Materials / Compare

Plastic Nylon PA66 vs. Plastic POM/Acetal

Compare Plastic Nylon PA66 vs. Plastic POM/Acetal strength, stiffness, weight and thermal properties.

Change either side
Plastic Nylon PA66Bulk polymer (molded or machined)
Plastic POM/AcetalBulk polymer (molded or machined)
Try it on a partA bracket to run stress or thermal on, free in your browserOpen in LessCADOpen in LessCAD
Mechanical
Yield strength85MPasourcetypical, dry69MPasourcetypical (single ASTM D638 tensile strength)
Ultimate tensile strengthnot sourced69MPasourcetypical
Compressive strengthnot sourced124MPasourcecompressive stress at 10% deformation
Flexural strengthnot sourced99MPasourceflexural yield strength, typical
Elongation at break30%sourcenominal strain at break, dry75%sourcetypical
Young's modulus (stiffness)3GPasourcetypical, dry2.8GPasourcetypical
Density1,130kg/m³sourcetypical1,420kg/m³sourcetypical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties')
Strength to weight75.2kN·m/kg1.55x higher48.6kN·m/kg
Stiffness to weight2.65MN·m/kg35% higher1.97MN·m/kg
Poisson's ratio0.4sourcebase material: unfilled polyamide (PA), conditioned, maker design-guide family value (Covestro Table 3-1)0.35sourcetypical
Shear modulus1.07GPa3% stiffer in shear1.04GPa
Bulk modulus5GPa3.11GPa
Speed of sound1,629m/s1,404m/s
Thermal
Thermal conductivity0.33W/m·Ksourcetypical0.4W/m·Ksourcetypical21% more heat through a fin
Thermal expansion98µm/m·Ksourcelongitudinal, 23-55 °C122µm/m·Ksourcemean, 29 to 60 °C
100 mm part over a 50 °C swing490µm growth24% less610µm growth
Specific heat1,700J/kg·Ksourcetypical1,465J/kg·Ksourceaverage -18 to 100 °C, Delrin acetal resins (not grade-specific)
Heats up and cools (diffusivity)0.172mm²/s0.192mm²/s12% faster
Thermal shock resistance57.2W/m9% more resistant52.5W/m
Melting point260°CsourceDSC175°Csourcecrystalline melting point
Max service temperature101°CsourceIEC 60216 temperature index, 20000 h125°CsourceHDT 1.8 MPa (annealed)
Values forBASF Ultramid A3K (PA66, unreinforced injection-moulding grade), Product Information 02/2026, dry values (ISO methods)DuPont Delrin 100 acetal homopolymer, Table 2 'Typical Properties of Delrin Acetal Resins' (ASTM methods), Delrin Design Guide Module III hosted on delrin.com

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is Plastic Nylon PA66 stronger than Plastic POM/Acetal?

Plastic Nylon PA66 is stronger: its yield strength is 85 MPa against 69 MPa for Plastic POM/Acetal (23%).

Which is lighter, Plastic Nylon PA66 or Plastic POM/Acetal?

Plastic Nylon PA66 is lighter: 1,130 kg/m³ against 1,420 kg/m³ for Plastic POM/Acetal.

Which is stiffer, Plastic Nylon PA66 or Plastic POM/Acetal?

Plastic Nylon PA66 is stiffer: Young's modulus 3 GPa against 2.8 GPa for Plastic POM/Acetal, so the same part in Plastic Nylon PA66 deflects less under the same load.

Which is lighter for the same job, Plastic Nylon PA66 or Plastic POM/Acetal?

For the same stiffness or strength: Plastic Nylon PA66 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must bePlastic Nylon PA66Plastic POM/Acetal
Stiff rod or tie (tension)lighter35% heavier
Stiff beam (bending)lighter30% heavier
Stiff panel or platelighter29% heavier
Strong rod or tielighter1.55x heavier
Strong beamlighter44% heavier
Strong panel or platelighter39% heavier

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which conducts heat better, Plastic Nylon PA66 or Plastic POM/Acetal?

Plastic POM/Acetal conducts heat better: 0.4 W/m·K against 0.33 W/m·K for Plastic Nylon PA66.

Which expands less with temperature?

Plastic Nylon PA66 expands less: 98 µm/m·K against 122 µm/m·K for Plastic POM/Acetal.

Among 59 materials

1k10k0.1110100Density (kg/m³)Young's modulus (GPa)Plastic PLAPlastic PETGPlastic ABSPlastic TPUPlastic NylonAluminumSteelIronTitaniumSteel AISI 1018Stainless 304Stainless 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless 303Stainless 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic Nylon PA6Plastic PEEKPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin Tough 2000SLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelPlastic Nylon PA66Plastic POM/Acetal
Stiffness against density
1k10k101001kDensity (kg/m³)Yield strength (MPa)Plastic PLAPlastic PETGPlastic ABSPlastic TPUPlastic NylonRubberAluminumSteelIronTitaniumSteel AISI 1018Stainless 304Stainless 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless 303Stainless 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic Nylon PA6Plastic PEEKPlastic PTFEPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin Tough 2000SLA Resin Elastic 50ASLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelBrickPlastic Nylon PA66Plastic POM/Acetal
Strength against density

Related comparisons