PP GF20 vs PP GF40
Polymer · PP grade comparison
PP GF20 and PP GF40 are two grades of the same polymer grade, PP: GF20 (20% glass-fiber reinforced) versus GF40 (40% glass-fiber reinforced). The chemistry is identical, so every difference below comes from the condition. PP GF40 is the stronger of the two: tensile strength 100 MPa (14.5 ksi) against 65 MPa (9.43 ksi) for PP GF20, about 54% more. In exchange, PP GF20 is the more ductile: elongation 4% versus 2.5% for PP GF40. PP GF20 is lighter (1.04 g/cm³ vs 1.22 g/cm³ for PP GF40) and PP GF40 is stiffer (8.8 GPa vs 4.5 GPa).
PP GF20Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
PP GF40Choose it when strength drives the design, or when the part sees heat.
PP GF20 vs PP GF40: 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
Flexural Strength
Flexural Modulus
Izod Impact, Notched
Same in both: Shear Modulus 0.55 GPa0.08 Msi · Bulk Modulus 3 GPa0.45 Msi · Poisson's Ratio 0.42 · Yield Strength (0.2% offset) 33 MPa4.8 ksi · Compressive Strength 42 MPa6.1 ksi · Compressive Modulus 1.4 GPa0.2 Msi · Shear Strength 25 MPa3.6 ksi · Fracture Toughness (K_IC) 3.5 MPa·√m3.2 ksi·√in · Hardness, Shore D 72 Shore D · Hardness, Rockwell R 95 HRR
Physical
Density and transition temperatures.
Density
Same in both: Melting Temperature (Tm) 165°C329 °F · Glass Transition (Tg) -10°C14 °F · Water Absorption (24 h) 0.02% · Water Absorption (Saturation) 0.1% · Refractive Index 1.49
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. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
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 -10°C14 °F · Vicat Softening Point (B50) 90°C194 °F · Limiting Oxygen Index 18% · Max Service Temperature (short-term) 130°C266 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dielectric Strength 25 kV/mm635 V/mil · Dielectric Constant (1 MHz) 2.25 · Dissipation Factor (1 MHz) 3×10⁻⁴ · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 92 / 100 · UV / Weathering Resistance 20 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Mold Shrinkage
Same in both: Weldability 92 / 100 · Formability (cold) 80 / 100 · Polishability 40 / 100 · Melt Flow Rate 12 g/10 min · Processing Melt Temperature (typ.) 230°C446 °F · Mold Temperature (typ.) 40°C104 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 78 MJ/kg33,534 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 100 L/kg12 gal/lb · Typical Recycled Content 5%
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.
PP GF20 vs PP GF40 — frequently asked
Is PP GF40 stronger than PP GF20?
Yes. PP GF40 has a typical tensile strength of 100 MPa (14.5 ksi) against 65 MPa (9.43 ksi) for PP GF20 — about 54% more.
Which grade does FabDigit quote by default, GF20 or GF40?
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, PP GF20 or PP GF40?
PP GF20, by a small margin. Both rate fair for machinability — 50/100 against 42/100 for PP GF40.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PP GF20 and PP GF40 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.