PEEK (Polyether Ether Ketone)
polymersemi-crystalline high-performance aromatic thermoplastic
PolyetheretherketoneEOS PEEK HP3Evonik VESTAKEEPSolvay KetaSpireVictrex PEEK 450G (IM ref.)
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) | 140–146 °C | — |
| Max service temperature | 230–260 °C | — |
| As-built surface Ra | 11.0–22.0 µm | — |
Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.
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
Industries
medicalaerospaceindustrialelectronics
Standards & certifications
Compatible AM processes (2)
Other polymer materials
Related calculators
Extrusion WidthActual extrusion width from nozzle diameter, layer height, and flow rate multiplier. Wall perimeter count from nominal thickness. FFF/FDM design rule compliance check.FDM Infill Weight & CostPattern × density × material cost. Quick feasibility for FFF prints.RoughnessTheoretical Ra and Rz from layer thickness and surface angle (staircase effect). Upward, downward, and vertical faces. LPBF, SLS, FDM, SLA, DED. Per Grimm et al.Build Time EstimatorPer-process build time from part volume, layer count, and machine throughput. LPBF, SLS, FDM, SLA, DED, binder presets included.
Last reviewed: 2026-05-04 · v1 · Sources: eos-peek-hp3-2023, tan-2003-peek, hong-2015-peek, debroy-2018-review, ASTM-E8, ISO-52904