PEEK-Medical-Grade vs PEK
Polymer · grade comparison
PEEK-Medical-Grade and PEK are both polymer grades. PEK is the stronger of the two: yield strength 105 MPa (15.2 ksi) against 98 MPa (14.2 ksi) for PEEK-Medical-Grade, about 7% more; tensile strength follows at 110 MPa (16 ksi) vs 100 MPa (14.5 ksi). In exchange, PEEK-Medical-Grade is the more ductile: elongation 30% versus 25% for PEK. PEK is stiffer (4 GPa vs 3.8 GPa).
PEEK-Medical-GradeChoose it when the part is bent, formed or impact-loaded.
PEKChoose it when strength drives the design.
PEEK-Medical-Grade vs PEK: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Same in both: Poisson's Ratio 0.4 · Flexural Strength 165 MPa23.9 ksi
Physical
Density and transition temperatures.
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Same in both: Density 1.3 g/cm³0.05 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
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: Thermal Conductivity 0.25 W/m·K0.14 BTU/hr·ft·°F · Specific Heat Capacity 1,340 J/kg·K0.32 BTU/lb·°F
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Surface Resistivity
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dissipation Factor (1 MHz) 0.003 · Volume Resistivity 1×10¹⁶ Ω·cm · Comparative Tracking Index (CTI) 150 V
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
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Same in both: Thermal Diffusivity 0.1 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.
Manufacturing and finishing
| Capability | PEEK-Medical-Grade | PEK |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
PEEK-Medical-Grade vs PEK — frequently asked
Is PEK stronger than PEEK-Medical-Grade?
Yes. PEK has a typical yield strength of 105 MPa (15.2 ksi) against 98 MPa (14.2 ksi) for PEEK-Medical-Grade — about 7% more. Tensile strength is 110 MPa (16 ksi) vs 100 MPa (14.5 ksi).
Which is cheaper, PEEK-Medical-Grade or PEK?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, PEEK-Medical-Grade or PEK?
PEEK-Medical-Grade. Its machinability rates very good (70/100) against good (65/100) for PEK; for welding the order is PEEK-Medical-Grade first (good, 60/100) then PEK (good, 55/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEEK-Medical-Grade and PEK 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.