PEEK Increasingly Popular
Polymer bushings have found widespread acceptance because they are typically low friction, light weight, relatively inexpensive, have an extended service life, and can be self-lubricating. Most polymer bearings and bushings are made from a form of PEEK, PTFE, Nylon, or UHMW PE. PEEK is becoming increasingly popular because it offers a good balance of chemical, heat, and wear resistance; and is, versatile when it comes to manufacturing.
Need more information? Check out these articles on PEEK, PTFE, NYLON AND UHMW from the popular Advanced EMC Technologies Blog
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Of special interest to those working with bushing and bearings, though, are its tribological properties. As you recall, tribological properties are related to how two surfaces interact during relative motion. Some of the most critical tribological properties for bearings and bushings include the dynamic coefficient of friction, limiting PV value, and the wear factor.
For example, the limiting PV value of bearing grade PEEK is about the same as that of PTFE.
Friction results in heat, which can not only cause critical parts to heat up, but also to deform. PEEKs maximum service temperature of 482°F is comparable to that of PTFE at 500°F. If a bearing or bushing is going to be exposed to high temperatures, or to varying temperatures, then the linear coefficient of thermal expansion (CTE) should be as small as possible.
That means that bearings and bushings made of PEEK arent subject to nearly as much thermal deformation as those made of PTFE, UHMW PE, or nylon. In short, PEEK has a high maximum operating temperature combined with superior thermal stability.
As you can see in the table below, bearing grade PEEK doesnt have the lowest coefficient of dynamic friction or the lowest K factor, but offers a high limiting PV combined with superior thermal stability. It remains an excellent option when selecting a material for a bushing or bearing.