PEKK
also Kepstan
PEKK is a high-ketone-content semi-crystalline polyaryletherketone (Kepstan) supplied as FFF filament and SLS powder in unfilled, CF, GF30, ESD, medical and 6000/7000/8000 series grades.
PEKK grades and fills
PEKK is supplied in 8 conditions, soft to hard.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
SLS powder | 71 | 1.2 | |||
ESD / static-dissipative | Use for satellite, fuel-system and electronics-handling parts requiring controlled surface resistivity without sacrificing PEKK's heat and FST behaviour. | 85 | 87 | 2.5 | 87 Shore D |
FFF/FDM filament grade | Pick when quoting as-printed extruded parts; expect strong anisotropy with Z-direction roughly 60–70 % of in-plane strength. | 90 | 93 | 4 | 86 Shore D |
Kepstan 6000-type | Pick when the widest processing window and lowest melt temperature are needed (powder bed fusion, composite prepreg, coatings). | 100 | 100 | 25 | 85 Shore D |
Kepstan 7000-type | General-purpose balance of crystallisation rate, heat performance and processability; typical basis for filament and injection grades. | 100 | 100 | 15 | 86 Shore D |
Kepstan 8000-type | Use only when maximum crystallinity, chemical resistance and short-term temperature capability justify the very narrow 400 °C+ processing window. | 105 | 105 | 8 | 87 Shore D |
Carbon-fiber reinforced | Use where maximum stiffness, dimensional stability and low CTE are needed (aerospace brackets, tooling); sacrifices ductility and abrades tooling. | 145 | 2 | ||
30 % glass-fiber reinforced | Pick for stiff, creep-resistant, electrically insulating parts at elevated temperature at lower cost than carbon fiber. | 160 | 2.5 |
Supply forms, finishes and certifications
Ways PEKK is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
SLS-PWD | Laser-sintering powder grade | Printing process |
MED | Medical / implantable grade | Certification |
UnfilledDefault | Natural/unreinforced PEKK | Standard supply |
What is PEKK?
PEKK is a high-ketone-content semi-crystalline polyaryletherketone (Kepstan) supplied as FFF filament and SLS powder in unfilled, CF, GF30, ESD, medical and 6000/7000/8000 series grades. Tg is 160–165 °C and the melting point is tunable between 305 and 360 °C through the para/meta (T/I) isomer ratio, giving a wider processing window than PEEK; typical values are 1.3 g/cm3, 95 MPa tensile strength, 8 % elongation, 3.9 GPa modulus and 240 °C service, with inherent V-0 behaviour, low outgassing and resistance to aviation hydraulic fluid and fuel. Feedstock and print costs are very high, a 400 °C-class hot end and heated chamber are required, Z-direction strength is clearly below in-plane strength, and strong oxidizers such as concentrated sulfuric acid attack it. PEKK has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 162°C (324 °F). PEKK has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Elongation at break is 8% and the elastic modulus is 3.9 GPa (0.566 Msi).
What is PEKK used for?
- Aerospace brackets
- Air and fluid ducting
- Satellite components
- Aerospace composite tooling and structures
- Electrical insulation parts
- Implantable orthopaedic devices
- ESD-safe fixtures
Advantages
- High strength — 95 MPa (13.8 ksi), better than 93% of polymer grades
- High service temperature — 240°C (464 °F), better than 92% of polymer grades
- Good corrosion resistance — 92/100, better than 91% of polymer grades
- Stiff — 3.9 GPa (0.566 Msi), better than 86% 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 — 18 kg CO₂/kg, worse than 99% of polymer grades
PEKK properties
Typical room-temperature values in the Unfilled condition; bars are the position among polymer grades.
Physical5
PEKK has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 162°C (324 °F).
Mechanical16
PEKK has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Elongation at break is 8% and the elastic modulus is 3.9 GPa (0.566 Msi).
Thermal10
PEKK is rated for continuous service to 240°C (464 °F). It conducts heat at 0.26 W/m·K (0.15 BTU/hr·ft·°F), better than 77% of polymer grades. Thermal expansion is 48 µm/m·K (26.7 µin/in·°F).
Electrical7
PEKK is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 91% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PEKK takes about 330 MJ of energy and emits 18 kg of CO₂ — more than 99% of polymer grades. Typical recycled content is 0%.
Manufacturability7
PEKK's machinability is good (60/100, better than 51% of polymer grades); weldability good (55/100); formability fair (35/100).
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. PEKK is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PEKK
Is PEKK easy to machine?
Machines like PEEK with sharp carbide/PCD tools, high speed, light feeds and air or flood cooling; stress-relieve (annealing near 200 °C) before finish cuts to avoid distortion.
Can PEKK be welded?
Joinable by laser, ultrasonic, IR and hot-plate welding as well as PAEK-compatible epoxy adhesives after plasma or abrasive surface activation; no solvent bonding.
Can PEKK be formed, bent or molded?
Requires 340–420 °C melt, 160–230 °C tools and dry feedstock (<0.02 % moisture, 150 °C for 3–4 h); FFF needs a 400 °C-class hot end plus 130–200 °C chamber and post-print anneal for crystallinity and Z-strength.
Manufacturability
The process limits FabDigit applies to PEKK. Every PEKK part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
3D printing
| Technologies | FDM, SLS |
|---|---|
| Layer height | 50 – 300 µmdefault 100 µm |
| Minimum wall / feature | 1 / 0.5 mm |
| Build envelope | 300 × 300 × 380 mm |
| Supports | Yes |
| Anisotropy | Moderate |
PEKK 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 |
|---|---|---|
| carbon fiberCF variants only | 0 – 30 | 0 |
| glass fiberGF variants only | 0 – 40 | 0 |
| carbon nanotubeESD variant only | 0 – 5 | 0 |
| polyetherketoneketone repeat unit (from T/I isomer ratio ~60:40 to 80:20 sets Tm; unfilled default | balance |
What surface finishes work on PEKK?
Sand/bead-blast or vapour-smooth-free finishing only; no anodizing — parts can be painted or metallised after plasma treatment, and machined surfaces polish to a semi-gloss tan finish.
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
Coloring
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to PEKK in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Kepstan
- Also called
- Polyetherketoneketone
How much does PEKK cost?
PEKK is a specialty-cost polymer ($$$$$), pricier than about 100% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PEKK — frequently asked
What is PEKK used for?
PEKK is typically used for aerospace brackets, air and fluid ducting, satellite components, aerospace composite tooling and structures, electrical insulation parts and implantable orthopaedic devices. In short: space-grade performance.
What is the yield strength of PEKK?
PEKK has a typical yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Strength varies by condition: see the 8 listed tempers.
Is PEKK easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines like PEEK with sharp carbide/PCD tools, high speed, light feeds and air or flood cooling; stress-relieve (annealing near 200 °C) before finish cuts to avoid distortion.
Can PEKK be welded?
Yes — weldability is rated good (55/100). Joinable by laser, ultrasonic, IR and hot-plate welding as well as PAEK-compatible epoxy adhesives after plasma or abrasive surface activation; no solvent bonding.
What surface finishes work on PEKK?
Sand/bead-blast or vapour-smooth-free finishing only; no anodizing — parts can be painted or metallised after plasma treatment, and machined surfaces polish to a semi-gloss tan finish.
Can PEKK be formed, bent or molded?
Requires 340–420 °C melt, 160–230 °C tools and dry feedstock (<0.02 % moisture, 150 °C for 3–4 h); FFF needs a 400 °C-class hot end plus 130–200 °C chamber and post-print anneal for crystallinity and Z-strength.
What is the maximum service temperature of PEKK?
PEKK is rated for continuous use to about 240°C (464 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PEKK cost?
PEKK is a specialty-cost polymer ($$$$$), pricier than about 100% 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 PEKK?
Yes — PEKK is available for 3D printing; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- Kepstan PEKK 6000/7000/8000 series technical data and processing guide — Arkema (2022)
- Antero 800NA and Antero 840CN03 PEKK FDM material datasheets — Stratasys (2023)
- Engineering Plastics — polyaryletherketone property overview — ASM International (2000)
- CAMPUS / UL Prospector PAEK property listings — CWFG / UL Solutions (2024)
- ISO 10993 series (biological evaluation of medical devices) — ISO (2018)
- EOS HT-23 (PEKK-CF) — Technical Data Sheet — EOS
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.