Nylon’s combination of toughness, fatigue resistance, and self-lubricating properties makes it the right material for gears, hinges, living hinges, snap fits, and load-bearing functional parts. It absorbs impacts without cracking, flexes repeatedly without fatiguing, and wears well against other surfaces. The tradeoff: it’s the most moisture-sensitive common filament and requires more setup than any other consumer material.
Where Nylon Makes Sense
Gears and pulleys in light machinery. Snap-fit parts that need to open and close hundreds of times. Tool handles, structural brackets with repeated dynamic loads. Parts that will be in contact with moving surfaces (nylon’s self-lubricating property). Anything that must survive drop impacts or shock loads without shattering.
PA6 (common “Nylon 6”) is a general-purpose grade. PA12 is more dimensionally stable and absorbs less moisture — better for precision parts. PA6-CF and PA12-CF add carbon fiber for stiffness without losing toughness significantly.
Where Nylon Underperforms
Outdoor UV exposure — unmodified nylon degrades with UV radiation. Use ASA for outdoor applications. High-humidity environments where parts will absorb water during use — nylon continues to absorb moisture in service, which changes its dimensions and mechanical properties. Anywhere the dimensional change from moisture absorption is unacceptable (bearings, press-fit connections).
Moisture: The Critical Issue
Nylon absorbs moisture faster than any other common filament. New factory-sealed spools are dry. After 2–4 hours in a humid room, they’re wet enough to show print quality problems. After 24 hours open, print quality deteriorates significantly.
Dry before printing: 70–80°C for 8–12 hours. Not optional. Wet nylon produces weak, rough prints with poor layer adhesion. A food dehydrator at 75°C is reliable; most kitchen ovens cannot hold temperature accurately enough.
Use a dry box during printing: A sealed container with desiccant feeding filament directly to the printer. Without a dry box, a full spool can absorb enough moisture mid-print to show degradation before the print finishes.
Temperature
Nozzle: 250–260°C for PA6. PA12 often prints at 245–255°C. High-temperature variants (PA6-GF, PA6-HT) may need 270–280°C. Start at 255°C and adjust based on layer adhesion and surface quality.
Bed: 70–90°C. The bed surface matters as much as the temperature. PEI gives poor adhesion — nylon doesn’t bond well to it. Use a PVA glue stick on PEI or glass, or use a Garolite/G10 bed surface specifically designed for nylon. Without a proper release agent or surface, nylon either won’t stick or sticks too aggressively and deforms on removal.
Enclosure
Required. Nylon’s moisture absorption accelerates in open environments, and the enclosure also maintains thermal consistency to prevent delamination. A chamber temperature of 40–50°C is the target.
Fan
Minimal cooling — 0–20% fan speed. Nylon needs inter-layer heat retention for bonding. Full fan causes significant layer adhesion failure.
Post-Print Dimension Change
Nylon parts absorb moisture from the air during use and change dimensions — typically expanding 0.1–0.5% depending on geometry and humidity. If designing press-fit or bearing parts in nylon, print slightly undersized and allow the part to equalize to ambient humidity before fitting. Design for the wet dimension, not the dry-off-the-printer dimension.