PEI CF30 vs PEI GF30
Polymer · PEI grade comparison
PEI CF30 and PEI GF30 are two grades of the same polymer grade, PEI: CF30 (30% carbon fiber reinforced PEI) versus GF30 (30% glass fiber reinforced). The chemistry is identical, so every difference below comes from the condition. PEI CF30 is the stronger of the two: tensile strength 200 MPa (29 ksi) against 165 MPa (23.9 ksi) for PEI GF30, about 21% more. In exchange, PEI GF30 is the more ductile: elongation 3% versus 1.8% for PEI CF30. PEI CF30 is lighter (1.42 g/cm³ vs 1.51 g/cm³ for PEI GF30) and PEI CF30 is stiffer (19 GPa vs 9 GPa).
PEI CF30Choose it when strength drives the design, or when weight is the constraint.
PEI GF30Choose it when the part is bent, formed or impact-loaded.
PEI CF30 vs PEI GF30: 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)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Izod Impact, Notched
Hardness, Rockwell M
Same in both: Shear Modulus 1.2 GPa0.17 Msi · Bulk Modulus 4 GPa0.55 Msi · Poisson's Ratio 0.36 · Yield Strength (0.2% offset) 105 MPa15.2 ksi · Compressive Modulus 3 GPa0.44 Msi · Shear Strength 85 MPa12.3 ksi · Fracture Toughness (K_IC) 3 MPa·√m2.7 ksi·√in · Hardness, Shore D 87 Shore D · Hardness, Rockwell R 125 HRR
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Same in both: Glass Transition (Tg) 217°C423 °F · Water Absorption (Saturation) 1.25% · Refractive Index 1.66 · Light Transmission 78%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Same in both: Specific Heat Capacity 1,100 J/kg·K0.26 BTU/lb·°F · Max Service Temperature (continuous) 170°C338 °F · Min Service Temperature -50°C-58 °F · Heat Deflection Temp. @ 0.45 MPa 210°C410 °F · Heat Deflection Temp. @ 1.8 MPa 210°C410 °F · Vicat Softening Point (B50) 219°C426 °F · Limiting Oxygen Index 47% · Max Service Temperature (short-term) 200°C392 °F
Electrical
Conductivity and insulation.
Surface Resistivity
Same in both: Electrical Resistivity 1×10¹⁵ Ω·m3.94×10²² µΩ·in · Dielectric Strength 33 kV/mm838 V/mil · Dielectric Constant (1 MHz) 3.15 · Dissipation Factor (1 MHz) 0.0013 · Volume Resistivity 1×10¹⁷ Ω·cm · Comparative Tracking Index (CTI) 175 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 85 / 100 · UV / Weathering Resistance 40 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Mold Shrinkage
Same in both: Weldability 60 / 100 · Formability (cold) 45 / 100 · Polishability 70 / 100 · Melt Flow Rate 9 g/10 min · Processing Melt Temperature (typ.) 370°C698 °F · Mold Temperature (typ.) 150°C302 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 230 MJ/kg98,882 BTU/lb · Embodied Carbon (primary production) 9 kg CO₂/kg · Embodied Water 400 L/kg47.9 gal/lb · Typical Recycled Content 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.
PEI CF30 vs PEI GF30 — frequently asked
Is PEI CF30 stronger than PEI GF30?
Yes. PEI CF30 has a typical tensile strength of 200 MPa (29 ksi) against 165 MPa (23.9 ksi) for PEI GF30 — about 21% more.
Which grade does FabDigit quote by default, CF30 or GF30?
Unfilled (1000) is the default PEI condition in the FabDigit quote flow (neither CF30 nor GF30). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, PEI CF30 or PEI GF30?
PEI GF30, by a small margin. Both rate fair for machinability — 45/100 against 40/100 for PEI CF30.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEI CF30 and PEI GF30 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.