RIM PU Foam vs Viscoelastic PU Foam
Polymer · grade comparison
RIM PU Foam and Viscoelastic PU Foam are both polymer grades. RIM PU Foam is the stronger of the two: tensile strength 12 MPa (1.74 ksi) against 0.1 MPa (0.0145 ksi) for Viscoelastic PU Foam, about 120 times as much. In exchange, Viscoelastic PU Foam is the more ductile: elongation 150% versus 130% for RIM PU Foam. Viscoelastic PU Foam is lighter (0.05 g/cm³ vs 0.6 g/cm³ for RIM PU Foam) and RIM PU Foam is stiffer (0.22 GPa vs 2.5×10⁻⁴ GPa). On the shop floor, Viscoelastic PU Foam welds better (poor vs not recommended) and RIM PU Foam sits in a lower cost tier (standard, $$) than Viscoelastic PU Foam (premium, $$$).
RIM PU FoamChoose it when strength drives the design, or when cost is the deciding factor.
Viscoelastic PU FoamChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
RIM PU Foam vs Viscoelastic PU Foam: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
RIM PU FoamViscoelastic PU Foam
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Izod Impact, Notched
Hardness, Shore A
Hardness, Shore D
Tear Strength
Compression Set (22 h, 70 °C)
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Surface Resistivity
Comparative Tracking Index (CTI)
Same in both: Electrical Resistivity 1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in · Volume Resistivity 1×10¹² Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
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.
Manufacturing and finishing
| Capability | RIM PU Foam | Viscoelastic PU Foam |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
RIM PU Foam vs Viscoelastic PU Foam — frequently asked
Is RIM PU Foam stronger than Viscoelastic PU Foam?
Yes. RIM PU Foam has a typical tensile strength of 12 MPa (1.74 ksi) against 0.1 MPa (0.0145 ksi) for Viscoelastic PU Foam — about 120 times as much.
Which is cheaper, RIM PU Foam or Viscoelastic PU Foam?
RIM PU Foam is the lower-cost material: it sits in the standard tier ($$) while Viscoelastic PU Foam is premium ($$$). 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, RIM PU Foam or Viscoelastic PU Foam?
Viscoelastic PU Foam, by a small margin. Both rate good for machinability — 60/100 against 55/100 for RIM PU Foam; for welding the order is Viscoelastic PU Foam first (poor, 30/100) then RIM PU Foam (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in RIM PU Foam and Viscoelastic PU Foam 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.