PEEK vs Delrin (POM): Engineering Plastics Comparison for CNC

Delrin is the cost-effective workhorse for precision mechanical parts with low friction. PEEK is the premium choice for extreme temperatures, chemical resistance, and aerospace/medical applications where its 10x higher cost is justified.

Side-by-Side Property Comparison

PropertyPEEK (Polyether Ether Ketone)Delrin (POM / Acetal)
Tensile Strength100 MPa (14.5 ksi)70 MPa (10.2 ksi)
Yield Strength91 MPa (13.2 ksi)65 MPa (9.4 ksi)
HardnessRockwell M99Rockwell M80
Density1.31 g/cm³1.42 g/cm³
Machinability Rating60/10085/100
Thermal Conductivity0.25 W/m·K0.31 W/m·K
Melting Point343 °C175 °C
Tolerance±0.02 mm±0.02 mm

Key Differences

PropertyPEEK (Polyether Ether Ketone)Delrin (POM / Acetal)Winner
Max Temperature260°C continuous100°C continuousPEEK
Tensile Strength100 MPa70 MPaPEEK
Machinability60/10085/100Delrin
Cost~$100+/kg~$5-10/kgDelrin
Chemical ResistanceExceptionalGoodPEEK
Dimensional StabilityGoodExcellentDelrin

Which Material Should You Choose?

Choose PEEK (Polyether Ether Ketone) when:

  • High-temperature environments (>100°C)
  • Aggressive chemical exposure
  • Medical implants (biocompatible)
  • Aerospace structural parts
  • Semiconductor cleanroom applications
View Details PEEK (Polyether Ether Ketone)

Choose Delrin (POM / Acetal) when:

  • Gears, bearings, and bushings
  • Food processing components
  • Cost-sensitive projects
  • Precision mechanical parts
  • General engineering applications
View Details Delrin (POM / Acetal)

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