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SLS vs MJF
Quick answer
SLS and MJF print the same nylon family with comparable strength; they differ in how they fuse powder and what that implies. MJF fuses whole layers at once (fast, consistent, near-isotropic; parts come out grey, usually dyed black) and is tied to HP's focused material set. SLS scans a laser (slower on dense layers) but offers the widest material range — PA12, PA11, glass-filled PA12, PA6 — the widest machine range, and white parts that dye any colour. Pick MJF for repeatable volume in PA12; pick SLS for material choice and flexibility.
Side by side
| Aspect | SLS | MJF |
|---|---|---|
| Fusing method | Scanning laser (CO₂ or fibre, per machine data sheets) | Jetted fusing/detailing agents + infrared exposure |
| Flagship PA12 datasheet | EOS PA 2200: 48 MPa tensile, 1650 MPa modulus, 18% elongation (XY) | HP HR PA 12: 54 MPa tensile, 2150 MPa modulus, 18% elongation (XY) |
| Z-direction behaviour | Published penalty: PA 2200 falls to 42 MPa and 4% elongation in Z | HP lists equal XY/Z tensile strength and modulus; elongation 18% (XY) vs 10% (Z) |
| Materials range | Broad: PA12, PA11, glass-bead PA12, PA6, from multiple suppliers | Focused: HP PA 12, PA 11, PA 12 Glass Beads |
| As-built colour | White / off-white; dyes to any colour | Grey; most commonly dyed black |
| Layer time | Scales with cross-section area scanned | Fixed per layer, independent of content |
| Machine landscape | EOS, Formlabs, Farsoon, Sinterit and others; desktop-class to large industrial | HP Jet Fusion series only |
| Supports | None in either process — the powder bed supports the parts; both need escape holes for hollow parts (see the design guide) | |
Material figures are the manufacturers' published values from the data sheets cited on the PA 2200 and HP PA 12 pages; test methods differ between manufacturers. Other rows are qualitative descriptions of how the two processes work — see the SLS and MJF pages.
When SLS wins
- You need a material MJF does not offer — glass-filled stiffness (PA 3200 GF), PA6 heat resistance (Ultrasint PA6), or a specific PA11 grade.
- Colour matters: white parts and full-colour dyeing.
- You are buying a machine and want choice across sizes and budgets, including compact systems like the Fuse 1+ 30W.
When MJF wins
- Repeatable production in PA12: fixed layer times and HP's integrated powder workflow favour full, nested builds.
- You value the published isotropy — equal XY/Z strength on the PA 12 data sheet — for parts that cannot be oriented freely.
- Your parts will be dyed black anyway, which is MJF's home turf.
The honest summary
For most PA12 functional parts, either process produces a good part, and the deciding factor is usually which capacity is available at the right price and turnaround. The processes diverge at the edges — unusual materials, colour, extreme isotropy requirements, fleet economics — and those edges are where this comparison should be applied.
Frequently asked questions
Is MJF stronger than SLS?
On flagship PA12 datasheets the numbers are close: HP lists 54 MPa tensile strength for MJF PA 12 with equal XY and Z values, while EOS lists 48 MPa (XY) / 42 MPa (Z) for SLS PA 2200. Different test setups prevent a strict verdict, but MJF's published isotropy is real, and SLS closes much of the gap with PA11 where ductility matters.
Which is cheaper, SLS or MJF?
It depends on volume and packing. MJF's layer time is fixed regardless of content, so full builds are very economical per part at volume; SLS has a broader machine price range, from desktop-class units to large industrial systems, and a wider second-hand/service market. For one-off parts, bureau pricing usually reflects whichever capacity they run — get both quotes for production work.
Can SLS and MJF parts be used interchangeably?
Often, for PA12 functional parts of moderate precision — the materials are close cousins. Watch three things: colour (SLS white vs MJF grey), surface feel, and any feature designed exactly at one process's minimums. Re-validate critical dimensions on the new process.
Last updated: November 2026