Polyamide 6.6 (PA66 / Nylon 66) is a high-performance engineering thermoplastic known for its superior mechanical strength, stiffness, and dimensional stability compared to PA6. It is widely used in industrial applications requiring higher load capacity, improved creep resistance, and better thermal performance. PA66 is commonly supplied in rod and sheet forms for precision CNC machining of structural and load-bearing components.
What is Polyamide 6.6 (PA66 / Nylon 66)?
Polyamide 6.6 (PA66), also known as Nylon 66, is a high-performance engineering thermoplastic
characterized by higher stiffness, improved dimensional stability, and better creep resistance
when compared to standard PA6.
Due to its more crystalline molecular structure, PA66 maintains mechanical properties more consistently
under continuous load, elevated temperature, and demanding industrial conditions.
PA66 is widely used in mechanical engineering, industrial machinery, automotive components,
and precision CNC-machined parts where long-term stability and reliability are critical.
Key Engineering Characteristics of PA66
- High mechanical strength and stiffness: suitable for load-bearing and structural components.
- Excellent dimensional stability: reduced deformation under stress compared to PA6.
- Improved creep resistance: ideal for parts under constant or long-term load.
- Higher thermal resistance: performs better at elevated operating temperatures.
- Good wear resistance: suitable for sliding and rotating mechanical applications.
- Machinable engineering plastic: supplied in semi-finished forms for CNC machining.
Forms and Machining Options
Polyamide 6.6 is commonly supplied as:
- PA66 Rods for turned and rotational CNC parts
- PA66 Sheets for milled, flat, or structural components
Both forms are suitable for precision machining, provided that moisture conditioning
and tolerance requirements are properly considered.
Typical Industrial Applications
- Mechanical and structural machine parts
- Gears, bushings, bearings, and rollers
- Guides, sliders, wear components, and supports
- Automotive and industrial equipment parts
- CNC-machined components requiring higher stiffness than PA6
Typical Properties (Indicative)
| Property | Typical Range |
|---|---|
| Density | ~1.14 – 1.16 g/cm³ |
| Tensile Strength | ~75 – 100 MPa (grade-dependent) |
| Hardness | ~80 – 82 Shore D |
| Service Temperature | Approx. -30°C to +120°C |
| Creep Resistance | Higher than PA6 |
| Moisture Absorption | Lower than PA6 (design consideration required) |
PA66 vs PA6 – Category-Level Comparison
- PA66: higher stiffness, better dimensional stability, improved creep resistance
- PA6: tougher, more impact-resistant, easier machining, lower cost
PA66 is typically selected when mechanical rigidity, thermal performance,
and long-term dimensional accuracy are more important than toughness.
Selection Considerations
When choosing Polyamide 6.6 for an application, consider:
- Continuous vs intermittent load conditions
- Operating temperature and heat exposure
- Dimensional tolerance requirements
- Humidity and environmental exposure
- Machining method and final part geometry
FAQ
1) When should PA66 be chosen over PA6?
PA66 is preferred for applications requiring higher stiffness, better dimensional stability,
and improved creep resistance under continuous load.
2) Is PA66 suitable for CNC machining?
Yes. PA66 is commonly machined into precision industrial components from rod and sheet forms.
3) Does PA66 absorb moisture?
PA66 absorbs moisture less than PA6, but moisture effects should still be considered
for tight-tolerance applications.
For selecting the correct Polyamide 6.6 (PA66 / Nylon 66) form and grade,
consult with the technical team based on your load, temperature, and tolerance requirements.