PEEK Parts: Description and Uses

PEEK, also known as polyetheretherketone, is a high performance, engineering plastic. It is a semi-crystalline, high temperature resistant thermoplastic. It is one of the most popular materials we manufacture parts from here at Craftech®. PEEK has a strong following in the aerospace and semiconductor industries. In this article, we will describe some of the excellent properties that make this plastic material so popular.

Mechanical Properties

Custom PEEK partsThe processing conditions used to mold PEEK can influence its crystallinity and mechanical properties. The Young’s modulus is 3.6 GPa and its tensile strength is 90 to 100 Mpa. With its resistance to hydrolysis it does not absorb water.  Therefore it is highly tolerant to thermal degradation as well as attacks by both organic and aqueous environments. It is susceptible to halogens and strong Bronsted and Lewis acids as well as some halogenated compounds and aliphatic hydrocarbons at high temperatures. It is soluble in concentrated sulfuric acid at room temperature. The material also has superior creep resistance and also is a high strength alternative to fluoropolymers


Some grades have a continuous operating temperature of up to 250 °C (482 °F). PEEK has a glass transition temperature of 143 °C (289 °F) and melts at 343 °C (662 °F.)  It is highly resistant to thermal degradation as well as to both organic and aqueous environments.  PEEK has a UL flammability rating of V-0 and exhibits low smoke and toxic-gas emissions. It resists radiation and a wide range of solvents. It can withstand boiling water and the superheated steam used with autoclave and sterilization equipment at temperatures higher than 482°F.

Several Grades of PEEK are Commercially Available

Unfilled PEEK

The unfilled grade offers the highest elongation and toughness of all the grades of peek. It is available in light brown or tan and black. All unfilled PEEK grades comply with FDA regulation 21 CFR 177.2415 for food contact.

Glass fibers magnified through a microscopePEEK 30% glass filled
includes glass fibers as an additive. Therefore, it is ideal for structural applications that require improved strength, stiffness or stability at temperatures of about 300°F (150°C). This grade dramatically lowers the material’s expansion rate and increases its flexural modulus. Glass-filled PEEK is light brown or tan in color.

PEEK 30% carbon filled uses carbon fibers as an additive. The carbon fibers enhance the compressive strength and stiffness of the material and dramatically lowers its expansion rate.  This plastic material grade offers optimum wear resistance as well as excellent load carrying capability. Peek 30% carbon filled provides 3 ½ times higher thermal conductivity than the unfilled grade.  Therefore, it dissipates heat from the bearing service faster. Peek 30% carbon filled is black in color.

PEEK (Bearing Grade, Ketron HPV™) is a grade that is reinforced with graphite, PTFE and carbon fibers. Therefore it offers the lowest coefficient of friction and the best machinability of all the PEEK grades. The bearing grade, Ketron HPV,™ sports an excellent combination of low friction, low wear, high limiting PV, low mating part wear and easy machining. This grade is black or dark gray in color.

Other Uses for PEEK

PEEK is often used in automobiles, the marine industry, the nuclear industry, oil-wells, electronics and aerospace industries. PEEK  is considered an advanced biomaterial and medical implants are made from it. Therefore, it is increasingly used in spinal fusion devices and reinforcing rods. Because of its robustness items in demanding applications are made from PEEK. Some of these parts include bearings, piston parts, pumps, compressor plate valves and cable insulation.

Craftech is experienced in supplying polyetherertherketone parts to many customers with extreme demands.  If you have one, please contact us.

Questions? Comments? Let me know in the comments section below.

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