PEK BG vs PEK CF30
Polymer · PEK grade comparison
PEK BG and PEK CF30 are two grades of the same polymer grade, PEK: BG (bearing grade) versus CF30 (30 % short carbon fiber reinforced). The chemistry is identical, so every difference below comes from the condition. PEK CF30 is the stronger of the two: tensile strength 220 MPa (31.9 ksi) against 130 MPa (18.9 ksi) for PEK BG, about 69% more. PEK CF30 is stiffer (23 GPa vs 10 GPa). On the shop floor, PEK BG machines more easily (good vs fair).
PEK BGChoose it when the part is machined in volume.
PEK CF30Choose it when strength drives the design.
PEK BG vs PEK CF30: 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 1.4 GPa0.2 Msi · Poisson's Ratio 0.4 · Yield Strength (0.2% offset) 105 MPa15.2 ksi · Compressive Modulus 3.8 GPa0.55 Msi · Shear Strength 65 MPa9.4 ksi · Fracture Toughness (K_IC) 3.5 MPa·√m3.2 ksi·√in · Hardness, Shore D 87 Shore D
Physical
Density and transition temperatures.
Same in both: Density 1.44 g/cm³0.05 lb/in³ · Melting Temperature (Tm) 373°C703 °F · Glass Transition (Tg) 157°C315 °F · Water Absorption (24 h) 0.1% · Water Absorption (Saturation) 0.4%
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Heat Deflection Temp. @ 1.8 MPa
Same in both: Thermal Conductivity 0.9 W/m·K0.52 BTU/hr·ft·°F · Specific Heat Capacity 1,340 J/kg·K0.32 BTU/lb·°F · Min Service Temperature -70°C-94 °F · Heat Deflection Temp. @ 0.45 MPa 320°C608 °F · Vicat Softening Point (B50) 180°C356 °F · Limiting Oxygen Index 40% · Max Service Temperature (short-term) 320°C608 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Volume Resistivity
Same in both: Dielectric Strength 20 kV/mm508 V/mil · Dielectric Constant (1 MHz) 3.3 · Dissipation Factor (1 MHz) 0.003 · Surface Resistivity 1×10¹⁶ Ω · Comparative Tracking Index (CTI) 150 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 90 / 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 55 / 100 · Formability (cold) 25 / 100 · Polishability 70 / 100 · Melt Flow Rate 4 g/10 min · Processing Melt Temperature (typ.) 400°C752 °F · Mold Temperature (typ.) 200°C392 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 320 MJ/kg137,575 BTU/lb · Embodied Carbon (primary production) 22 kg CO₂/kg · 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.
PEK BG vs PEK CF30 — frequently asked
Is PEK CF30 stronger than PEK BG?
Yes. PEK CF30 has a typical tensile strength of 220 MPa (31.9 ksi) against 130 MPa (18.9 ksi) for PEK BG — about 69% more.
Which grade does FabDigit quote by default, BG or CF30?
Specify the condition in the material field or the drawing note; FabDigit prices the quote for the state you call out.
Which is easier to machine, PEK BG or PEK CF30?
PEK BG. Its machinability rates good (55/100) against fair (45/100) for PEK CF30.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEK BG and PEK CF30 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.