PEEK
ASTM D6402, F2026 · also APTIV, KetaSpire
PEEK (Victrex, KetaSpire; ASTM F2026) is a semi-crystalline polyaryletherketone with a Tg near 143 °C, a melting point near 343 °C and 250 °C continuous service, high fatigue and wear resistance, resistance to hydrolysis and most chemicals, and inherent UL94 V-0.
PEEK grades and fills
PEEK is supplied in 10 conditions, soft to hard.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
FDM/FFF 3D-printed PEEK, as printed (no post-anneal) | Use for prototypes and low-load fixtures; expect anisotropy, partial crystallinity and Z-direction strength far below molded PEEK. | 85 | 10 | ||
10% PTFE lubricated | Pick for low-friction sliding parts that must stay electrically insulating and reasonably tough (no fiber reinforcement). | 90 | 15 | 83 Shore D | |
Standard injection-molding grade (medium viscosity, unfilled) | Default choice for general injection-molded PEEK parts where flow and toughness are balanced. | 100 | 100 | 40 | 85 Shore D |
Annealed / stress-relieved (printed or machined parts, ~200–300 °C soak) | Specify after printing or heavy machining to raise crystallinity, restore heat resistance and prevent dimensional drift in service. | 100 | 95 | 12 | 87 Shore D |
ESD / static-dissipative PEEK | Pick for semiconductor wafer handling, test sockets and fuel-system parts where charge build-up must be bled off. | 110 | 4 | 88 Shore D | |
Bearing / tribological grade (≈10% PTFE + 10% graphite + 10% carbon fiber, Victrex 450FC30 / TECAPEEK TF10 class) | Pick for dry-running bushings, wear rings, seals and thrust washers needing low friction and low wear rate at high PV. | 125 | 2.5 | ||
20% Glass Fiber | PEEK compounded with 20% short glass fiber — higher stiffness, strength and creep resistance than unfilled PEEK with HDT near the melting point, at the cost of ductility and impact. | 140 | 3 | 87 Shore D | |
10% carbon-fiber reinforced | Pick when moderate stiffness gain and dimensional stability are wanted while keeping some ductility and machinability. | 145 | 5 | ||
30% glass-fiber reinforced | Pick for high stiffness and creep resistance at 200–260 °C when electrical insulation must be retained. | 165 | 165 | 2.5 | 105 HRM |
30% carbon-fiber reinforced | Pick for highest strength/stiffness-to-weight, low CTE, better heat dissipation and static-dissipative behaviour. | 225 | 225 | 1.8 | 107 HRM |
Supply forms, finishes and certifications
Ways PEEK is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FDA | FDA / food-contact and medical-grade unfilled PEEK | Certification |
UnfilledDefault | Unfilled / natural PEEK | Standard supply |
VirginDefault | Virgin resin (no regrind), prime lot certified | Standard supply |
What is PEEK?
PEEK (Victrex, KetaSpire; ASTM F2026) is a semi-crystalline polyaryletherketone with a Tg near 143 °C, a melting point near 343 °C and 250 °C continuous service, high fatigue and wear resistance, resistance to hydrolysis and most chemicals, and inherent UL94 V-0. Unfilled stock is 1.3 g/cm³ with 100 MPa tensile strength and 3.7 GPa modulus; GF30, CF30, PTFE bearing, FDA and ESD grades are stocked for structural and sealing parts. Resin costs one to two orders of magnitude more than general engineering plastics, processing needs 360–400 °C melt with 170–200 °C moulds, and concentrated sulphuric acid and long-term UV attack it. PEEK has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 143°C (289 °F). PEEK has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 100 MPa (14.5 ksi) — stronger than 95% of polymer grades. Elongation at break is 30% and the elastic modulus is 3.7 GPa (0.537 Msi).
What is PEEK used for?
- Spinal fusion implants
- Aerospace seals and back-up rings
- Downhole oil and gas seals
- Semiconductor wafer handling fixtures
- Bearings, bushings and wear pads
- Compressor valve plates
- Steam-sterilisable surgical instrument components
- High-temperature electrical insulators
Advantages
- High strength — 100 MPa (14.5 ksi), better than 95% of polymer grades
- High service temperature — 250°C (482 °F), better than 94% of polymer grades
- Stiff — 3.7 GPa (0.537 Msi), better than 84% of polymer grades
- Good corrosion resistance — 90/100, better than 82% of polymer grades
- Tough — resists crack growth — 3.5 MPa·√m (3.19 ksi·√in), better than 81% of polymer grades
Limitations
- High embodied carbon — 15 kg CO₂/kg, worse than 96% of polymer grades
PEEK properties
Typical room-temperature values in the Virgin condition; bars are the position among polymer grades.
Physical5
PEEK has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 143°C (289 °F).
Mechanical17
PEEK has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 100 MPa (14.5 ksi) — stronger than 95% of polymer grades. Elongation at break is 30% and the elastic modulus is 3.7 GPa (0.537 Msi).
Thermal11
PEEK is rated for continuous service to 250°C (482 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 72% of polymer grades. Thermal expansion is 47 µm/m·K (26.1 µin/in·°F).
Electrical7
PEEK is an electrical insulator with a dielectric strength of 21 kV/mm (533.4 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 82% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PEEK takes about 290 MJ of energy and emits 15 kg of CO₂ — more than 95% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PEEK's machinability is very good (70/100, better than 74% of polymer grades); weldability fair (45/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PEEK is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PEEK
Is PEEK easy to machine?
Machines cleanly with sharp carbide (polished flutes, positive rake) and air/flood cooling; glass- and carbon-filled grades are abrasive and want diamond-coated tooling, and thick machined parts should be annealed before finish cuts to avoid stress cracking.
Can PEEK be welded?
Joins by ultrasonic, laser, hot-plate, spin and infrared welding at 380–400 °C interface temperature; no solvent bonding — adhesive joints need plasma or abrasive surface activation.
Can PEEK be formed, bent or molded?
Inject at 360–400 °C melt with 170–200 °C mold for full crystallinity; resin must be dried (150 °C, 3 h), runners/gates generous, and slow crystallising thin sections may need post-mold annealing.
Manufacturability
The process limits FabDigit's quote engine applies to PEEK. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Better70 / 100 |
|---|---|
| ISO material group | N.8 |
| Cutting speed (rough / finish) | 250 / 310 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 8× diameter |
| Best surface (machined / polished) | Ra 0.8 / 0.4 µm |
| Hardenable after machining | No |
Sheet metal
| Formability | Not Recommend30 / 100 |
|---|---|
| Weldability | Better45 / 100 |
Injection molding
| Mold shrinkage | 1.5 – 2.2 % |
|---|---|
| Wall thickness | 1 – 3.5 mm |
| Recommended draft | 1.5 ° |
| Pre-drying | 80 °C for 4 h |
| UV resistance | Fair |
3D printing
| Technologies | FDM |
|---|---|
| Layer height | 50 – 300 µmdefault 100 µm |
| Minimum wall / feature | 1 / 0.5 mm |
| Build envelope | 300 × 300 × 380 mm |
| Supports | Yes |
| Anisotropy | Moderate |
PEEK chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| glass fiberGF variants only (chopped E-glass, sized for PAEK) | 10 – 40 | 30 |
| carbon fiberCF variants only (PAN-based chopped fiber) | 10 – 40 | 30 |
| PTFEbearing / lubricated variants | 5 – 15 | 10 |
| graphitebearing variants | 5 – 10 | 10 |
| carbon blackblack / ESD variants | 1 – 15 | 3 |
| poly(oxy-1,4-phenylene-oxy-1,4-phenyleneUnfilled grade; polymerised from 4,4'-difluorobenzophenone + hydroquinone in diphenyl sulfone | balance |
What surface finishes work on PEEK?
Can be machined-to-finish, bead-blasted, laser-marked or plasma treated for printing/metallising; not paintable without primer and not anodizable — parts are usually left natural tan or supplied in black.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Coating
Injection Molding Coating
Organic Coating
Metallization / Functional
Coloring
Equivalent designations
Standards and trade names that resolve to PEEK in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D6402F2026
- Trade names
- APTIVKetaSpireTECAPEEKVictrexVICTREX PEEK
- Also called
- Poly-Ether-Ether-KetonePolyetheretherketone
How much does PEEK cost?
PEEK is a specialty-cost polymer ($$$$$), pricier than about 99% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PEEK — frequently asked
What is PEEK used for?
PEEK is typically used for spinal fusion implants, aerospace seals and back-up rings, downhole oil and gas seals, semiconductor wafer handling fixtures, bearings, bushings and wear pads and compressor valve plates. In short: ultra-performance plastic.
What is the yield strength of PEEK?
PEEK has a typical yield strength of 100 MPa (14.5 ksi) and a tensile strength of 100 MPa (14.5 ksi) — stronger than 95% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is PEEK easy to machine?
Yes — machinability is rated very good (70/100, better than 74% of polymer grades). Machines cleanly with sharp carbide (polished flutes, positive rake) and air/flood cooling; glass- and carbon-filled grades are abrasive and want diamond-coated tooling, and thick machined parts should be annealed before finish cuts to avoid stress cracking.
Can PEEK be welded?
With care — weldability is rated fair (45/100). Joins by ultrasonic, laser, hot-plate, spin and infrared welding at 380–400 °C interface temperature; no solvent bonding — adhesive joints need plasma or abrasive surface activation.
What surface finishes work on PEEK?
Can be machined-to-finish, bead-blasted, laser-marked or plasma treated for printing/metallising; not paintable without primer and not anodizable — parts are usually left natural tan or supplied in black.
Can PEEK be formed, bent or molded?
Inject at 360–400 °C melt with 170–200 °C mold for full crystallinity; resin must be dried (150 °C, 3 h), runners/gates generous, and slow crystallising thin sections may need post-mold annealing.
What is the maximum service temperature of PEEK?
PEEK is rated for continuous use to about 250°C (482 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PEEK cost?
PEEK is a specialty-cost polymer ($$$$$), pricier than about 99% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in PEEK?
Yes — PEEK is available for CNC machining, sheet metal, injection molding and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- VICTREX PEEK 450G / 450GL30 / 450CA30 / 450FC30 product datasheets — Victrex plc (2023)
- KetaSpire PEEK design & processing guide — Solvay Specialty Polymers (2022)
- TECAPEEK stock shape property tables — Ensinger GmbH (2023)
- CAMPUS plastics multipoint data for PEEK grades — CWFG / CAMPUS (2024)
- ASM Engineered Materials Handbook: Engineering Plastics — ASM International (1988)
- ISO 527 / ISO 178 / ISO 75 / ISO 180 test methods; ASTM D638, D790, D648 — ISO / ASTM (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.