PBT vs PET-GF30
Polymer · grade comparison
PBT and PET-GF30 are both polymer grades. PET-GF30 is the stronger of the two: tensile strength 150 MPa (21.8 ksi) against 55 MPa (7.98 ksi) for PBT, about 173% more. In exchange, PBT is the more ductile: elongation 100% versus 2.5% for PET-GF30, and PET-GF30 is harder (90 Shore D vs 82 Shore D). PBT is lighter (1.31 g/cm³ vs 1.56 g/cm³ for PET-GF30) and PET-GF30 is stiffer (9.5 GPa vs 2.6 GPa). On the shop floor, PBT machines more easily (good vs fair) and PBT welds better (very good vs poor).
PBTChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
PET-GF30Choose it when strength drives the design, or when the part sees heat.
PBT vs PET-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
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Same in both: Water Absorption (Saturation) 0.45%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Limiting Oxygen Index
Max Service Temperature (short-term)
Same in both: Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Comparative Tracking Index (CTI)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dissipation Factor (1 MHz) 0.02 · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 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.
Manufacturing and finishing
| Capability | PBT | PET-GF30 |
|---|---|---|
| Injection molding | Yes | — |
| Default condition | Unfilled | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
| Chrome Plating (Plastic) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Soft Touch Coating | Yes | — |
| Spray Painting | Yes | — |
| UV Coating | Yes | — |
PBT vs PET-GF30 — frequently asked
Is PET-GF30 stronger than PBT?
Yes. PET-GF30 has a typical tensile strength of 150 MPa (21.8 ksi) against 55 MPa (7.98 ksi) for PBT — about 173% more.
Which is cheaper, PBT or PET-GF30?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, PBT or PET-GF30?
PBT. Its machinability rates good (68/100) against fair (45/100) for PET-GF30; for welding the order is PBT first (very good, 70/100) then PET-GF30 (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PBT and PET-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.