PEEK-ESD vs PEK
Polymer · grade comparison
PEEK-ESD and PEK are both polymer grades. PEK is the stronger of the two: yield strength 105 MPa (15.2 ksi) against 88 MPa (12.8 ksi) for PEEK-ESD, about 19% more; tensile strength follows at 110 MPa (16 ksi) vs 90 MPa (13.1 ksi). PEK is the more ductile: elongation 25% versus 6% for PEEK-ESD. PEK is lighter (1.3 g/cm³ vs 1.42 g/cm³ for PEEK-ESD) and PEEK-ESD conducts heat better (0.42 W/m·K vs 0.25 W/m·K). On the shop floor, PEK welds better (good vs fair).
PEKChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
PEEK-ESD 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
Poisson's Ratio
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: Compressive Modulus 3.8 GPa0.55 Msi · Hardness, Rockwell M 100 HRM
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
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: Specific Heat Capacity 1,340 J/kg·K0.32 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 45 µm/m·K25 µin/in·°F
Electrical
Conductivity and insulation.
Electrical Resistivity
Volume Resistivity
Surface Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Comparative Tracking Index (CTI)
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
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 | PEEK-ESD | PEK |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
PEEK-ESD vs PEK — frequently asked
Is PEK stronger than PEEK-ESD?
Yes. PEK has a typical yield strength of 105 MPa (15.2 ksi) against 88 MPa (12.8 ksi) for PEEK-ESD — about 19% more. Tensile strength is 110 MPa (16 ksi) vs 90 MPa (13.1 ksi).
Which is cheaper, PEEK-ESD or PEK?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, PEEK-ESD or PEK?
PEK, by a small margin. Both rate good for machinability — 65/100 against 60/100 for PEEK-ESD; for welding the order is PEK first (good, 55/100) then PEEK-ESD (fair, 40/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEEK-ESD 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.