MJF vs SLS: A Complete Comparison for Industrial 3D Printing Applications

Powder-bed printing is now the go-to for serious production parts made from plastic powder. The two big names everyone actually uses in 3D printing are Multi Jet Fusion (MJF) and good old Selective Laser Sickness (SLS).

Both run on nylon powder and both can make real end-use parts, not just prototypes. That’s why people always end up asking: “Which one should I pick?”.

This guide, based on real-world production experience from Momaking — a leading MJF and SLS 3D printing service provider in China — provides engineers, OEMs, and industrial buyers with a practical technical comparison of MJF vs SLS.

How Each One Actually Works

1. Multi Jet Fusion (MJF)

3D printing machine spreads powder, sprays fusing agent where you want solid plastic, sprays detailing agent where you don’t want it to melt, then flashes the whole bed with infrared lamps. Boom—one layer done, super fast. Typical materials: PA12, glass-filled PA12, and PP. Parts come out dark gray (never pure black fresh off the printer). You can dye them black or pretty much any color afterward. Why people love it: crazy fast print times, parts look and feel the same no matter where they sit in the bed, almost zero porosity, strong, and actually watertight.

2. Selective Laser Sintering (SLS)

Classic laser machine. Roller lays down powder, laser draws the shape dot by dot, bed stays hot the whole time. When the job finishes you have to wait hours for everything to cool slowly so parts don’t warp. Material menu is huge: PA11, PA12, carbon-fiber nylon, glass-filled, TPU for rubber-like parts, flame-retardant grades—you name it. Fresh parts are matte white. Strength is perfectly even in all directions, especially with PA11 or filled materials.

3. The Real Difference

MJF heats the entire layer at once. SLS heats one tiny spot at a time. That single difference changes everything: MJF wins on speed and surface quality, SLS wins on material choices and huge build sizes.

Quick Side-by-Side Table

Where Each One Wins

1. Detail & Accuracy

MJF edges are crisper. Detailing agent keeps things sharp. Whole-layer heating means almost no warping. SLS can get a little soft on corners because the laser spot isn’t tiny and heat builds up differently across the bed.

2. Materials

MJF = PA12 world, plus glass-filled and PP. That’s basically it right now. SLS = whatever nylon you can dream of, including flexible, super-tough, filled, certified aerospace grades, etc.

3. Strength

SLS usually edges out on true isotropy. Great when your part gets pulled in every direction. MJF is still really strong and dense. Most people never notice the tiny Z-axis difference on normal PA12 parts.

4. Size

Need something longer than 500 mm in one piece? SLS 3D model is your only choice. Need 200 decent-sized parts this week? MJF all the way.

5. Speed & Quantity

MJF is the production animal. Short cycles, quick cooling, pack the bed and go. SLS is the “I only need five weird parts in TPU” machine.

Surface Finish Out of the Printer

MJF: smooth, uniform, looks like a real product. SLS: feels like fine sandpaper, classic powder-bed texture. Both in the 3D printing factory can be dyed, tumbled, or vapor-smoothed to look awesome, but MJF starts way ahead.

When to Pick MJF

· You want smooth, good-looking parts straight away

· Tight tolerances and repeatability matter

· You’re doing 20–500 pieces

· Need watertight ducts or manifolds

· Lead time is killing you

When to Pick SLS

· You must have PA11, TPU, carbon-fiber, or some certified material

· Part is huge

· You need living hinges or super flexible behavior

· Strength has to be identical in every direction

· It’s just a handful of prototypes

Speed, surface and production runs is the essence of MJF. Material freedom, big parts and max isotropy are the parts of SLS.

Pick the one that fixes your actual headache, not the one that sounds cooler in a brochure.

FAQ

Q: Which is faster: MJF or SLS?

A: MJF is significantly faster thanks to full-layer infrared heating. SLS is slower due to point-by-point laser scanning and long cooling cycles. MJF is better for low-to-mid volume production.

Q: Which technology gives smoother surface finish: MJF or SLS?

A: MJF parts have naturally smoother surfaces and more uniform dark-gray appearance. SLS parts are grainier with a matte white, powder-textured finish.

Q: For large parts, should I choose MJF or SLS?

A: SLS offers much larger build volumes (commonly up to ~700 × 380 × 580 mm), making it ideal for oversized or long single parts. MJF is typically limited to ~380 × 284 × 380 mm.