The Four Leading Grades of PEEK and Their Key Industrial Applications

The four most widely used grades of polyetheretherketone (PEEK) are: unfilled PEEK, 30% glass‑filled PEEK, 30% carbon‑filled PEEK, and 20% PTFE‑filled PEEK. These grades are engineered into fasteners and components such as bearings, screws, flat washers, hex nuts, gears, and medical devices, as well as a wide range of custom shapes. Below we outline the unique properties of each grade and the sectors where they excel.

Unfilled PEEK

Unfilled PEEK, the most common grade, is a semi‑crystalline polymer with a distinct melting point of 646 °F (341 °C) and a continuous service temperature of 500 °F (260 °C). It tolerates temperatures as low as –40 °C. When exposed to flame, it produces minimal smoke and toxic gas, earning a UL 94V‑0 rating. This grade withstands boiling water and superheated steam, making it ideal for medical autoclave sterilization.

Its low creep, negligible moisture absorption, and resistance to stress cracking and abrasion give it superior fatigue performance. Unfilled PEEK also shows outstanding chemical resistance to solvents, organics, salts, and bases, a trait prized in semiconductor cleanroom equipment and vacuum chambers.

With very high purity, it is FDA‑approved for repeated food contact and comes in a range of colors for aesthetic applications. Industries that rely on this grade include oil and gas, aerospace, food & beverage, marine, automotive, and nuclear, where it is used for thrust washers, bushings, valve plates, high‑load bearings, and compressor and pump components.

30% Glass‑Filled PEEK

Adding 30% glass fiber to unfilled PEEK increases strength and stiffness, making it suitable for continuous service temperatures up to about 300 °C. The trade‑off is increased wear on mating parts. Available in natural and black finishes, this grade is frequently chosen for oil and gas applications that involve steam and chemicals, where the extra mechanical robustness is required.

30% Carbon‑Filled PEEK

30% carbon‑filled PEEK enhances compressive strength and stiffness while dramatically reducing the coefficient of thermal expansion. Its superior wear resistance and load‑carrying capacity make it the preferred material for bearings that demand high thermal conductivity and efficient heat dissipation. The black finish is standard for this grade.

20% PTFE‑Filled PEEK

Often referred to as the “bearing grade,” 20% PTFE‑filled PEEK incorporates PTFE and graphite reinforcement to deliver the lowest coefficient of friction among all PEEK variants. This combination yields low wear, high load‑bearing capacity, and minimal impact on mating parts, making it a staple in bearing applications across many industries.

Craftech Industries, Inc. is a leading manufacturer of custom parts, bearings, and fasteners—including screws, hex nuts, and flat washers—across a broad spectrum of plastic materials.