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PAR vs POM

Polymer · grade comparison

PAR and POM are both polymer grades. PAR is the stronger of the two: yield strength 68 MPa (9.86 ksi) against 62 MPa (8.99 ksi) for POM, about 10% more; tensile strength follows at 72 MPa (10.4 ksi) vs 63 MPa (9.14 ksi). PAR is the more ductile: elongation 60% versus 30% for POM. PAR is lighter (1.21 g/cm³ vs 1.41 g/cm³ for POM) and POM is stiffer (2.8 GPa vs 2.1 GPa). On the shop floor, POM machines more easily (excellent vs good) and POM sits in a lower cost tier (standard, $$) than PAR (high, $$$$).

PARChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

POMChoose it when the part is machined in volume, or when cost is the deciding factor.

PAR vs POM: properties

PARPOM

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

2.1 GPa0.3 Msi
2.8 GPa0.41 Msi

Shear Modulus

0.75 GPa0.11 Msi
1.1 GPa0.15 Msi

Bulk Modulus

4 GPa0.51 Msi
3 GPa0.45 Msi

Poisson's Ratio

0.4
0.35

Tensile Strength (Ultimate)

72 MPa10.4 ksi
63 MPa9.1 ksi

Yield Strength (0.2% offset)

68 MPa9.9 ksi
62 MPa9 ksi

Elongation at Break

60%
30%

Compressive Strength

85 MPa12.3 ksi
105 MPa15.2 ksi

Compressive Modulus

2.2 GPa0.32 Msi
2.7 GPa0.39 Msi

Flexural Modulus

2.1 GPa0.3 Msi
2.6 GPa0.38 Msi

Shear Strength

58 MPa8.4 ksi
55 MPa8 ksi

Izod Impact, Notched

230 J/m4.3 ft·lbf/in
70 J/m1.3 ft·lbf/in

Hardness, Shore D

85 Shore D
81 Shore D

Hardness, Rockwell M

88 HRM
80 HRM

Hardness, Rockwell R

125 HRR
120 HRR

Fracture Toughness (K_IC)

—
4 MPa·√m3.6 ksi·√in

Same in both: Flexural Strength 90 MPa13.1 ksi

Physical

Density and transition temperatures.

Density

1.21 g/cm³0.04 lb/in³
1.41 g/cm³0.05 lb/in³

Glass Transition (Tg)

190°C374 °F
-60°C-76 °F

Water Absorption (24 h)

0.26%
0.22%

Refractive Index

1.61
—

Light Transmission

86%
—

Melting Temperature (Tm)

—
166°C331 °F

Same in both: Water Absorption (Saturation) 0.8%

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.18 W/m·K0.1 BTU/hr·ft·°F
0.31 W/m·K0.18 BTU/hr·ft·°F

Specific Heat Capacity

1,200 J/kg·K0.29 BTU/lb·°F
1,470 J/kg·K0.35 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

62 µm/m·K34.4 µin/in·°F
110 µm/m·K61.1 µin/in·°F

Max Service Temperature (continuous)

150°C302 °F
95°C203 °F

Min Service Temperature

-50°C-58 °F
-40°C-40 °F

Heat Deflection Temp. @ 0.45 MPa

185°C365 °F
158°C316 °F

Heat Deflection Temp. @ 1.8 MPa

174°C345 °F
104°C219 °F

Vicat Softening Point (B50)

187°C369 °F
160°C320 °F

Limiting Oxygen Index

34%
15%

Max Service Temperature (short-term)

180°C356 °F
140°C284 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁴ Ω·m3.94×10²¹ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Dielectric Constant (1 MHz)

3
3.7

Dissipation Factor (1 MHz)

0.012
0.005

Volume Resistivity

1×10¹⁶ Ω·cm
1×10¹⁴ Ω·cm

Surface Resistivity

1×10¹⁵ Ω
1×10¹⁴ Ω

Comparative Tracking Index (CTI)

200 V
600 V

Same in both: Dielectric Strength 20 kV/mm508 V/mil

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
70 / 100

UV / Weathering Resistance

90 / 100
30 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

58 / 100
88 / 100

Weldability

60 / 100
55 / 100

Formability (cold)

55 / 100
40 / 100

Polishability

75 / 100
70 / 100

Mold Shrinkage

0.8%
2%

Processing Melt Temperature (typ.)

340°C644 °F
200°C392 °F

Mold Temperature (typ.)

130°C266 °F
85°C185 °F

Melt Flow Rate

—
9 g/10 min

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

145 MJ/kg62,339 BTU/lb
100 MJ/kg42,992 BTU/lb

Embodied Carbon (primary production)

7.5 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

350 L/kg41.9 gal/lb
200 L/kg24 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

60 kN·m/kg
45 kN·m/kg

Specific Stiffness (E / density)

1.7 MN·m/kg
2 MN·m/kg

Modulus of Resilience

1,101 kJ/m³
686 kJ/m³

Same in both: Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 0

Strength versus weight

Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scalePARPOM

Manufacturing and finishing

CapabilityPARPOM
Injection molding—Yes
Default condition—Unfilled
Relative cost$$$$ High$$ Standard
Min. machined wall——
Best machined surface——
Chrome Plating (Plastic)—Yes
EMI Shielding Coating—Yes
Soft Touch Coating—Yes
Spray Painting—Yes
UV Coating—Yes

PAR vs POM — frequently asked

Is PAR stronger than POM?

Yes. PAR has a typical yield strength of 68 MPa (9.86 ksi) against 62 MPa (8.99 ksi) for POM — about 10% more. Tensile strength is 72 MPa (10.4 ksi) vs 63 MPa (9.14 ksi).

Which is cheaper, PAR or POM?

POM is the lower-cost material: it sits in the standard tier ($$) while PAR is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, PAR or POM?

POM. Its machinability rates excellent (88/100) against good (58/100) for PAR; for welding the order is PAR first (good, 60/100) then POM (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in PAR and POM side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.