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PEEK (polyetheretherketone) is a semi-crystalline aromatic thermoplastic with a glass transition temperature around 143 °C and a melting point near 343 °C, and it can run continuously at service temperatures up to roughly 250 °C. Just as important, it resists hydrolysis in hot water and steam, shrugs off ionizing radiation, and is chemically inert toward the gases used in low-temperature sterilization. Heat, radiation and reactive chemicals are exactly the three stresses that sterilization applies, which is why PEEK outlasts commodity plastics like polycarbonate, ABS or acetal in reusable medical devices.
Saturated steam under pressure, typically 121–134 °C for 15–30 minutes, is the most common sterilization method in hospitals. PEEK tolerates repeated autoclave cycles without meaningful loss of tensile strength, stiffness or dimensional accuracy, so it is the standard choice for reusable surgical instruments, retractors, handles and dental components that see the autoclave after every procedure. Two practical notes for machined parts: first, thin walls and long slender features should be machined from properly annealed stock, because residual stress from machining can relax during thermal cycling and show up as warpage; second, deep blind holes and assembled crevices need to be designed so steam can actually reach every surface.
Gamma sterilization uses a Cobalt-60 source, usually at a dose around 25 kGy, and it penetrates sealed packaging at room temperature. That makes it the workhorse for single-use, sterile-packaged PEEK components such as implant trials, spacers and disposable instrument parts. PEEK's aromatic molecular structure dissipates radiation energy efficiently, so mechanical properties change very little at standard doses. The main side effect is slight yellowing, which is cosmetic rather than functional, but it is worth flagging if your part has appearance requirements. Validation typically follows ISO 11137, and your machining supplier should provide lot traceability so the sterilization records line up with production batches.
EtO sterilization runs at low temperatures, roughly 50–60 °C, in a humidified gas chamber. Because there is no high heat and no radiation, it suits PEEK parts bonded to heat-sensitive components such as electronics, adhesives or thin films, and the gas penetrates long narrow lumens that steam struggles to reach. PEEK's chemical inertness means it does not react with the gas, though the cycle is slow: exposure takes hours, and the parts then need aeration to clear residual EtO before release. Validation is governed by ISO 11135. If your device mixes PEEK with temperature-sensitive materials, EtO is often the only practical route, so plan for its longer turnaround in your supply chain.
Hydrogen peroxide gas plasma systems sterilize at low temperature in about an hour and leave no toxic residue, and PEEK is fully compatible with the process. The limitation is penetration: the plasma acts on exposed surfaces, so long internal channels or assembled joints may not be reliably sterilized. Electron beam (e-beam) sterilization delivers a radiation dose in seconds rather than the hours gamma needs, and PEEK handles it equally well; it is a strong option for high-volume single-use parts where throughput matters. Dry heat, which requires 160–180 °C for extended periods, is technically feasible for PEEK but slow and rarely the first choice for medical devices.
Whatever you choose, lock the method in during design. Sterilization affects material selection, wall thickness, joint design and packaging, and changing the route late in development usually means re-validation.
Sterilization validation assumes the part itself is clean and stable, and that is where machining quality quietly decides the outcome. Burrs, torn edges and rough surfaces give bioburden places to hide and can shield microorganisms from steam or gas. Residual stress from aggressive machining relaxes during autoclave cycles and shows up as dimensional drift. And inconsistent stock material makes validation results hard to repeat from lot to lot. A shop that machines peek cnc machining for medical parts properly will use annealed, certified PEEK stock, control heat during cutting, deburr and clean parts thoroughly, and hold the tolerances your validation was built on.
PEEK gives medical designers an unusual freedom: almost every mainstream sterilization method is on the table. Steam suits reusable instruments, gamma and e-beam suit packaged single-use parts, EtO suits sensitive assemblies, and hydrogen peroxide plasma covers fast surface sterilization. The remaining variable is the quality of the machined part itself. ANOK Precision Manufacturing, an ISO 9001:2015 certified factory in Shenzhen founded in 2007, machines medical-grade PEEK alongside titanium and 316L stainless steel, holding tolerances down to ±0.002 mm and surface finishes down to Ra 0.2, including delicate work such as endoscope tubes with 0.2 mm inner diameters. If you are developing a sterilizable PEEK component, send your drawing to a medical cnc machining team that understands both the material and the sterilization requirements behind it, and get a DFM review before you cut the first chip.