Multi Jet Fusion (MJF) 3D Printing: Complete Guide
How MJF works, how it compares to other methods, and when to use it for the best results in functional prototypes and low-volume production.
Read the ArticlePA12 (MJF) 3D Printing Material
Multi Jet Fusion (MJF) · Nylons
Fine-feature nylon for detailed, repeatable short-run production.
What Is PA12 (MJF)?
MJF PA12 produces strong, chemically resistant nylon parts with fine features and excellent dimensional accuracy and repeatability. Multi Jet Fusion builds fast across full trays, making PA12 a cost-effective choice for detailed parts and short-run production from tens to thousands of units.
Nylon Polyamide 12 - Multi Jet Fusion, printed with Multi Jet Fusion (MJF). Every order is reviewed by our engineering team - no minimum order quantity.
When to choose PA12 (MJF)
Choose MJF PA12 when you need nylon parts at production-scale consistency - fine features, tight part-to-part repeatability, and cost that improves with quantity. MJF is the process to use when you are producing 50–5,000 identical nylon parts and need each one to match the last. The full-tray build process means per-part cost drops as you fill trays, making MJF the most cost-effective powder-bed option for short-run production.
MJF PA12 and SLS PA12 have nearly identical mechanical properties - same tensile, same elongation, same chemical resistance. The differences are process-driven: MJF resolves finer features (0.5 mm vs 0.75 mm), offers slightly tighter repeatability, and builds faster at scale. SLS offers a larger build volume (up to 550 mm tall vs 380 mm) for oversized parts.
If your part needs more toughness and flexibility than PA12 provides, SLS PA11 is the ductile nylon option - MJF PA11 is not widely available. If you need chemical resistance with excellent fatigue life, MJF PP (polypropylene) is the alternative for living hinges and fluid-handling parts.
Material Properties
Representative values - process- and orientation-dependent. Full technical datasheet available on request.
Process
Multi Jet Fusion (MJF)
Tensile strength
48 MPa
Elongation at break
15–20%
Flexural modulus
1,730 MPa
Heat deflection (HDT)
175 °C @ 0.45 MPa
Density
1.01 g/cm³
Max build size
≈ 380 × 285 × 380 mm
Min wall thickness
0.8 mm
Resolution / layer
≈ 100 µm
Relative cost
$$ (1 = lowest, 4 = highest)
Design Guidelines
Plan features to print reliably and assemble cleanly in PA12 (MJF). Need DFM help?
Min wall
0.8 mm - 1.0 mm+ recommended
Min feature
0.5 mm - fine detail limit
Min hole Ø
1.0 mm - prevents powder entrapment
Drainage
≥ 2 mm holes - for hollow sections
Dimensional tolerances
Typical tolerance is ±0.3 mm or ±0.2% (whichever is greater) - slightly tighter than SLS for fine features. MJF's inkjet-based process achieves very consistent part-to-part repeatability, making it well suited to production runs where dimensional consistency matters. Post-machining is available for critical bores and mating surfaces.
Printing notes
MJF PA12 parts are produced on HP Multi Jet Fusion systems. The process uses HP inkjet technology to deposit fusing and detailing agents onto nylon powder, then fuses each layer with infrared energy. The process builds entire trays simultaneously, so per-part cost drops significantly when nesting multiple parts or producing batches. Parts emerge in a gray color due to the fusing agent; black dyeing is available for uniform cosmetic appearance. Cooling is controlled over 12–24 hours depending on tray density. The powder bed self-supports all geometry - no support structures. Orientation matters less than FDM but still affects surface finish: upward-facing surfaces are smoothest.
How PA12 (MJF) Compares
PA12 (MJF) alongside related materials.
| PA12 (MJF) | PA12 (SLS) | PP | PA11 (SLS) | |
|---|---|---|---|---|
| Tensile strength | 48 MPa | 48 MPa | 30 MPa | 47 MPa |
| Heat deflection (HDT) | 175 °C @ 0.45 MPa | 154 °C @ 0.45 MPa | 100 °C @ 0.45 MPa | 157 °C @ 0.45 MPa |
| Flexural modulus | 1,730 MPa | 1,730 MPa | 1,300–1,500 MPa | ≈ 1,100 MPa |
| Elongation | 15–20% | 15–20% | 20–30% | 40–50% |
| Density | 1.01 g/cm³ | 1.01 g/cm³ | 0.90 g/cm³ | 1.02 g/cm³ |
| Relative cost | $$ | $$$ | $$ | $$$ |
When to Use PA12 (MJF)
Where PA12 (MJF) fits, where it doesn't, and what to use instead.
Detailed functional parts with fine features
Resolves features down to 0.5 mm - finer than SLS (0.75 mm) - for parts with small text, thin ribs, and intricate snap-tab geometry.
Consumer ProductsShort-run and bridge production (50–5,000 units)
Full-tray builds produce 50–200+ parts per run with <2% part-to-part variation, making MJF the most repeatable powder-bed process for production.
Consumer ProductsComplex housings and ducting
Powder-bed self-support prints internal baffles, channels, and undercuts impossible in FDM - same design freedom as SLS with faster throughput.
EngineeringSnap-fits, clips, and living hinge assemblies
15–20% elongation handles snap-arm deflection through hundreds of assembly cycles, and MJF's dimensional consistency keeps interference fits repeatable across production batches.
Consumer ProductsEnd-use components at production volumes
Per-part cost drops 40–60% at 100+ units compared to FDM, with no tooling investment - fills the gap between prototyping and injection molding.
EngineeringStrengths
- Finest feature resolution of any powder-bed process in our catalog (0.5 mm vs SLS's 0.75 mm) with ±0.3 mm / ±0.2% tolerance
- Full-tray production builds 50–200+ nylon parts per run - fastest throughput and lowest per-part cost at volume in our nylon catalog
- Same 48 MPa tensile and near-isotropic properties as SLS PA12 with better dimensional consistency across batch runs
Keep in mind
- As-printed surface is gray from fusing agent - dye black for uniform cosmetic finish (no dimensional change, adds 1–2 days)
- Hollow sections trap powder - design ≥2 mm drainage holes in every enclosed cavity; MJF powder is finer than SLS and harder to fully evacuate
- Smaller build envelope than SLS (380 x 285 x 380 mm vs 350 x 350 x 550 mm) - parts taller than 380 mm must go to SLS or be split
Finishes & Colors
Finishing options and in-stock colors for PA12 (MJF).
Standard
De-powdered, matte gray finish.
Best for: Functional parts
Dyed Black
Uniform black; no dimensional change.
Best for: Cosmetic uniformity
Media Tumbled
Smoother satin surface.
Best for: Handled parts
In-Stock Colors
Gray
Black (dyed)
Custom colors and dyeing available on request. Contact us for options.
PA12 (MJF) FAQ
Both make strong nylon parts. MJF typically gives finer features, better repeatability, and faster throughput for short runs; SLS offers a larger build volume and a slightly different surface. We'll recommend the best fit on quote.
MJF is cost-effective from roughly 50 to several thousand units thanks to fast full-tray builds, while still working for one-offs.
MJF PA12 is significantly stronger (48 MPa vs 33 MPa tensile), more isotropic, and more chemically resistant than FDM ABS. PA12 also has higher heat deflection (175 °C vs 87 °C). The trade-off is cost: FDM ABS is cheaper for simple geometries, but MJF becomes cost-competitive at 20+ units.
As-printed MJF PA12 is gray. We offer black dyeing that penetrates the surface for a uniform cosmetic finish with no dimensional change. Custom colors are not standard but can be achieved with primer and paint.
MJF PA12 parts are slightly porous as-printed. For watertight applications, parts can be sealed with infiltrants or coatings. Design walls at 2.0 mm+ minimum and specify watertight requirements at quote.
We hold ±0.3 mm or ±0.2%. MJF achieves excellent part-to-part repeatability, making it the best powder-bed process for production runs where dimensional consistency matters across dozens or hundreds of parts.
MJF PA12 is the most cost-effective powder-bed option for production volumes. Per-part cost drops significantly at 50+ units as the full-tray build amortizes setup time. For 500+ units, compare with injection molding - but MJF eliminates tooling cost, so the break-even depends on geometry and annual volume.
No. Like SLS, MJF PA12 is printed in a self-supporting powder bed. There are no supports to remove, no support marks, and complete design freedom for internal channels, undercuts, and nested assemblies.
Technical Documents
Related Articles
How to Choose the Right MJF Materials for Functional Prototypes and Production Parts
Many failures come from excessive deflection, creep, or cracking rather than lack of strength. Understanding PA12, PA11, glass-bead PA12, TPU, and FR grades.
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