PA6 is the toughest and most forgiving of the three materials here — and the one most affected by moisture. These are the questions that decide whether PA6 or PA66 is the right base resin.
PA6 (Nylon 6) is a semi-crystalline polyamide built from caprolactam. It is tougher and flows better than PA66 and costs less, at the price of a lower melting point (215–225°C) and higher moisture uptake — the usual choice for clips, housings, gears and cable protection.
PA6 runs 1.13–1.15 g/cm³ unfilled and about 1.36 g/cm³ with 30% glass fibre. Density climbs with filler loading, so mineral-filled grades can approach 1.5 g/cm³ — worth checking when parts are bought by weight.
PA6 melts at 215–225°C, about 40°C below PA66. Barrels run at 230–260°C, which means PA6 can be moulded on older machines and needs less heat history than PA66.
Unfilled PA6 gives 55–75°C HDT at 1.80 MPa; 30% glass fibre raises it to 190–200°C. For continuous service above 100°C, PA66 or a heat-stabilised PA6 grade is the safer choice.
PA6 absorbs 1.6–1.9% in 24 hours — the highest of the three materials here — and continues towards equilibrium over weeks. Parts grow and lose stiffness as they take up water, so moisture conditioning before assembly is standard practice for precision parts.
Unfilled PA6 shrinks 0.8–1.5%; glass fibre brings it down to 0.3–0.6%. Because PA6 crystallises quickly, mould temperature has a strong effect on the final shrinkage — hold the mould temperature stable rather than chasing the number with packing pressure.
Unfilled PA6 reaches 70–80 MPa; 30% glass fibre takes it to 160–185 MPa. Impact strength is PA6's real advantage: 4–6 kJ/m² notched dry, and impact-modified grades exceed 15 kJ/m².
Standard supply covers 15%, 20%, 30% and 40% glass fibre, plus flame-retardant, impact-modified, UV-stabilised, wear-resistant and conductive versions. Modifiers trade against each other — flame retardants and glass both reduce elongation, so specify the property that cannot fail first.
Yes, and halogen-free phosphorus/nitrogen systems are increasingly preferred for RoHS and REACH reasons. V-0 is achievable at 0.8–1.6 mm depending on the system; the flame package reduces toughness, so impact requirements should be stated up front.
Dry at 80–90°C for 4–6 hours with a dew point below −20°C. PA6 picks up moisture faster than PA66, so keep bags sealed, use a desiccant dryer and avoid leaving resin in an open hopper overnight.
Barrel 230–260°C with the nozzle about 10°C cooler, mould 60–90°C. Higher mould temperature improves crystallinity, surface finish and dimensional stability; too low a mould temperature produces flow marks and post-mould shrinkage.
Caprolactam pricing, glass or flame-retardant loading, colour, packaging and batch size. Unfilled natural resin sits at the bottom of the range; each modification step adds cost. Because PA6 base resin is cheaper than PA66, the modification package often dominates the final price — specify performance first, then compare.
Take PA66 when continuous service exceeds 100°C, when creep resistance matters, or when moisture-driven dimensional change is unacceptable. Take PA6 for toughness at ambient temperature, easier flow in thin walls and lower cost.
Cable protection and conduit, power-tool and appliance housings, gears, cable ties, textile machinery parts and general industrial components — parts that need toughness and fatigue resistance more than heat resistance.
Send the part, the service conditions and your monthly volume — we will propose an equivalent grade, a sample and a quote.