PEEK as a plain bearing: the material that withstands heat when everything else fails

PEEK withstands high temperatures, aggressive chemicals and high mechanical loads. This makes the material an attractive option for plain bearings in demanding environments. When other engineering plastics stop working, PEEK can be the solution.

Why use PEEK in high-temperature applications?

PEEK is a high-temperature plastic with a continuous operating temperature of up to 250 °C and can withstand even higher temperatures for short periods. Most engineering plastics begin to lose mechanical strength at 100–150 °C. PEEK retains both stiffness and strength even at elevated temperatures.

For plain bearings and guide rails in ovens, motors or chemical processes, PEEK may be the only engineering plastic option that can withstand both the heat and the load. It is also commonly used in the aerospace and automotive industries, where weight, temperature and durability must be combined.

PEEK also has low water absorption and good dimensional stability. This means that its dimensions remain stable even in damp or hot environments where other plastics swell or deform.

Chemical environments and wear

PEEK withstands many aggressive chemicals, including oils, solvents and certain acids. This makes the material suitable for use in the chemical industry and in process equipment where other plastics degrade.

As a sliding material, PEEK has low friction and good wear resistance. For even better sliding properties, there are filled grades containing, for example, carbon or PTFE. These variants are used for slide rails and wear rails, seals and linear guides.

Special grades are also available for applications involving high levels of radiation or steam. Choose the right filler depending on whether you prioritise thermal conductivity, low friction or higher load-bearing capacity.

Machining and cost

PEEK is more difficult to machine than PA6 or POM. It requires sharp carbide tools, low cutting speeds and effective cooling. Heat build-up during cutting is high, so without adequate cooling, the tools can wear out quickly and the surface finish may be poor.

The availability of raw materials and the machining time involved make PEEK more expensive than most other engineering plastics. It is therefore advisable to choose PEEK only when the actual operating conditions require it. At lower temperatures and in less aggressive environments, POM, PA6 or PTFE can often do the job just as well at a lower cost.

If you are unsure whether PEEK is required, start by comparing the operating temperature, chemical environment and mechanical load. When any of these factors exceed what POM, PA6 or PTFE can withstand, it is time to consider PEEK.

Design advice for PEEK plain bearings

A PEEK plain bearing requires the correct clearance and surface finish in relation to the shaft. For dry operation, the mating surface should be hard and smooth. Carbon- or PTFE-filled PEEK further reduces friction and can often be operated without lubrication.

Bear in mind thermal expansion when using a press fit. PEEK has a lower coefficient of thermal expansion than metal, so the fit may change with temperature fluctuations. Use suitable fastening methods to prevent the bearing from coming loose.

Next steps

Do you have an application where PEEK might be the right choice? Speak to our sales team, view PEEK in the materials guide or request a quote for a machined component.

Suitable for dry sliding bearings

PEEK often operates without external lubrication, which is an advantage in environments where grease and oil are undesirable. Dry operation reduces the risk of contamination and simplifies maintenance. For even lower friction, PEEK can be filled with PTFE or carbon.

When selecting a filler, you should consider the mating surface. Carbon provides low friction and good wear resistance. Glass fibre increases stiffness but may be harsher on soft metal surfaces.

Supplier selection and certification

PEEK is available in several grades and with various certifications. The aerospace industry often requires specific certificates. Approved grades are available for food contact applications. Always check that the material has the correct documentation for your industry.

Order PEEK from a supplier who can provide traceability and material certificates. This is particularly important for safety-critical applications where material defects can have serious consequences.

How to order PEEK

PEEK is a high-temperature material with a price and properties that differ significantly from standard engineering plastics. It is therefore particularly important to choose the right grade and supplier from the outset. PEEK is available both in unmodified form and filled with glass fibre or carbon fibre.

Filled grades offer higher stiffness and better dimensional stability at high temperatures. They are suitable for heavy-duty plain bearings and precision components in chemical equipment. Unfilled PEEK has better impact resistance and is suitable for medical device applications.

As PEEK is expensive, it is important to minimise waste. Order dimensions as close to the final size as possible and use cutting services if you do not have the equipment to machine the material yourself.

Summary

PEEK is the right choice when no other plastics can withstand heat, chemicals or mechanical stress. The material is suitable for plain bearings, seals and components in demanding environments.

Choose the right grade, dimensions and machining method to get the most out of the material. Please feel free to contact us for advice before placing your order.

Frequently asked questions

How does the cost of PEEK compare with other plastics? PEEK is significantly more expensive than POM, PA6 or PTFE. The cost is justified by its properties at high temperatures and in aggressive environments.

Can PEEK be turned using standard tools? Yes, but sharp carbide tools and suitable cutting parameters are required to achieve a fine surface finish.

Is PEEK available as rods, sheets and tubes? Yes, PEEK is available as semi-finished products in various dimensions and can be machined as required.