BIIR vs CIIR
Polymer · grade comparison
BIIR and CIIR are both polymer grades. CIIR is the stronger of the two: tensile strength 12 MPa (1.74 ksi) against 11 MPa (1.6 ksi) for BIIR, about 9% more. BIIR is lighter (1.13 g/cm³ vs 1.18 g/cm³ for CIIR).
BIIRChoose it when weight is the constraint.
CIIRChoose it when strength drives the design.
BIIR vs CIIR: 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.
Tensile Strength (Ultimate)
Shear Strength
Compression Set (22 h, 70 °C)
Same in both: Elastic (Young's) Modulus 0 GPa5.8×10⁻⁴ Msi · Shear Modulus 0 GPa1.89×10⁻⁴ Msi · Bulk Modulus 2 GPa0.29 Msi · Poisson's Ratio 0.5 · Elongation at Break 500% · Hardness, Shore A 60 Shore A · Hardness, Shore D 15 Shore D · Tear Strength 30 kN/m171 lbf/in
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Refractive Index
Same in both: Glass Transition (Tg) -60°C-76 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Limiting Oxygen Index
Max Service Temperature (short-term)
Same in both: Thermal Conductivity 0.22 W/m·K0.13 BTU/hr·ft·°F · Specific Heat Capacity 1,900 J/kg·K0.45 BTU/lb·°F · Min Service Temperature -45°C-49 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume 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.
Weldability
Formability (cold)
Mold Shrinkage
Mold Temperature (typ.)
Processing Melt Temperature (typ.)
Same in both: Machinability 30 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Same in both: Embodied Carbon (primary production) 3.6 kg CO₂/kg · Embodied Water 180 L/kg21.6 gal/lb · Typical Recycled Content 5%
Common Calculations
Ratios derived from the values above.
Thermal Shock Resistance Index
Same in both: Specific Strength (UTS / density) 10 kN·m/kg · Specific Stiffness (E / density) 0 MN·m/kg · Thermal Diffusivity 0.1 mm²/s
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 | BIIR | CIIR |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
BIIR vs CIIR — frequently asked
Is CIIR stronger than BIIR?
Yes. CIIR has a typical tensile strength of 12 MPa (1.74 ksi) against 11 MPa (1.6 ksi) for BIIR — about 9% more.
Which is cheaper, BIIR or CIIR?
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.
When should I choose BIIR over CIIR?
Pick BIIR when weight is the constraint. Pick CIIR when strength drives the design.
Ready to make it?
Upload a CAD file and FabDigit prices the part in BIIR and CIIR 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.