PEEK-Medical-Grade GF30 vs PEEK-Medical-Grade ST
Polymer · PEEK-Medical-Grade grade comparison
PEEK-Medical-Grade GF30 and PEEK-Medical-Grade ST are two grades of the same polymer grade, PEEK-Medical-Grade: GF30 (30% glass fibre reinforced medical grade) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. PEEK-Medical-Grade GF30 is the stronger of the two: tensile strength 165 MPa (23.9 ksi) against 100 MPa (14.5 ksi) for PEEK-Medical-Grade ST, about 65% more. In exchange, PEEK-Medical-Grade ST is the more ductile: elongation 30% versus 2.5% for PEEK-Medical-Grade GF30. PEEK-Medical-Grade ST is lighter (1.3 g/cm³ vs 1.51 g/cm³ for PEEK-Medical-Grade GF30) and PEEK-Medical-Grade GF30 is stiffer (10.5 GPa vs 3.8 GPa). On the shop floor, PEEK-Medical-Grade ST machines more easily (very good vs fair).
PEEK-Medical-Grade GF30Choose it when strength drives the design.
PEEK-Medical-Grade STChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
PEEK-Medical-Grade GF30 vs PEEK-Medical-Grade ST: 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.
PEEK-Medical-Grade GF30PEEK-Medical-Grade ST
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 1.4 GPa0.2 Msi · Bulk Modulus 4 GPa0.62 Msi · Poisson's Ratio 0.4 · Yield Strength (0.2% offset) 98 MPa14.2 ksi · Compressive Strength 125 MPa18.1 ksi · Compressive Modulus 3.6 GPa0.52 Msi · Shear Strength 60 MPa8.7 ksi · Fracture Toughness (K_IC) 4 MPa·√m3.6 ksi·√in · Hardness, Shore D 85 Shore D · Hardness, Rockwell M 99 HRM · Hardness, Rockwell R 126 HRR
Physical
Density and transition temperatures.
Density
Same in both: Melting Temperature (Tm) 343°C649 °F · Glass Transition (Tg) 143°C289 °F · Water Absorption (24 h) 0.14% · Water Absorption (Saturation) 0.45%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
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: Specific Heat Capacity 1,340 J/kg·K0.32 BTU/lb·°F · Max Service Temperature (continuous) 250°C482 °F · Min Service Temperature -60°C-76 °F · Limiting Oxygen Index 35% · Max Service Temperature (short-term) 300°C572 °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) 3.2 · Dissipation Factor (1 MHz) 0.003 · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 150 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 95 / 100 · UV / Weathering Resistance 35 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Mold Shrinkage
Same in both: Weldability 60 / 100 · Polishability 80 / 100 · Melt Flow Rate 3.5 g/10 min · Processing Melt Temperature (typ.) 380°C716 °F · Mold Temperature (typ.) 190°C374 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 290 MJ/kg124,678 BTU/lb · Embodied Carbon (primary production) 13 kg CO₂/kg · Embodied Water 600 L/kg71.9 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.
PEEK-Medical-Grade GF30 vs PEEK-Medical-Grade ST — frequently asked
Is PEEK-Medical-Grade GF30 stronger than PEEK-Medical-Grade ST?
Yes. PEEK-Medical-Grade GF30 has a typical tensile strength of 165 MPa (23.9 ksi) against 100 MPa (14.5 ksi) for PEEK-Medical-Grade ST — about 65% more.
Which grade does FabDigit quote by default, GF30 or ST?
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, PEEK-Medical-Grade GF30 or PEEK-Medical-Grade ST?
PEEK-Medical-Grade ST. Its machinability rates very good (70/100) against fair (45/100) for PEEK-Medical-Grade GF30.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEEK-Medical-Grade GF30 and PEEK-Medical-Grade ST 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.