal. When a part must carry heavy structural load, tolerate high heat, or meet metal-specific requirements, MJF isn't the answer — see our metal 3D printing services guide. But for a large share of "we've always machined this from aluminum" parts that don't actually need metal, MJF nylon is lighter, cheaper, and faster.
MJF vs injection molding. Molding wins on per-unit cost at high volume but carries thousands of dollars in tooling and weeks of lead time. MJF has zero tooling cost, so it's the better economics for low-volume runs up to a few thousand parts and for designs still likely to change.
What MJF Is Good At
- Functional prototypes that need to behave like the production part
- Low-to-mid volume end-use parts — housings, ducting, brackets, enclosures
- Jigs, fixtures, and tooling for the factory floor
- Complex geometries — lattices, internal channels, consolidated assemblies
- Batch production where nesting many parts into one build drives unit cost down
Materials and Finishes
| Material | Best for | Notes |
|---|---|---|
| PA12 (Nylon 12) | General functional & end-use parts | The default — strong, stable, chemically resistant |
| PA11 (Nylon 11) | Snap fits, living hinges, impact parts | Higher ductility and impact resistance |
| Glass-filled PA12 | Structural, heat-resistant parts | Added stiffness, less flexibility |
| TPU | Flexible parts, gaskets, grips | Elastomeric |
Standard MJF parts have a slightly textured grey surface and are commonly dyed black for a uniform finish. Bead blasting, vapor smoothing, and painting are available for appearance-grade parts.
What MJF Costs
MJF is priced by part volume and how efficiently parts nest into the build chamber — not by single-part footprint. Rough ranges:
- Small functional brackets: $15–40 each
- Mid-size enclosures: $40–150 each
- Unit cost drops sharply with quantity, because one run fills the whole powder bed
That batch economy is the whole point: a run of 50 identical parts can cost dramatically less per unit than a run of five.
How to Order MJF From a Service Bureau
Most desktop and FDM shops do not run MJF — it requires industrial HP equipment. Use these steps to find and order from a real MJF provider:
- Filter for the capability. Confirm the provider runs MJF in-house, not as outsourced work that adds lead time and markup. Browse verified providers in the directory and ask directly.
- Send a STEP file. MJF providers prefer solid CAD (STEP) over mesh (STL) for accurate quoting and nesting.
- Specify material and finish. PA12 black, dyed, smoothed — say so up front.
- Ask about tolerances. Typical MJF accuracy is around ±0.3% (with a floor near ±0.3 mm). Confirm critical dimensions before the run.
- Lean into quantity. If you'll need 50 parts eventually, quote 50 — the per-unit price often surprises people.
Our guide to choosing a 3D printing service covers the full vetting checklist.
Validate Geometry In-House First
Before committing to a production MJF run, it's worth proving form and fit cheaply. A desktop FDM printer is perfect for rough concept checks: Anycubic's desktop lineup starts under $300, and eSUN PLA+ is a forgiving filament for early iterations. Validate the design in plastic, then send the final geometry out for production-grade MJF nylon.
Order MJF Nylon Parts
Browse the 3D Prototyping Hub directory and request a quote from a vetted provider. Specify MJF, your material, and your quantity — verified shops will quote your job directly. No account required.
Hero image: Laurens van der Drift via Unsplash.