PEEK Manufacturers & Suppliers

Unfilled PEEK provides the baseline properties and the best chemical resistance and biocompatibility — it is the correct choice for medical implants (ASTM F2026), food contact, and applications where dielectric properties or radiolucency (X-ray transparency) are required. Glass-filled PEEK (typically 30% short glass fiber) raises tensile strength to approximately 22,000 psi and flexural modulus to 1.9 Mpsi, improving creep resistance under sustained load at elevated temperature while reducing the coefficient of thermal expansion significantly. Carbon-fiber-filled PEEK (30% carbon fiber) pushes tensile strength to 28,000-32,000 psi and stiffness to 2.5 Mpsi — approaching aluminum on a per-weight basis — at the cost of increased tool wear during machining and reduced ductility. The filled grades also lose the natural PEEK ivory color, making inspection of surface finish more difficult.

PEEK is one of the most sterilization-compatible engineering polymers available. It withstands repeated steam autoclave cycles at 134°C (273°F) with no measurable degradation in mechanical properties or dimensional change — most engineering plastics would warp or lose strength under these conditions. It also resists ethylene oxide (EtO), gamma irradiation up to 25 kGy, and hydrogen peroxide plasma sterilization. For implantable medical devices, unfilled PEEK complies with ISO 10993 biocompatibility requirements and ASTM F2026. Its elastic modulus of approximately 3.6 Gpsi (versus 110 Gpsi for cortical bone and 200 Gpsi for titanium) provides a closer match to bone stiffness, reducing stress shielding in spinal fusion cages and orthopedic implants — a genuine clinical advantage over metal.

PEEK's semi-crystalline structure means it contains residual stress from the molding or extrusion process that can relax and cause warpage when material is removed asymmetrically. The best practice for tight-tolerance PEEK parts is to rough machine leaving 0.020-0.030" of stock, stress-relieve by annealing at 300-350°F for 2-4 hours, then finish machine to final dimensions. Sharp, uncoated carbide or polished HSS tooling with positive rake geometry minimizes heat generation — excessive heat causes smearing rather than clean chip formation. Compressed air cooling is generally preferred over flood coolant to prevent moisture absorption during machining. Unfilled PEEK holds tolerances of ±0.001" routinely; dimensional stability after machining is better than most engineering plastics, which is a key reason it's used for precision bearing cages and semiconductor wafer carriers.