Multi Jet Fusion (MJF)

Multi Jet Fusion (MJF) builds strong, functional polymer parts by fusing powder with inked agents and heat, delivering fine detail and consistent batch properties.

Overview

Multi Jet Fusion (MJF) is a powder-bed plastic 3D printing process where a printer jets fusing and detailing agents onto thin layers of polymer powder, then uses heat to fuse the selected regions. Parts come out of a powder cake, then get depowdered and typically bead-blasted; dyeing and vapor smoothing are common secondary finishes.

Choose MJF for functional prototypes and end-use parts that need good strength, repeatability, and economical batch production. It excels at complex geometries, lattices, and assemblies printed in one build, with no support structures and efficient “nesting” of many parts.

Tradeoffs: surfaces are typically matte/grainy unless post-processed, thin features can be fragile, and accuracy depends on orientation and consistent wall thickness. Material choice is narrower than some photopolymer processes, and tight cosmetic requirements often need finishing steps.

Common Materials

  • PA12
  • PA11
  • PA12 GF
  • TPU 88A
  • PP

Tolerances

±0.010 in (±0.25 mm) up to ~4 in, then ±0.2%

Applications

  • Snap-fit housings and enclosures
  • Ducting and fluid/air manifolds
  • Functional brackets and mounts
  • Lattice pads and energy absorbers
  • Low-volume end-use consumer product parts
  • Jigs, fixtures, and assembly tooling

When to Choose Multi Jet Fusion (MJF)

MJF fits low-to-medium volume production and functional prototyping where strength, repeatability, and complex geometry matter more than a glossy cosmetic surface. It’s a good choice when you want many parts per build with minimal labor (no support removal) and stable mechanical properties across a batch.

vs Fused Deposition Modeling (FDM)

Choose MJF when you need more consistent mechanical properties, finer feature resolution, and better dimensional repeatability across a batch. MJF also avoids support scars on internal channels and nested assemblies that are difficult to post-process in FDM.

vs Stereolithography (SLA)

Choose MJF when parts need ductile, impact-resistant thermoplastic behavior and better long-term durability. SLA wins on ultra-smooth surfaces and very fine cosmetic detail, but MJF is usually stronger for functional brackets, housings, and snap features.

vs Selective Laser Sintering (SLS)

Choose MJF when you want higher throughput and strong batch-to-batch consistency at production volumes, especially for dense nesting. SLS is comparable for geometry freedom and materials, but MJF often delivers tighter process control and more uniform properties within a build.

vs Digital Light Processing (DLP)

Choose MJF for functional thermoplastic parts and production-like performance rather than brittle/UV-sensitive photopolymers. DLP can be faster for small, highly detailed cosmetic parts, but MJF is typically better for rugged end-use nylon components.

vs PolyJet

Choose MJF when you need durable nylon parts at lower cost per part and better mechanical performance. PolyJet is better for smooth cosmetic models and multi-material/overmold-like prototypes, but parts are generally not as tough as MJF nylon.

Design Considerations

  • Keep wall thickness consistent; avoid abrupt thick-to-thin transitions to reduce warp and sink-like distortion
  • Size holes undersized and plan to drill/ream critical diameters; treat as-printed holes as pilot features
  • Avoid long, thin cantilevers; add ribs or gussets for stiffness instead of increasing wall thickness everywhere
  • Orient and place cosmetic faces away from powder-contact and depowdering access areas; plan for bead-blast/dye variation
  • Call out critical datums and tolerances only where needed; expect secondary machining for tight fits and sealing surfaces
  • Design escape paths and access for depowdering internal cavities; trapped powder can add weight and rattle