FabDigit

TPU vs PU Cast and 2 more: properties

TPUPU CastPU FoamPoron

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

0.03 GPa0 Msi
0 GPa2.9×10⁻⁴ Msi
2×10⁻⁴ GPa2.9×10⁻⁵ Msi
0 GPa2.18×10⁻⁴ Msi

Poisson's Ratio

0.48
0.49
0.3
0.3

Tensile Strength (Ultimate)

40 MPa5.8 ksi
12 MPa1.7 ksi
0.13 MPa0.02 ksi
1 MPa0.15 ksi

Elongation at Break

550%
700%
150%
150%

Hardness, Shore A

85 Shore A
40 Shore A
20 Shore A

Hardness, Shore D

33 Shore D
10 Shore D

Tear Strength

70 kN/m400 lbf/in
20 kN/m114 lbf/in
0.3 kN/m1.7 lbf/in
2 kN/m8.6 lbf/in

Compression Set (22 h, 70 °C)

35%
15%
5%
5%

Shear Modulus

7×10⁻⁴ GPa1.02×10⁻⁴ Msi

Bulk Modulus

2 GPa0.29 Msi

Compressive Strength

1 MPa0.15 ksi
0.01 MPa7.25×10⁻⁴ ksi
0.07 MPa0.01 ksi

Shear Strength

5 MPa0.73 ksi

Compressive Modulus

8×10⁻⁴ GPa1.16×10⁻⁴ Msi

Physical

Density and transition temperatures.

Density

1.18 g/cm³0.04 lb/in³
1.1 g/cm³0.04 lb/in³
0.03 g/cm³0 lb/in³
0.32 g/cm³0.01 lb/in³

Melting Temperature (Tm)

185°C365 °F

Glass Transition (Tg)

-40°C-40 °F
-50°C-58 °F
-50°C-58 °F
-35°C-31 °F

Water Absorption (24 h)

0.8%
0.5%
3%

Water Absorption (Saturation)

1.8%
1.5%
800%

Refractive Index

1.51
1.5

Thermal

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

Thermal Conductivity

0.2 W/m·K0.12 BTU/hr·ft·°F
0.18 W/m·K0.1 BTU/hr·ft·°F
0.04 W/m·K0.02 BTU/hr·ft·°F
0.06 W/m·K0.03 BTU/hr·ft·°F

Specific Heat Capacity

1,700 J/kg·K0.41 BTU/lb·°F
1,800 J/kg·K0.43 BTU/lb·°F
1,500 J/kg·K0.36 BTU/lb·°F
1,700 J/kg·K0.41 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

170 µm/m·K94.4 µin/in·°F
200 µm/m·K111 µin/in·°F
70 µm/m·K38.9 µin/in·°F

Max Service Temperature (continuous)

80°C176 °F
80°C176 °F
90°C194 °F
90°C194 °F

Vicat Softening Point (B50)

72°C162 °F

Limiting Oxygen Index

22%
21%
19%

Same in both: Min Service Temperature -40°C-40 °F · Max Service Temperature (short-term) 120°C248 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10⁹ Ω·m3.94×10¹⁶ µΩ·in
1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in

Dielectric Strength

25 kV/mm635 V/mil
20 kV/mm508 V/mil

Dielectric Constant (1 MHz)

5
5
1.1
1.7

Dissipation Factor (1 MHz)

0.05
0.05

Volume Resistivity

1×10¹¹ Ω·cm
1×10¹³ Ω·cm
1×10¹² Ω·cm
1×10¹³ Ω·cm

Surface Resistivity

1×10¹² Ω

Comparative Tracking Index (CTI)

600 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

78 / 100
78 / 100
70 / 100

UV / Weathering Resistance

40 / 100
35 / 100
25 / 100
40 / 100

Manufacturability

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

Machinability

25 / 100
25 / 100
90 / 100
80 / 100

Weldability

85 / 100
15 / 100
30 / 100

Formability (cold)

90 / 100
85 / 100
90 / 100
90 / 100

Polishability

40 / 100
25 / 100
5 / 100

Mold Shrinkage

1.2%
1.5%
1.5%

Melt Flow Rate

25 g/10 min

Processing Melt Temperature (typ.)

210°C410 °F
80°C176 °F

Mold Temperature (typ.)

30°C86 °F
100°C212 °F
50°C122 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

105 MJ/kg45,142 BTU/lb
102 MJ/kg43,852 BTU/lb
102 MJ/kg43,852 BTU/lb
100 MJ/kg42,992 BTU/lb

Embodied Carbon (primary production)

5.2 kg CO₂/kg
5 kg CO₂/kg
4.6 kg CO₂/kg
5 kg CO₂/kg

Embodied Water

250 L/kg30 gal/lb
210 L/kg25.2 gal/lb
220 L/kg26.4 gal/lb

Typical Recycled Content

2%
0%
10%
0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

34 kN·m/kg
11 kN·m/kg
4 kN·m/kg
3 kN·m/kg

Thermal Diffusivity

0.1 mm²/s
0.1 mm²/s
0.8 mm²/s
0.1 mm²/s

Same in both: Specific Stiffness (E / density) 0 MN·m/kg

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 scaleTPUPU CastPU FoamPoron

Manufacturing and finishing

CapabilityTPUPU CastPU FoamPoron
CNC machiningYes
Sheet metalYes
3D printingYes
Default conditionShore A 85Shore A 40Open CellStandard
Relative cost$$ Standard$$ Standard$ Budget$$ Standard
Min. machined wall0.5 mm
Best machined surfaceRa 0.8 µm
Conductive CoatingYes
Dyeing (Nylon)Yes
PaintingYes
Primer CoatingYes
Tinted CoatingYes
Vacuum MetallizationYes
Waterproof CoatingYes

Both are offered for Injection molding. They share 5 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Soft Touch Coating, Spray Painting, UV Coating.

Ready to make it?

Upload a CAD file and FabDigit prices the part in TPU and PU Cast 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.