Nylon vs Delrin (POM) for CNC Parts: Which Plastic to Choose?

Delrin excels in dimensional stability and low friction for precision parts like gears and bearings. Nylon offers better impact resistance and higher temperature performance but absorbs more moisture, causing dimensional changes.

Side-by-Side Property Comparison

PropertyNylon 66 (PA66)Delrin (POM / Acetal)
Tensile Strength82 MPa (11.9 ksi)70 MPa (10.2 ksi)
Yield Strength69 MPa (10 ksi)65 MPa (9.4 ksi)
HardnessRockwell R120Rockwell M80
Density1.14 g/cm³1.42 g/cm³
Machinability Rating68/10085/100
Thermal Conductivity0.26 W/m·K0.31 W/m·K
Melting Point262 °C175 °C
Tolerance±0.05 mm±0.02 mm

Key Differences

PropertyNylon 66 (PA66)Delrin (POM / Acetal)Winner
Dimensional StabilityFair (moisture)ExcellentDelrin
Moisture Absorption2.5%0.25%Delrin
Impact ResistanceExcellentGoodNylon
Friction Coefficient0.30-0.400.20-0.35Delrin
Temperature RangeUp to 120°CUp to 100°CNylon
Machinability68/10085/100Delrin

Which Material Should You Choose?

Choose Nylon 66 (PA66) when:

  • Impact-loaded components
  • Higher temperature applications (up to 120°C)
  • Parts needing better chemical resistance
  • Under-hood automotive components
  • Structural parts requiring toughness
View Details Nylon 66 (PA66)

Choose Delrin (POM / Acetal) when:

  • Precision gears and bearings
  • Parts with tight tolerances
  • Low-friction sliding surfaces
  • Humid or wet environments
  • Food processing equipment
View Details Delrin (POM / Acetal)

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