Question 1

What is MJF 3D printing?

Accepted Answer

MJF (Multi Jet Fusion), an HP powder-bed process, jets a binding agent onto nylon powder and fuses it with heat, layer by layer. The unfused powder supports the part, so it needs no supports and prints strong, near-isotropic parts with consistent mechanical properties.

Question 2

MJF vs SLS: what is the difference?

Accepted Answer

Both fuse nylon powder with no supports and give strong, near-isotropic parts. MJF uses a printed agent plus heat instead of a laser, which tends to give finer detail, more consistent part-to-part properties, and faster full-bed throughput. SLS offers a slightly wider material range on some machines. For most nylon parts they are close substitutes.

Question 3

What materials does MJF use?

Accepted Answer

The most common is PA12 (nylon 12), plus PA11 for more ductility and impact resistance, glass-filled nylon (PA12-GF) for stiffness and heat resistance, and TPU for flexible parts. MJF PA12 parts come off the machine grey and are usually dyed black for a uniform finish.

Question 4

What tolerance can MJF hold?

Accepted Answer

Typical MJF tolerance is about +/- 0.3% of the dimension, with a minimum near +/- 0.3 mm, and it is very consistent from part to part. Call out critical features so the shop can confirm feasibility and orientation.

Question 5

Does MJF need support structures?

Accepted Answer

No. Like SLS, the surrounding powder bed supports the part during the build, so there are no supports to remove and no support marks. That lets MJF print lattices, enclosed features, and interlocking assemblies, and nest parts densely for efficient batches.

Design rule	Typical spec	Why
Typical tolerance	+/- 0.3% (min +/- 0.3 mm)	Consistent part to part across a build.
Min wall thickness	0.5 to 0.8 mm	Thinner walls can warp or fuse incompletely.
Min feature size	0.4 mm	Slightly finer than SLS thanks to the printed agent.
Support material	none needed	The powder bed supports the part, so there are no supports to remove.
Clearance for moving parts	0.4 to 0.5 mm	Tighter gaps fuse mating parts together.
Escape holes (hollow parts)	>= 4 mm, two holes	Let trapped powder drain out of enclosed volumes.

Process	Best for	Typical volume	Choose it over MJF 3D Printing when
SLS	Similar strong nylon parts	Low-volume production	Your shop runs SLS, or you want a specific SLS material; the two are close substitutes.
FDM / FFF	Cheap prototypes, large parts	Prototype to low volume	You want the lowest cost or a large part and can accept layer lines.
Resin / SLA	Fine detail, smooth cosmetic finish	Prototype	You need the crispest detail or a smooth cosmetic surface over nylon toughness.
Injection Molding	High-volume identical plastic parts	1,000+	You are past a few hundred parts and can amortize a mold for lower per-part cost.

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