DefinitionMulti Jet Fusion (MJF) is a powder bed fusion 3D printing process that builds polymer parts, most often nylon PA12, by jetting a fusing agent and a detailing agent onto each layer of powder, then exposing the layer to infrared energy.
Explained
Multi Jet Fusion (MJF) is a powder bed fusion 3D printing process that builds polymer parts, most often nylon PA12, by jetting a fusing agent and a detailing agent onto each layer of powder, then exposing the layer to infrared energy. It is a close relative of selective laser sintering (SLS), which fuses powder with a laser instead.
How Does Multi Jet Fusion Work?
Each layer starts with a roller spreading fresh powder across the build platform. Print heads then apply two liquids:
- a fusing agent where the part should be, which absorbs infrared energy, and
- a detailing agent around the edges, which limits fusion so the outline stays sharp.
An infrared source then sweeps over the whole bed. The powder under the fusing agent heats up and sinters, and the untreated powder stays loose. The platform lowers and the cycle repeats. One published study gives a layer thickness of around 80 µm (0.003 in).
The key difference from SLS is that in MJF the heat source does not melt the polymer directly. Sintering starts when the fusing agent absorbs infrared energy. The process was introduced commercially in 2014. Under ISO/ASTM 52900 it belongs to powder bed fusion, in the subgroup that fuses with "agent and energy" rather than a scanning laser.
The range of certified MJF materials is still limited. One study lists PA12, PA11, glass-bead-filled PA12, polypropylene and TPU.
MJF vs SLS
| Aspect | MJF | SLS |
|---|---|---|
| ISO/ASTM category | Powder bed fusion | Powder bed fusion |
| How each layer is fused | Fusing and detailing agents jetted onto the powder, then the whole layer is exposed to infrared | A laser scans each cross-section and sinters the powder inside its boundary |
| Typical layer | Around 80 µm (0.003 in) in one published study | 100–180 µm (0.004–0.007 in) at NICE Rapid |
| Common materials | PA12, PA11, glass-bead-filled PA12, PP, TPU | PA12, PA11, glass-filled and carbon-filled PA12, TPU (NICE Rapid range) |
| Origin | Introduced commercially in 2014 | Patented by Carl Deckard, University of Texas (filed 1986) |
| At NICE Rapid | Not among our in-house processes | In-house, ±0.2 mm (±0.008 in), 2–3 day lead time |
Choosing Between MJF and SLS
For most functional nylon parts, such as housings, brackets, snap fits and assemblies, the two processes are alternatives, and the choice comes down to material, availability and lead time. Keep these points in mind:
- Specify the material and properties, not only the process. If a drawing says "MJF PA12," check whether the requirement is really a PA12 nylon part with certain mechanical properties. An SLS PA12 part may meet the same need.
- Mind build orientation. Studies disagree on how much print orientation affects MJF tensile properties. One study found that vertically oriented parts performed better because they received more infrared sweeps. Agree on orientation for load-bearing parts.
- Accuracy is a trade-off. One dimensional-accuracy study found that the settings giving the best geometric accuracy also increased interlayer porosity. Confirm critical dimensions with a sample.
NICE Rapid does not list MJF among its in-house processes. For functional nylon parts, our comparable in-house process is SLS 3D printing.
Key takeaways
- MJF is a powder bed fusion process that builds polymer parts by jetting a fusing agent and a detailing agent onto each powder layer, then fusing with infrared energy.
- The fusing agent absorbs infrared energy to start sintering, while the detailing agent inhibits fusion at edges for sharper outlines.
- MJF was introduced commercially in 2014 and is classified under ISO/ASTM 52900 as powder bed fusion by agent and energy.
- Typical MJF layer thickness is around 80 µm (0.003 in) according to one study.
- Common certified MJF materials include PA12, PA11, glass-bead-filled PA12, polypropylene and TPU.
- Print orientation can affect tensile properties; one study found vertically oriented MJF parts performed better because they received more infrared sweeps.
- Settings that maximize geometric accuracy may increase interlayer porosity, so critical dimensions should be validated with samples.
- NICE Rapid does not offer MJF in-house; SLS 3D printing is the comparable in-house route for functional nylon parts.
Example
Related terms
References
- Lee & Kajtaz, "Experimental Characterisation and Finite Element Modelling of Polyamide-12 Fabricated via Multi Jet Fusion," Polymers — Polymers
- Adach et al., "Study on Geometry, Dimensional Accuracy and Structure of Parts Produced by Multi Jet Fusion," Materials — Materials
- Koltsaki et al., "A Comprehensive Overview of Additive Manufacturing Processes Through a Time-Based Classification Model," 3D Printing and Additive Manufacturing — 3D Printing and Additive Manufacturing
- US Patent 4,863,538 — Method and apparatus for producing parts by selective sintering — patents.google.com
- Perez-Barcenilla et al., "Applicability of a Material Constitutive Model Based on a Transversely Isotropic Behaviour for the Prediction of the Mechanical Performance of Multi Jet Fusion Printed Polyamide 12 Parts," Polymers — Polymers