Bearing and Wear Application (i.e., frictional forces)
Structural (static or dynamic) Application
Determining the primary function of the finished component will direct you to a group of materials. For example, crystalline materials (i.e., nylon, acetal) outperform amorphous materials (i.e., polysulfone, Ultem* PEI or polycarbonate) in bearing and wear applications. Within the material groups, you can further reduce your choices by knowing what additives are best suited to your application.
Wear properties are enhanced by MoS2, graphite, carbon fiber and polymeric lubricants (i.e., PTFE, waxes).
Structural properties are enhanced by glass fiber and carbon fiber.
Once you have determined the nature of the application (B&W or Structural), you can further reduce your material choices by determining the application's mechanical property requirements. For bearing and wear applications, the first consideration is wear performance expressed in PV and"k" -factor. Calculate the PV (pressure (psi) x velocity (fpm)) required. Using Figure 1, select materials whose limiting PV's are above the PV you have calculated for the application. Further selection can be made by noting the "k" wear factor of your material choices. In general the lower the "k" factor, the longer the wear life of the material.