The Best of Both Worlds
Most 3D printing forces a trade-off: you can have strong, functional thermoplastic parts (FDM) or smooth, detailed parts (SLA) — but not both.
HP’s Multi Jet Fusion changes that equation.
MJF builds parts from real thermoplastic nylon powder (PA 12, PA 11, or TPU) using a chemical sintering process. The result is a part that’s genuinely strong, dimensionally accurate, and smooth enough to use without heavy post-processing. Most importantly, MJF parts are fully dense with zero porosity — meaning they’re airtight and watertight out of the machine.
That’s a combination no other process delivers at this price point.
How MJF Works
Unlike FDM (which extrudes filament) or SLA (which cures liquid resin), MJF works with a powder bed:
- A thin layer of nylon powder is spread across the build platform
- An inkjet array selectively deposits fusing and detailing agents onto the powder
- An infrared energy source passes over the bed, fusing the areas where agent was applied
- The platform lowers, a new layer of powder is spread, and the process repeats
The detailing agent is what gives MJF its edge — it’s applied at part boundaries to create sharp edges and fine features while the fusing agent handles structural integrity.
When to Choose MJF
MJF excels when you need:
- Watertight or airtight parts — zero porosity means fluid and gas containment without post-processing or sealing. Housings, manifolds, fluid channels, enclosures.
- Functional nylon parts — real PA 12 nylon with excellent mechanical properties. Not resin, not PLA — actual engineering thermoplastic.
- Good surface finish AND strength — SLA-like smoothness with FDM-level durability.
- Complex internal geometry — powder bed processes don’t need support structures for overhangs, so you can design internal channels, lattices, and geometries that would be impossible with FDM or SLA.
- Small to mid-volume production — MJF’s build speed and powder packing density make it cost-effective for runs of 50–500+ parts.
- Snap fits, living hinges, and functional features — nylon’s flexibility and fatigue resistance make it ideal for mechanical features.
Real-world applications:
- Fluid handling components for industrial equipment
- Custom enclosures that need to be sealed against dust or moisture
- Automotive intake manifolds and ducting
- Production-grade jigs and fixtures
- Consumer product housings going directly to market
MJF Materials
| Material | Properties | Best For |
|---|---|---|
| PA 12 (Nylon 12) | Strong, stiff, excellent detail. The workhorse. | Functional prototypes, production parts, enclosures |
| PA 11 (Nylon 11) | More ductile than PA 12, higher elongation at break | Living hinges, snap fits, impact-resistant parts |
| PA 12 Glass Bead | 40% glass bead fill. Higher stiffness and thermal resistance | Structural parts, high-temp applications |
| TPU (Thermoplastic Polyurethane) | Flexible, rubber-like. Shore 88A hardness | Gaskets, grips, vibration dampening, wearables |
MJF vs. Other Processes
MJF vs. FDM
- MJF wins on: Surface finish, isotropy (equal strength in all directions), zero porosity, complex internal geometry
- FDM wins on: Larger build volumes, wider material range (ULTEM, PC-ISO, ABS), lower cost for single large parts
- Choose MJF when: You need sealed/watertight parts, better aesthetics, or isotropic strength
MJF vs. SLA
- MJF wins on: Material strength (real thermoplastic vs. cured resin), durability, UV resistance, production suitability
- SLA wins on: Finer detail resolution, transparent/clear materials, lower cost for small one-off parts
- Choose MJF when: The part needs to function, not just look good
MJF vs. SLS
- MJF wins on: Surface finish, build speed, cost per part at moderate volumes, color capability (with CB PA 12)
- SLS wins on: Wider material selection (glass-filled nylons, flame-retardant variants), larger single-part builds
- Choose MJF when: Surface finish matters and you’re running mid-volume production
How PartSnap Delivers MJF
We source MJF production through our qualified manufacturing network — the same partners we trust for injection molding, CNC machining, and other production processes. You get:
- Engineering oversight — we review your design for MJF-specific considerations (minimum wall thickness, escape holes for trapped powder, feature resolution) before it goes to production
- Process selection guidance — we’ll tell you honestly whether MJF is the right call or if FDM, SLA, or another process makes more sense for your specific application
- Single point of contact — you deal with PartSnap, not a print farm. We manage quality, timeline, and delivery.
Get an MJF Quote
Tell us about your project. Upload your STL or STEP file and we’ll recommend the right process — whether that’s MJF, FDM, SLA, or something else entirely.
info@partsnap.com · 214.449.1455