HDPE GF30 vs HDPE INJ
Polymer · HDPE grade comparison
HDPE GF30 and HDPE INJ are two grades of the same polymer grade, HDPE: GF30 (30% glass fiber reinforced HDPE) versus INJ (injection moulding grade). The chemistry is identical, so every difference below comes from the condition. HDPE INJ is the stronger of the two: yield strength 28 MPa (4.06 ksi) against 26 MPa (3.77 ksi) for HDPE GF30, about 8% more. HDPE INJ is the more ductile: elongation 300% versus 3% for HDPE GF30, and HDPE GF30 is harder (72 Shore D vs 66 Shore D). HDPE INJ is lighter (0.96 g/cm³ vs 1.18 g/cm³ for HDPE GF30) and HDPE GF30 is stiffer (5.5 GPa vs 1.3 GPa). On the shop floor, HDPE INJ machines more easily (good vs fair) and HDPE INJ welds better (excellent vs fair).
HDPE INJChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
HDPE GF30 vs HDPE INJ: 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)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell R
Same in both: Shear Modulus 0.4 GPa0.06 Msi · Bulk Modulus 3 GPa0.44 Msi · Poisson's Ratio 0.44 · Compressive Modulus 0.9 GPa0.13 Msi
Physical
Density and transition temperatures.
Density
Same in both: Melting Temperature (Tm) 132°C270 °F · Glass Transition (Tg) -110°C-166 °F · Water Absorption (24 h) 0.01% · Water Absorption (Saturation) 0.05% · Refractive Index 1.54
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Same in both: Thermal Conductivity 0.48 W/m·K0.28 BTU/hr·ft·°F · Specific Heat Capacity 1,900 J/kg·K0.45 BTU/lb·°F · Max Service Temperature (continuous) 80°C176 °F · Min Service Temperature -80°C-112 °F · Limiting Oxygen Index 18% · Max Service Temperature (short-term) 110°C230 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dielectric Strength 24 kV/mm610 V/mil · Dielectric Constant (1 MHz) 2.35 · 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 90 / 100 · UV / Weathering Resistance 25 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Same in both: Polishability 30 / 100 · 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 90 L/kg10.8 gal/lb · Typical Recycled Content 10%
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.
HDPE GF30 vs HDPE INJ — frequently asked
Is HDPE INJ stronger than HDPE GF30?
Yes. HDPE INJ has a typical yield strength of 28 MPa (4.06 ksi) against 26 MPa (3.77 ksi) for HDPE GF30 — about 8% more. Tensile strength is 29 MPa (4.21 ksi) vs 55 MPa (7.98 ksi).
Which grade does FabDigit quote by default, GF30 or INJ?
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, HDPE GF30 or HDPE INJ?
HDPE INJ. Its machinability rates good (60/100) against fair (50/100) for HDPE GF30; for welding the order is HDPE INJ first (excellent, 88/100) then HDPE GF30 (fair, 45/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in HDPE GF30 and HDPE INJ 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.