SAN GF20 vs SAN GF40
Polymer · SAN grade comparison
SAN GF20 and SAN GF40 are two grades of the same polymer grade, SAN: GF20 (20% Glass Fiber reinforced SAN) versus GF40 (40% Glass Fiber reinforced SAN). The chemistry is identical, so every difference below comes from the condition. SAN GF40 is the stronger of the two: tensile strength 130 MPa (18.9 ksi) against 95 MPa (13.8 ksi) for SAN GF20, about 37% more. In exchange, SAN GF20 is the more ductile: elongation 2.2% versus 1.5% for SAN GF40. SAN GF20 is lighter (1.22 g/cm³ vs 1.41 g/cm³ for SAN GF40) and SAN GF40 is stiffer (12 GPa vs 7 GPa). On the shop floor, SAN GF20 machines more easily (45 vs 35 out of 100) and SAN GF20 welds better (very good vs fair).
SAN GF20Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
SAN GF40Choose it when strength drives the design.
SAN GF20 vs SAN 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
Hardness, Rockwell M
Same in both: Shear Modulus 1.3 GPa0.19 Msi · Bulk Modulus 4 GPa0.58 Msi · Poisson's Ratio 0.35 · Yield Strength (0.2% offset) 70 MPa10.2 ksi · Compressive Strength 100 MPa14.5 ksi · Compressive Modulus 3.5 GPa0.51 Msi · Shear Strength 45 MPa6.5 ksi · Fracture Toughness (K_IC) 1.5 MPa·√m1.4 ksi·√in · Hardness, Shore D 84 Shore D · Hardness, Rockwell R 120 HRR
Physical
Density and transition temperatures.
Density
Same in both: Glass Transition (Tg) 106°C223 °F · Water Absorption (24 h) 0.25% · Water Absorption (Saturation) 0.9% · Refractive Index 1.571 · Light Transmission 0%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
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: Specific Heat Capacity 1,350 J/kg·K0.32 BTU/lb·°F · Min Service Temperature -30°C-22 °F · Vicat Softening Point (B50) 105°C221 °F · Limiting Oxygen Index 19% · Max Service Temperature (short-term) 95°C203 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dielectric Strength 22 kV/mm559 V/mil · Dielectric Constant (1 MHz) 2.9 · Dissipation Factor (1 MHz) 0.008 · 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 72 / 100 · UV / Weathering Resistance 32 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Mold Shrinkage
Same in both: Formability (cold) 45 / 100 · Polishability 88 / 100 · Melt Flow Rate 10 g/10 min · Processing Melt Temperature (typ.) 240°C464 °F · Mold Temperature (typ.) 65°C149 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 96 MJ/kg41,273 BTU/lb · Embodied Carbon (primary production) 3.5 kg CO₂/kg · Embodied Water 180 L/kg21.6 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.
SAN GF20 vs SAN GF40 — frequently asked
Is SAN GF40 stronger than SAN GF20?
Yes. SAN GF40 has a typical tensile strength of 130 MPa (18.9 ksi) against 95 MPa (13.8 ksi) for SAN GF20 — about 37% 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, SAN GF20 or SAN GF40?
SAN GF20, by a small margin. Both rate fair for machinability — 45/100 against 35/100 for SAN GF40; for welding the order is SAN GF20 first (very good, 70/100) then SAN GF40 (fair, 50/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in SAN GF20 and SAN 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.