POM Delrin vs. PA6 Nylon: Which Engineering Plastic for Precision Gears and Bearings?
Published: 2026-06-04
POM (Delrin) and PA6 (Nylon 6) are the two most widely used unfilled engineering thermoplastics for mechanical components. The selection pivots on moisture: PA6 absorbs 2.5-3.0% moisture and loses ~30% tensile strength when humidity-equilibrated;...
POM (Delrin) and PA6 (Nylon 6) are the two most widely used unfilled engineering thermoplastics for mechanical components. The selection pivots on moisture: PA6 absorbs 2.5-3.0% moisture and loses ~30% tensile strength when humidity-equilibrated; POM absorbs <0.2% moisture and maintains stable dimensions. For precision gears requiring consistent tooth profile and backlash, POM is the default. For snap-fit connectors where impact resistance matters more than dimensional precision, PA6 wins on cost and toughness.
Comparison at a Glance
| Material A | POM Delrin (Polyoxymethylene) |
|---|---|
| Material B | PA6 Nylon 6 |
| Polymer Type | POM: Semi-crystalline | PA6: Semi-crystalline |
| Tensile Strength A | 70 MPa |
| Tensile Strength B | 80 MPa (dry) / 55 MPa (conditioned) |
| Cost Relative | POM 20-30% more expensive than PA6 |
| Best For A | Precision gears in dry environments, low friction |
| Best For B | Impact-resistant parts, snap-fits, cost-sensitive applications |
Frequently Asked Questions
Which material has better wear resistance for gear applications?
POM has significantly better wear resistance than PA6 in dry running conditions — its coefficient of friction (0.2-0.3 against steel) is ~40% lower than PA6 (0.35-0.45). POM gears last 3-5x longer in unlubricated applications. However, PA6 can be compounded with PTFE or MoS2 to narrow this gap at additional cost.
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org