HP Multi Jet Fusion and Selective Laser Sintering both build strong PA12 nylon parts, and across the build plane their tensile strength matches. The difference shows along the build height, where an MJF part carries that strength through and a laser-sintered one does not.
We print PA12 on the HP Jet Fusion 5200, and the table below sets it against the published figures for laser-sintered PA12.
THE SHORT ANSWER
Both build PA12 nylon parts by fusing powder layer by layer. The difference is the heat source: SLS traces each part with a laser, while MJF jets fusing and detailing agents and then applies heat across the whole bed. That changes strength in Z and build time.
MJF and SLS belong to the same family of processes, powder bed fusion, and both build end-use parts and functional prototypes from PA12 nylon. In both, the loose powder around each part holds it during the build, so supports are never needed and parts can sit anywhere in the build volume.
MJF parts come out gray. Laser-sintered parts can be gray or white, depending on the powder.
Both sets of design rules are close enough that most files move between them.
In SLS, the laser is both the selector and the heat source: wherever it passes, powder fuses.
In MJF the two jobs are split. The fusing agent marks what becomes part and the detailing agent marks what must not, and only then does the heat arrive, across the whole bed at once.
MATERIAL
| Property | MJF | SLS |
|---|---|---|
| Layer thickness | 80 µm (0.003 in) | 120 µm (0.005 in) |
| Build volume | 380 × 284 × 380 mm (15 × 11.2 × 15 in) | Varies by platform |
| As-printed color | Gray, dyeable black | Gray or white, depending on powder |
| Tensile strength, XY / Z | 48 / 48 MPa (6,960 / 6,960 psi) | 48 / 42 MPa (6,960 / 6,092 psi) |
| Tensile modulus | 1,800 MPa (261 ksi), XY and Z | 1,650 MPa (239 ksi), X, Y, and Z |
| Elongation at break, XY / Z | 20% / 15% | 18% / 4% |
| Notched impact, XY / Z | Izod 3.6 / 3.5 kJ/m² (ASTM D256) | Izod 4.4 kJ/m², X (ISO 180/1A) |
| Heat deflection at 0.45 MPa | 175°C (347°F), XY and Z (ASTM D648) | 157°C (315°F) X / 145°C (293°F) Z (ISO 75) |
| Heat deflection at ~1.8 MPa | 95°C (203°F), XY and Z (ASTM D648) | 64°C (147°F) X / 57°C (135°F) Z (ISO 75) |
| Part density | 1.01 g/cm³ (0.036 lb/in³) (ASTM D792) | 0.93 g/cm³ (0.034 lb/in³) |
| Surplus powder reusability | Up to 80%, minimum 20% refresh | Not published |
The two columns come from datasheets written to different test standards, so the FAQ below sets out how far they can be compared directly. Figures come from the published material and platform datasheets for each process, the SLS layer thickness from a single documented parameter set. HP publishes its own imperial values; the rest are converted, and notched impact has no imperial figure in either column.
THE CASE FOR MJF
XY and Z
HP lists the same tensile strength and modulus for MJF PA12 across XY and Z. The published figure for laser-sintered PA12 drops in Z, so an SLS part is weaker along its build height than across it.
Elongation at break
Elongation at break falls in Z on both processes, but far less on MJF. For snap-fits and clips, orientation in the build matters less.
Under load
MJF PA12 carries a higher heat deflection temperature than laser-sintered PA12 at both the light and the heavy load each datasheet reports. Housings and brackets near motors, electronics, or warm equipment keep their shape at higher temperatures.
Voxel level
The detailing agent is deposited along the contours of every part, where it inhibits or controls fusion to keep the boundary clean and sharply defined. MJF prints embossed and engraved detail such as letters and drawings at high resolution, and the MJF design guide sets the depth those features need.
Per layer
Because MJF fuses each layer in a single pass, packing more parts into a build does not add scanning time, which makes print time predictable for any type of part. That is what makes MJF a strong fit for batch production.
Per build
Surplus powder from each build goes back into the next one, at the reuse rate the table records.
THE CASE FOR SLS
MJF vs SLS comes out differently depending on what you measure, and SLS is not the lesser process. It runs on a wider range of platform sizes, and the largest of them take a single part bigger than anything an MJF bed will hold, so an oversized part may only fit there.
If the part fits the build volume and PA12 suits the application, the MJF service page covers what the process delivers ↗FAQ
Not directly. The MJF column is tested to ASTM standards and the SLS column to ISO, with different specimen geometries, and both sets of figures are published as typical values rather than specifications. Read the table as an indication of where each process sits.
Usually not. The two processes share most of their design rules, so a file drawn for SLS prints on MJF as it stands. What to check before it goes in is the smallest detail and the smallest lettering MJF will resolve, both published in the MJF design guide.
MJF can, and the same constraint applies to any powder bed process: unfused powder sits inside any closed cavity, so a hollow part needs drain holes to get it out. HP recommends a minimum 2 mm (0.08 in) wall on hollowed models, and leaving the powder trapped is also an option, since the part comes out heavier and more resistant than the drained version.
Neither datasheet behind this comparison carries a roughness figure for PA12, so there is no number to put side by side. In both processes the orientation of each face and the finishing method have a large effect on the result. A face that pointed up in the build and the same face tumbled are two different surfaces, and the finishes we run are on the post-processing page.
Our MJF 3D printing service quotes straight from the CAD. Upload STEP, STL, IGES, 3MF, or ZIP and get an Instant Quote. Every order includes a DFM review before it goes into the build. Printed and finished in North Vancouver, British Columbia.