| Attribute |
What actually happens |
Verdict |
| Cost & nesting |
SLS is usually the cheaper route at volume. Because SLS nests parts more densely through the build, more parts share each build and the cost per part drops faster as quantities rise. MJF can be competitive on single items and lighter, less dense parts, but for a full production nest SLS typically comes out cheaper. We quote both and show you the cheaper one. |
SLS wins |
| Strength |
Close on standard PA12. MJF is marginally more isotropic, so Z-direction strength holds up a touch better — our figures put SLS PA12 around 42 MPa tensile and MJF PA12 around 48 MPa. For a real step up in stiffness and heat, SLS filled grades leave both standard nylons behind. |
Comparable |
| Ductility & elongation |
SLS is the more ductile process — SLS nylons stretch further before they break, so parts that need to flex, snap-fit or absorb a knock hold up better. More forgiving on standard PA12 and especially on PA11, where high elongation makes SLS the pick for living hinges, clips and impact parts. |
SLS wins |
| Accuracy |
Both hit tight tolerances, typically in the region of ±0.3 mm per 100 mm, with in-house scaling refined over years of production. In practice they measure near-identically across our machines. |
Comparable |
| Material range |
SLS runs the wider range by far: PA12, glass-filled PA12-GF, carbon-filled PA12-CF, PA11 and flexible TPU 90A. MJF is a focused production trio — PA12, PA11 Gen2 and TPU 01. If you need a filled or specialty grade, SLS is the answer. |
SLS wins |
| Colour range |
SLS parts come out light and take dye across a range of colours. MJF comes out grey and is dyed black. If you need anything other than black, SLS is the route. |
SLS wins |
| Black colour depth |
When black is what you want, MJF is dyed right through the part, so a scratch or a machined edge stays black. Surface-dyed SLS colours the outer skin only, which can show lighter if the part is scuffed or cut. |
MJF wins |
| Fine features & small holes |
MJF is a touch crisper on very fine detail and text, and small holes under about 5 mm come out rounder and truer. SLS holds fine features well but can render the smallest holes very slightly elliptical. |
MJF wins |
| Thick & solid parts |
On chunky sections (roughly 20 mm and thicker) MJF can show “elephant skin” — a rippled outer surface from uneven powder dosing that can also weaken the part. SLS handles solid parts more cleanly, which makes it the safer pick for heavy, blocky geometry. |
SLS wins |
| Weight |
SLS parts are lighter — PA12 comes out around 0.95 g/cm³ against roughly 1.01 g/cm³ for MJF. Where every gram matters, SLS has the edge. |
SLS wins |
| Surface finish |
Both give a fine, matte, support-free surface, and both can be dyed, vapour smoothed or shot-peened in-house. Line-ball between them. |
Comparable |
| Repeatability at volume |
Both produce identical, repeatable parts at production volume — SLS is every bit as capable of hundreds of consistent end-use parts as MJF. MJF’s layer-at-once fusing gives it a slight reputational edge on surface uniformity across very large batches, but for part-to-part consistency the two are on a par. |
Comparable |
| Lead time |
SLS offers express turnaround from 1–3 days. MJF production typically runs 5–7 days once cooling, de-powdering, finishing and inspection are counted in. Need it fast? SLS. |
SLS wins |
