Polyamide 6 and 66 (nylon)

PA66 (Pure Polyamide 66)

High strength and wear resistance; becomes very stiff with glass fiber. Absorbs moisture, and its properties change with moisture.

Processing temperatures

Melt (injection) temperature	280 °C
Mold surface temperature	85 °C
Ejection temperature	150 °C

Typical values. They vary (±) with grade and manufacturer; see the data sheet.

Physical properties (typical)

Density	1.14 g/cm³
Shrinkage (flow / cross)	1.5 / 1.5 %
Specific heat	1.65 kJ/kg·K
Thermal conductivity	0.24 W/m·K
Latent heat of crystallization (approx.)	102 kJ/kg

Drying

Drying is essential (about 80 °C, 4–6 hours; dry air).

For exact conditions see the material data sheet. Drying guide →

Points to watch

Moisture affects filling and strength (splay)
Dimensions change as the part reaches moisture equilibrium (swelling)
Warpage and surface quality in fiber-filled grades

Typical use: Gears, bearings, engine-bay parts, fasteners

Defects common with this material

Splay (silver streaks)

Fine silvery streaks on the part surface in the flow direction.

splay · silver streaks · moisture streaks

Brittleness / low impact strength

The part breaks more easily than expected; sometimes the surface looks fine.

brittleness · brittle part · cracking

Warpage

The part distorts or bends after it leaves the mold.

warpage · distortion · bowing

Sink mark

A dent on the surface opposite a thick section; the surface is drawn inwards.

sink mark · depression · sink

Dimensional variation and shrinkage differences

Part dimensions fall outside the tolerance or vary from cycle to cycle.

dimensional error · shrinkage · out of tolerance

Short shot (incomplete fill)

The cavity does not fill completely; the farthest or thinnest area of the part stays incomplete.

incomplete fill · underfill · non-fill

Other grades in the same family

Do the values for this material not match your grade? and we will correct them.