Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide

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Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide
Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide
Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide
Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide
Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide
Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide
Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide

Chemical Structure Differences

The fundamental difference between PA6 (Nylon 6) and PA66 (Nylon 66) lies in their molecular structure:

  • Nylon 6: Made from caprolactam, has 6 carbon atoms in each repeating unit. Less crystalline structure.
  • Nylon 66: Made from hexamethylenediamine and adipic acid, has two 6-carbon chains. More crystalline structure.

Mechanical Properties Comparison

Property PA6 PA66
Tensile Strength 70-85 MPa 80-100 MPa
Flexural Modulus 2.5-3.0 GPa 2.8-3.5 GPa
Elongation at Break 30-100% 15-60%
Notched Izod Impact 50-100 J/m 40-80 J/m
Melting Point 220°C 260°C
HDT at 1.8 MPa 70°C 90°C

Moisture Absorption

Moisture absorption is critical for nylon applications:

Condition PA6 PA66
At 50% RH 2.5-3.0% 2.0-2.5%
Saturation 8-10% 6-8%

Processing Characteristics

Nylon 6 Processing

  • Melting Point: 220°C
  • Processing Range: 240-280°C
  • Mold Temperature: 40-80°C

Nylon 66 Processing

  • Melting Point: 260°C
  • Processing Range: 280-320°C
  • Mold Temperature: 60-90°C

Applications by Material

Nylon 6 Applications

  • Gears and sprockets
  • Industrial monofilament
  • Film and packaging
  • Consumer products

Nylon 66 Applications

  • Automotive under-hood components
  • Electrical connectors
  • High-temperature bearings
  • Precision mechanical components

Reinforced Grades

Both materials are commonly reinforced with glass fiber:

Grade PA6 + GF30 PA66 + GF30
Tensile Strength 140-160 MPa 170-200 MPa
HDT (1.8 MPa) 205°C+ 250°C+
Moisture Absorption 1.0-1.5% 0.8-1.2%

Selection Summary

Choose Nylon 6 when:

  • Impact resistance is critical
  • Cost sensitivity is high
  • Operating temperatures are moderate

Choose Nylon 66 when:

  • Higher mechanical strength is required
  • Elevated temperatures are expected
  • Dimensional stability is critical

FAQ

When is Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide a good option?

Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide is a good option when fast iteration, complex geometry, low tooling cost, or low-volume production is more important than molded-part unit cost.

What should be checked before choosing Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide?

Check part size, material properties, surface finish, dimensional tolerance, heat exposure, load direction, and whether post-processing is required.

How does Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide compare with CNC machining?

3D printing can create complex shapes quickly, while CNC machining is often stronger for precise surfaces, tighter tolerances, and production-grade materials.

What affects the cost of Nylon 6 vs Nylon 66 — Engineering Plastic Selection Guide?

Cost depends on material, build volume, print time, layer height, support removal, finishing, inspection, and the number of parts in the build.

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