When selecting materials for precision plastic components, engineers often debate between POM (Polyoxymethylene, aka Acetal) and Nylon (Polyamide). Both are excellent engineering thermoplastics, but their different properties make each suitable for specific applications. This comprehensive comparison will help you choose the right material for your project.
Understanding the Materials
POM (Acetal) Characteristics:
- High stiffness and dimensional stability
- Excellent fatigue resistance
- Low friction coefficient
- Good chemical resistance
- Low moisture absorption
Nylon Characteristics:
- High toughness and impact resistance
- Good abrasion resistance
- Higher moisture absorption
- Better temperature resistance
- More flexible than POM
Key Comparison Factors
| Property | POM | Nylon |
|---|---|---|
| Tensile Strength | 60-70 MPa | 45-90 MPa |
| Flexural Modulus | 2,800-3,200 MPa | 1,000-3,000 MPa |
| Moisture Absorption | 0.2-0.3% | 1.5-3.0% |
| Continuous Service Temp | 85°C | 120°C |
| Friction Coefficient | 0.1-0.3 | 0.2-0.4 |
When to Choose POM (Acetal)
POM excels in applications requiring:
- Precision parts needing dimensional stability (gears, bearings)
- Low friction applications (sliding components)
- Chemical resistance against solvents and fuels
- Dry environments where moisture absorption is a concern
- Parts needing excellent machinability
When to Choose Nylon
Nylon is preferable for:
- High impact and toughness requirements
- Wear-resistant applications (bushings, rollers)
- Higher temperature environments
- Parts needing some flexibility
- Applications where self-lubrication is beneficial
Cost Considerations
Generally, standard Nylon 6/6 is slightly more expensive than POM, but prices vary by:
- Reinforced grades (glass-filled, etc.)
- Special formulations (lubricated, etc.)
- Market fluctuations in raw materials
Common Applications
Typical POM Applications:
- Precision gears and gear wheels
- Lock components
- Medical devices
- Fuel system components
- Conveyor system parts
Typical Nylon Applications:
- Wear pads and sliding elements
- Cable ties and fasteners
- Power tool housings
- Automotive under-hood components
- Industrial rollers and wheels
Conclusion: How to Choose
The choice between POM and Nylon depends on your specific requirements:
- Choose POM for dimensional stability, low friction, and moisture resistance
- Choose Nylon for toughness, higher temperature resistance, and impact strength
For critical applications, consider prototyping with both materials or consulting with a material science specialist. CYLEX offer custom formulations that can enhance specific properties to meet your exact needs.
