PEEK (Polyether Ether Ketone)

polymer

semi-crystalline high-performance aromatic thermoplastic

PolyetheretherketoneEOS PEEK HP3Evonik VESTAKEEPSolvay KetaSpireVictrex PEEK 450G (IM ref.)

PEEK (Polyether Ether Ketone) 3D printed component

Density

1.30 g/cm³

YS (SLS as-built (EOS PEEK HP3))

70–90 MPa

UTS (SLS as-built (EOS PEEK HP3))

75–96 MPa

Elongation (SLS as-built (EOS PEEK HP3))

1.5–3.5 %

Elastic modulus

3–4 GPa

Thermal conductivity

0.3 W/m·K

Glass transition (Tg)

140–146 °C

Max service temp

230–260 °C

Mechanical & thermal properties — 2 conditions

Property	SLS as-built (EOS PEEK HP3)	FDM as-built (XY)
Elastic modulus	3–4 GPa	3–4 GPa
Yield strength (0.2%)	70–90 MPa	75–105 MPa
Ultimate tensile strength	75–96 MPa	80–110 MPa
Elongation at break	1.5–3.5 %	1.5–4.0 %
Density	1.26–1.33 g/cm³	—
Thermal conductivity	0.3 W/m·K	—
Glass transition (Tg)

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Engineering considerations

Crystallinity optimisation: post-print annealing at 200°C/1–2h in inert atmosphere increases crystallinity from 20–25% to 25–30%, improving modulus ~10% and fatigue resistance. Standard practice for medical-grade PEEK parts.
Implant qualification: for implantable PEEK devices, use Evonik VESTAKEEP i4 3DF (implantable grade) or equivalent. Requires ISO 10993-1 full biocompatibility testing battery. ASTM F2026 covers PEEK for surgical implants — verify AM PEEK compliance.
Radiolucency advantage: PEEK X-ray attenuation coefficient is close to human bone — allows clear post-operative imaging without metal artefacts. Critical for spinal cage placement verification and fracture plate monitoring.
FDM vs SLS PEEK selection: if near-isotropic properties are required, use SLS PEEK (EOS HP3). If the build orientation can be controlled so the primary load axis is in XY, FDM PEEK is more accessible and still achieves high performance.
Surface finish for implants: as-built PEEK SLS (Ra ~16 µm) must be machined and polished for bone-contacting surfaces. Surface modification (plasma treatment, hydroxyapatite coating) required for osseointegration in load-bearing implants.
Chemical resistance note: PEEK dissolves slowly in concentrated sulphuric acid (H₂SO₄ >98%). Avoid immersion in concentrated H₂SO₄ for extended periods. Resistant to all other strong acids and bases at room temperature.
Thermal cycling: PEEK has lower CTE (47 µm/m·K) than metals — in metal-composite assemblies, differential thermal expansion can generate interfacial stress during sterilisation cycles. Design snap-fit or bonded interfaces with clearance to accommodate CTE mismatch.
Alternative high-performance polymers: if PEEK properties are not required at the cost level, consider SLS PA12 (60–80°C max), SLS PEBA/TPU (flex + temp), or FDM ULTEM 9085 (FAA FST certified, ~170°C HDT). Only specify PEEK where its unique properties justify the cost.

Advantages

Highest continuous service temperature of any standard AM polymer: 250°C — unmatched by PA, PC, or POM
Biocompatible and radiolucent — ideal for spinal and orthopaedic implants where post-op imaging is required
UL94 V-0 flame retardance without additives — suitable for aerospace interior components
Excellent chemical resistance: virtually inert to all organic solvents, strong acids (except concentrated H₂SO₄), and hydrocarbons
Good tribological properties — low friction coefficient (~0.35 vs. steel); suitable for gears and bearings
Autoclave sterilisable: survives 134°C saturated steam cycles — critical for reusable surgical instruments
Near-isotropic in SLS — avoids the severe Z-direction weakness of FDM PEEK
Inherently low outgassing — suitable for vacuum and clean-room environments

Limitations

SLS PEEK requires high-temperature systems (EOS P 800, ~380°C chamber) — not available on standard SLS machines
SLS PEEK properties are 70–80% of injection-moulded PEEK — crystallinity deficit reduces modulus and strength
FDM PEEK has severe Z-direction weakness (30–50% lower than XY) — anisotropy limits structural applications
Highest material and processing cost of any standard AM polymer — typically 5–10× more expensive per kg than PA12
Low elongation (2–3%) — PEEK SLS fails semi-brittlely; not suitable for impact-critical applications
Limited machine ecosystem: only a handful of commercial SLS systems qualify for PEEK. FDM PEEK requires dedicated high-temperature printers
SLS PEEK powder cannot be reused as effectively as PA12 — higher virgin powder requirement increases cost
Requires post-annealing (200°C/2h) to improve crystallinity for medical applications — adds process step

Typical applications

Spinal fusion cages and interbody devices (PEEK is radiolucent — allows X-ray and MRI monitoring)Trauma plates, bone screws, and cranial implantsAutoclave-sterilisable surgical instrument components (134°C, 3 bar)Aerospace interior structural parts (high-temperature, fire-resistant)Chemical resistant fluid handling componentsHigh-performance electrical connector housingsSemiconductor handling fixtures (clean-room compatible, low outgassing)High-temperature jigs and fixtures for composites processing (autoclave)Precision gears and bushings in high-temperature environmentsOil & gas downhole instrumentation housings

PEEK (Polyether Ether Ketone)

Mechanical & thermal properties — 2 conditions

Engineering considerations

Advantages

Limitations

Typical applications

Industries

Standards & certifications

Compatible AM processes (2)

Other polymer materials

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