JIS A9511 EPS vs JIS A9521 XPS
Polymer · grade comparison
JIS A9511 EPS and JIS A9521 XPS are both polymer grades. JIS A9521 XPS is the stronger of the two: tensile strength 0.4 MPa (0.058 ksi) against 0.2 MPa (0.029 ksi) for JIS A9511 EPS, about 100% more. JIS A9521 XPS is the more ductile: elongation 2% versus 1.5% for JIS A9511 EPS. JIS A9511 EPS is lighter (0.02 g/cm³ vs 0.03 g/cm³ for JIS A9521 XPS) and JIS A9521 XPS is stiffer (0.01 GPa vs 0.01 GPa). On the shop floor, JIS A9511 EPS welds better (poor vs not recommended).
JIS A9511 EPSChoose it when weight is the constraint, or when it will be welded.
JIS A9521 XPSChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
JIS A9511 EPS vs JIS A9521 XPS: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Compression Set (22 h, 70 °C)
Same in both: Poisson's Ratio 0.1
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Water Absorption (Saturation)
Same in both: Glass Transition (Tg) 100°C212 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Min Service Temperature
Vicat Softening Point (B50)
Limiting Oxygen Index
Same in both: Specific Heat Capacity 1,400 J/kg·K0.33 BTU/lb·°F · Max Service Temperature (continuous) 75°C167 °F · Max Service Temperature (short-term) 85°C185 °F
Electrical
Conductivity and insulation.
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Volume Resistivity 1×10¹⁶ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 15 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Mold Shrinkage
Mold Temperature (typ.)
Processing Melt Temperature (typ.)
Same in both: Machinability 90 / 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 | JIS A9511 EPS | JIS A9521 XPS |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
JIS A9511 EPS vs JIS A9521 XPS — frequently asked
Is JIS A9521 XPS stronger than JIS A9511 EPS?
Yes. JIS A9521 XPS has a typical tensile strength of 0.4 MPa (0.058 ksi) against 0.2 MPa (0.029 ksi) for JIS A9511 EPS — about 100% more.
Which is cheaper, JIS A9511 EPS or JIS A9521 XPS?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, JIS A9511 EPS or JIS A9521 XPS?
JIS A9511 EPS. Its weldability rates poor (30/100) against not recommended (5/100) for JIS A9521 XPS.
Ready to make it?
Upload a CAD file and FabDigit prices the part in JIS A9511 EPS and JIS A9521 XPS 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.