Home · Materials · Nylon 66 (PA66)
Engineering Plastic

Nylon 66 (PA66)

Nylon 66 (PA66) is a tough, abrasion-resistant engineering thermoplastic with about 83 MPa tensile strength and good fatigue life. Compared with PA6, it has a higher melting point and greater stiffness and heat resistance, making it the default nylon for load-bearing wear parts where dimensional stability under heat matters.

How Nylon 66 (PA66) machines

Rated 3.5/5. It machines cleanly with sharp tools but, like most nylons, can absorb moisture and shift dimensions, and internal stresses may cause parts to move after cutting. Use sharp, polished tooling, allow for relaxation, and account for moisture conditioning when holding tight tolerances.

Manufacturing & processing

Primarily injection molded and extruded, with CNC from stock for low volumes and prototypes. Its higher melt point than PA6 demands hotter processing. It is hygroscopic: parts absorb water, which changes dimensions and properties, so drying before molding and conditioning after are standard.

Typical applications

Gears, bearings, bushings, cams, rollers, and wear pads exploit its toughness and low friction. Also used for fasteners, electrical insulators, and under-hood automotive components. Glass-filled grades extend it into stiff structural housings where unfilled PA66 lacks rigidity.

When to choose it

Choose PA66 over PA6 when you need higher heat resistance and stiffness in a wear part; choose it over POM when toughness and abrasion resistance outweigh POM's dimensional stability and lower moisture uptake. If parts must hold precise dimensions in humid service, POM or a glass-filled grade is safer.

Suitable surface finishes

Common finishes for Nylon 66 (PA66): bead blasting, powder coating. Use the finish selector →

FAQ

What is the difference between PA66 and PA6?
PA66 has a higher melting point and somewhat greater stiffness, hardness, and heat resistance, while PA6 is slightly tougher and easier to process. For gears and wear parts running warm, PA66 holds shape better; for impact-prone parts at lower temperature, PA6 can be the better pick.
Why does nylon absorb moisture, and does it matter?
Nylon is hygroscopic, taking up water from air. Absorbed moisture increases toughness and flexibility but lowers stiffness and swells the part, shifting dimensions. For precision components, condition parts to their service humidity and design clearances accordingly, or choose a less hygroscopic plastic like POM.
Should I use unfilled or glass-filled PA66 for gears?
Unfilled PA66 gives quiet, self-lubricating, impact-tolerant gears for moderate loads. Glass-filled PA66 roughly doubles tensile and stiffness for higher loads and heat but is more brittle and abrasive to mating parts. Match the fill to the load, speed, and noise requirements of the drive.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.