Differences between PA6 and PA66 in industrial applications

Comparing the key properties of PA6 and PA66

1) Heat resistance

In general, PA66 offers higher heat resistance than PA6 and maintains its shape and strength better at elevated service temperatures.
For equipment where parts are exposed to high temperatures on a continuous basis, PA66 is usually the safer choice to minimise deformation and loss of performance.

2) Mechanical strength and hardness

Both polyamide grades provide high mechanical strength; however, PA66 is typically one step higher in terms of hardness and load-bearing capacity.
This advantage is especially important in components such as gears, bushings and bearings that operate under constant or impact loads, helping to extend service life and reduce wear.
By contrast, PA6 is slightly softer and more flexible, and in applications where occasional shocks occur it can show more forgiving behaviour.

3) Moisture absorption and dimensional stability

One of the common challenges with polyamides is moisture uptake.
PA6 absorbs more moisture than PA66, which can lead to dimensional changes over time.
PA66, on the other hand, offers better dimensional stability and is therefore more suitable for precision CNC parts where tight tolerances must be maintained throughout the service life.

4) Machinability (CNC)

Both grades can be machined and turned on CNC equipment.
Because it is somewhat softer, PA6 is easier to machine and puts less load on the cutting tools.
PA66, due to its higher hardness, is more demanding to machine, but when tooling and cutting conditions are properly optimised, it yields parts that are harder and more dimensionally stable in operation.

Typical industrial applications of PA6 and PA66

The choice between PA6 and PA66 depends on the service conditions, type of loading and operating temperature. Typical use cases include:

Applications suited to PA6

• Gears and motion-transfer components under medium loads
• Bushings and sliding supports where some flexibility is beneficial
• Parts where fast, economical machining is a priority

Applications suited to PA66

• High-speed industrial gears operating under heavy loads
• Bearings, bushings and components exposed to higher temperatures
• Precision parts where dimensional stability and high strength are critical

Summary: which polyamide is the better fit?

If your design requires higher temperature resistance, greater stiffness and superior mechanical strength,
choosing PA66 is usually the more robust option. If, instead, easier machining, higher flexibility and lower overall part cost are more important for your project,
PA6 will often be the more suitable choice.

Selecting the right grade between these two can extend the service life of your polyamide components,
help prevent unplanned production downtime and reduce maintenance costs over the long term.