Another important consideration is how hard and soft particles can damage bearings and shafts. If particles get in between a bearing and its mating surface, both can suffer from increased wear. Dirt, dust and paper fibers are just some elements that can cause problems. Self-lubricating bearings can eliminate this issue because no grease or oil are on the bearing. This means dirt particles cannot penetrate as easily and damage the bearing and shaft.
There are a number of shafting materials and each can affect the wear of a bearing in different ways. Aluminum, case-hardened steel, stainless steel, and chrome-plated steel are just some of the choices. The hardness and roughness of the shaft material plays an important role. Hard chromed shafts, for example, are very hard, but also smooth.
The wear of igus® ' iglide® plastic bushings are lower on this shaft type than any other. However, because of the little surface roughness, stick-slip issues can become a problem.