Is nylon suitable for 3D printing?

The short answer

Which nylon, for which process

Nylon is not one material. PA6, PA11 and PA12 behave differently, and the process changes the behaviour again. Powder-bed printing, meaning SLS and MJF, fuses unfilled PA12 into a part that is nearly isotropic because the polymer is not laid down in layers of melt. FDM printing extrudes a filament, so the part is strong in the print plane and weaker across the layer boundaries. That single difference decides more applications than the datasheet values do.

The properties that decide the application

These are the figures we check first when a customer asks whether nylon is suitable. They are typical published values for commercial powders and filaments, and every one of them shifts with grade, build orientation and moisture state.

Heat resistance, in real numbers

Heat is where nylon earns its place in engineering work and also where the trade-offs are clearest. Unfilled PA12 holds its shape to roughly 170 to 175 C under light load, PA6 goes higher, and PA11 is the low-temperature member of the family at about 90 to 100 C. Carbon or glass filling raises stiffness dramatically but adds very little to heat resistance, which is a common misunderstanding: a carbon-filled grade chosen for heat will disappoint, while the same grade chosen for stiffness and creep resistance will not.

Moisture is the number one cause of bad parts

Every nylon absorbs water from the air, and the consequences run in both directions. Wet filament prints badly: the absorbed water boils at the nozzle, producing a foamed, rough surface, micro-voids in the extrusion path and visibly weaker layer bonds. Wet parts also behave differently in service. A saturated PA6-CF part retains roughly 47 percent of its dry tensile strength, while a saturated PA612-CF part retains about 90 percent. Toughness can move the other way, because absorbed water plasticises the matrix and can nearly triple the notched impact of a glass-filled grade. The lesson is that the honest question is not which nylon, it is which environment.

Humidity also moves dimensions. A PA12 part exposed to 50 percent relative humidity for a day may grow by 0.1 to 0.2 percent, while a PA11 part can swell up to 0.4 percent. On a 200 mm part that is most of a tolerance band, so if the drawing calls for a tight fit, either account for the swell in the model or specify a sealing coat.

Where nylon is the right answer

• Snap fits, clips and latches. Nylon bends instead of shattering, which is why it replaced ABS in most repeated-assembly features.
• Gears, sliders and wear surfaces. Unlubricated sliding contact suits nylon well, and carbon-filled grades add the stiffness and creep resistance a load-bearing housing needs.
• Ducts, manifolds and fluid routing. Nylon has good resistance to oils, fuels and many solvents, provided the service temperature stays inside the grade's limit.
• Brackets, drone arms and structural prototypes. The strength-to-weight ratio is the best available in polymer powder-bed printing, and MJF packs parts densely enough to make short production runs economic.
• Living hinges and fatigue parts. Use PA11 here rather than PA12: a documented switch from PA12 to PA11 for an integral hinge took a part from cracking at 50 to 100 cycles to surviving over 5,000.

Where nylon is the wrong answer

• Prolonged ultraviolet exposure. Unprotected nylon fades and embrittles outdoors. Use ASA or a UV-stable material instead, or accept a coating and a shorter service life.
• Continuous service above the grade limit. Above roughly 120 C, unfilled PA12 creeps under load. That is a design constraint, not a printing parameter.
• Strong acids and oxidising agents. Nylon resists fuels and oils, not everything.
• Precision bearing fits and sealing faces. Powder-bed as-cast tolerance is about plus or minus 0.3 mm. Plan a machined bore rather than specifying a tolerance the process cannot hold.
• Cosmetic surfaces and food contact. Powder-bed parts have a uniform matte grain, and printed porosity makes them unsuitable for repeated food contact without a compliant seal.
• Very thin cosmetic walls. MJF needs about 0.8 to 1.0 mm minimum wall, with 0.5 mm as the fine-detail limit and 1.0 mm minimum hole diameter to avoid powder entrapment.

Specifying nylon with us

If you send the model, the load case, the service temperature and the environment, we will tell you whether nylon is the right call and which grade, then return a price for powder-bed or filament production with the drying and annealing steps included rather than charged as extras. Where an as-cast feature cannot hold your tolerance we will say so at DFM review and quote the machining. See SLS nylon 3D printing, FDM 3D printing and SLM metal 3D printing if the temperature limit rules polymer out.