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PET vs PET-GF30

Polymer · grade comparison

PET and PET-GF30 are both polymer grades. PET-GF30 is the stronger of the two: tensile strength 150 MPa (21.8 ksi) against 82 MPa (11.9 ksi) for PET, about 83% more. In exchange, PET is the more ductile: elongation 20% versus 2.5% for PET-GF30, and PET-GF30 is harder (90 Shore D vs 85 Shore D). PET is lighter (1.39 g/cm³ vs 1.56 g/cm³ for PET-GF30) and PET-GF30 is stiffer (9.5 GPa vs 3.1 GPa). On the shop floor, PET machines more easily (very good vs fair) and PET welds better (fair vs poor).

PETChoose 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.

PET vs PET-GF30: properties

PETPET-GF30

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

3.1 GPa0.45 Msi
9.5 GPa1.4 Msi

Shear Modulus

1.1 GPa0.16 Msi
3.4 GPa0.49 Msi

Bulk Modulus

5 GPa0.65 Msi
—

Poisson's Ratio

0.4
0.39

Tensile Strength (Ultimate)

82 MPa11.9 ksi
150 MPa21.8 ksi

Yield Strength (0.2% offset)

80 MPa11.6 ksi
—

Elongation at Break

20%
2.5%

Compressive Strength

100 MPa14.5 ksi
150 MPa21.8 ksi

Compressive Modulus

3 GPa0.44 Msi
8.5 GPa1.2 Msi

Flexural Strength

120 MPa17.4 ksi
225 MPa32.6 ksi

Flexural Modulus

3.1 GPa0.45 Msi
9 GPa1.3 Msi

Shear Strength

55 MPa8 ksi
70 MPa10.2 ksi

Fracture Toughness (K_IC)

4 MPa·√m3.6 ksi·√in
3.5 MPa·√m3.2 ksi·√in

Izod Impact, Notched

40 J/m0.75 ft·lbf/in
85 J/m1.6 ft·lbf/in

Hardness, Shore D

85 Shore D
90 Shore D

Hardness, Rockwell M

94 HRM
98 HRM

Same in both: Hardness, Rockwell R 120 HRR

Physical

Density and transition temperatures.

Density

1.39 g/cm³0.05 lb/in³
1.56 g/cm³0.06 lb/in³

Water Absorption (24 h)

0.11%
0.12%

Water Absorption (Saturation)

0.5%
0.45%

Refractive Index

1.575
—

Light Transmission

88%
—

Same in both: Melting Temperature (Tm) 255°C491 °F · Glass Transition (Tg) 79°C174 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.25 W/m·K0.14 BTU/hr·ft·°F
0.29 W/m·K0.17 BTU/hr·ft·°F

Specific Heat Capacity

1,150 J/kg·K0.27 BTU/lb·°F
1,200 J/kg·K0.29 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

65 µm/m·K36.1 µin/in·°F
25 µm/m·K13.9 µin/in·°F

Max Service Temperature (continuous)

100°C212 °F
140°C284 °F

Min Service Temperature

-20°C-4 °F
-40°C-40 °F

Heat Deflection Temp. @ 0.45 MPa

115°C239 °F
245°C473 °F

Heat Deflection Temp. @ 1.8 MPa

80°C176 °F
224°C435 °F

Vicat Softening Point (B50)

180°C356 °F
250°C482 °F

Limiting Oxygen Index

22%
23%

Max Service Temperature (short-term)

150°C302 °F
220°C428 °F

Electrical

Conductivity and insulation.

Dielectric Strength

22 kV/mm559 V/mil
28 kV/mm711 V/mil

Dielectric Constant (1 MHz)

3.2
3.8

Dissipation Factor (1 MHz)

0.018
0.02

Comparative Tracking Index (CTI)

600 V
250 V

Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
72 / 100

Same in both: UV / Weathering Resistance 30 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

78 / 100
45 / 100

Weldability

45 / 100
30 / 100

Formability (cold)

50 / 100
10 / 100

Polishability

60 / 100
25 / 100

Mold Shrinkage

2%
0.3%

Same in both: Processing Melt Temperature (typ.) 280°C536 °F · Mold Temperature (typ.) 135°C275 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

82 MJ/kg35,254 BTU/lb
80 MJ/kg34,394 BTU/lb

Embodied Carbon (primary production)

2.8 kg CO₂/kg
3.2 kg CO₂/kg

Embodied Water

120 L/kg14.4 gal/lb
80 L/kg9.6 gal/lb

Typical Recycled Content

25%
0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

59 kN·m/kg
96 kN·m/kg

Specific Stiffness (E / density)

2.2 MN·m/kg
6.1 MN·m/kg

Same in both: Thermal Diffusivity 0.2 mm²/s · 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.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scalePET

Manufacturing and finishing

CapabilityPETPET-GF30
CNC machiningYes—
Sheet metalYes—
Injection moldingYes—
Default conditionUnfilled—
Relative cost$$ Standard$$ Standard
Min. machined wall0.5 mm—
Best machined surfaceRa 0.8 µm—
Chrome Plating (Plastic)Yes—
EMI Shielding CoatingYes—
PaintingYes—
Soft Touch CoatingYes—
Spray PaintingYes—
UV CoatingYes—

PET vs PET-GF30 — frequently asked

Is PET-GF30 stronger than PET?

Yes. PET-GF30 has a typical tensile strength of 150 MPa (21.8 ksi) against 82 MPa (11.9 ksi) for PET — about 83% more.

Which is cheaper, PET 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, PET or PET-GF30?

PET. Its machinability rates very good (78/100) against fair (45/100) for PET-GF30; for welding the order is PET first (fair, 45/100) then PET-GF30 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in PET 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.