EPP Foam vs PU Foam
Polymer · grade comparison
EPP Foam and PU Foam are both polymer grades. EPP Foam is the stronger of the two: tensile strength 0.5 MPa (0.0725 ksi) against 0.13 MPa (0.0189 ksi) for PU Foam, about 3.8 times as much. In exchange, PU Foam is the more ductile: elongation 150% versus 15% for EPP Foam. PU Foam is lighter (0.03 g/cm³ vs 0.05 g/cm³ for EPP Foam) and EPP Foam is stiffer (0.01 GPa vs 2×10⁻⁴ GPa). On the shop floor, PU Foam machines more easily (excellent vs good), EPP Foam welds better (fair vs poor), and PU Foam sits in a lower cost tier (budget, $) than EPP Foam (standard, $$).
EPP FoamChoose it when strength drives the design, or when the part sees heat.
PU FoamChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
EPP Foam vs 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Tear Strength
Compression Set (22 h, 70 °C)
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
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)
Limiting Oxygen Index
Same in both: Min Service Temperature -40°C-40 °F · Max Service Temperature (short-term) 120°C248 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Constant (1 MHz)
Volume Resistivity
Surface Resistivity
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)
Mold Shrinkage
Mold Temperature (typ.)
Same in both: Polishability 5 / 100
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
Same in both: 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.
Manufacturing and finishing
| Capability | EPP Foam | PU Foam |
|---|---|---|
| Default condition | Closed Cell | Open Cell |
| Relative cost | $$ Standard | $ Budget |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both are offered for Injection molding. Both take the same 5 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Soft Touch Coating, Spray Painting, UV Coating.
EPP Foam vs PU Foam — frequently asked
Is EPP Foam stronger than PU Foam?
Yes. EPP Foam has a typical tensile strength of 0.5 MPa (0.0725 ksi) against 0.13 MPa (0.0189 ksi) for PU Foam — about 3.8 times as much.
Which is cheaper, EPP Foam or PU Foam?
PU Foam is the lower-cost material: it sits in the budget tier ($) while EPP Foam is standard ($$). 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, EPP Foam or PU Foam?
PU Foam. Its machinability rates excellent (90/100) against good (60/100) for EPP Foam; for welding the order is EPP Foam first (fair, 45/100) then PU Foam (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in EPP Foam and 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.