Material Specifications - Acetal (Polyoxymethylene)

Material Specifications
Acetal (Polyoxymethylene), Unreinforced


Acetal is a hard engineering plastic with high tensile strength and rigidity, excellent machining ability and versatility of application. Acetal has creep resistance and is resistant to hydrolysis, strong alkalis and thermo oxidative degradation. Acetal is suitable for use in components where exceptional strength is needed for above average temperature or moisture levels.


High-performance engineering components such as small gear wheels, eyeglass frames, ball bearings, ski bindings, fasteners, guns, knife handles, and lock systems.

Technical Specifications

The guaranteed minimum mechanical properties of Acetal (Polyoxymethylene), Unreinforced are shown below.

Physical Properties Metric
Density 1.41 g/cc
Water Absorption 0.552 %
Moisture Absorption at Equilibrium 0.234 %
Water Absorption at Saturation 1.16 %
Linear Mold Shrinkage 0.0204 cm/cm
Melt Flow 15.8 g/10 min
Mechanical Properties Metric
Hardness, Rockwell M 81.2
Hardness, Rockwell R 100
Hardness, Shore D 80.7
Ball Indentation Hardness 135 MPa
Tensile Strength, Ultimate 56.1 MPa
Tensile Strength, Yield 59.3 MPa
Elongation at Break 36.7%
Modulus of Elasticity  2.82 GPa
Compressive Yield Strength 60.1 MPa
Poissons Ratio 0.363
Fatigue Strength 68.9 MPa
Shear Strength 52 MPa
Tensile Impact Strength 167 kJ/m²
Coefficient of Friction 0.220
Electrical Properties Metric
Electrical Resistivity 2.42e+15 ohm-cm
Dielectric Constant 3.85
Arc Resistance 115 sec
Hot Wire Ignition, HWI 9.13 sec
High Amp Arc Ignition, HAI 120 arcs
Thermal Properties Metric
CTE, linear 104 µm/m-°C
Specific Heat Capacity 1.48 J/g-°C
Thermal Conductivity  0.292 W/m-K
Melting Point 160 - 186 °C
Minimum Service Temperature, Air -40 °C
Flammability, UL94 HB - V-2
Processing Properties Metric
Processing Temperature 199 °C
Melt Temperature 194 °C
Moisture Content 0.132 %
Injection Pressure 71.8 MPa