Tech Talks

5 Reasons to replace PTFE-lined bearings Many times, high-performance plastic bearings are confused with PTFE-lined metal-backed bearings, which are a much older technology. Over the past 3 decades, there has been a revolution in the advancement and use of highly engineered plastics in bearing applications. Plastic bearings are now designed to stand up to high speeds and loads, temperature extremes, caustic chemicals, and a wide range of other application requirements and environmental factors. In this tech talk, uncover the top 5 reasons for replacing PTFE-lined bearings with engineered plastic options. 1. Thicker wear surface A PTFE-lined bearing is comprised of a metal shell and a very thin coating of polytetrafluoroethylene, or PTFE, applied to the inside as the wear surface of the bearing. These types of bearings typically have a maximum wear surface of 0.025 mm, or about 0.001 inches. As the PTFE lining is stripped or worn off during operation, the metal shell becomes exposed, creating a metal on metal effect between the bearing and the shaft; this can cause serious shaft damage, or seizing of the bearing. This issue is most common when bearings are used in oscillating applications, or where high edge loads are present. In comparison, engineered plastic bearings are comprised of advanced polymer compounds, which contain particles of solid lubricant embedded in millions of tiny chambers throughout the entirety of the material. During operation, these particles of solid lubricant are transferred onto the shaft to help lower the coefficient of friction and rate of wear, and eliminate the risk of metal on metal contact. This allows the acceptable amount of wear to be determined by the type of application, unlike PTFE-lined alternatives which will fail if the wear exceeds the 0.025 mm lining's thickness. 2. Resistance to corrosion and chemicals The metal shell of a PTFE-lined bearing becomes problematic in applications where water or chemicals are present. In these types of environments, metal rusts, corrodes, and contaminates sensitive areas, while also leading to bearing failure. Bearings made entirely of plastic are impervious to rust, and highly engineered materials are available to resist chemicals, oils, and other caustic media. The trend towards using biofuels has created new issues for PTFE-lined bearings. Biodiesels and other biofuels have a tendency to absorb a high level of moisture, which can greatly effect metal bearings. After limited exposure to moisture, parts of the metal bearing shell can peel away from the PTFE lining. To combat this problem, plastic bearing materials have been developed to be used specifically in biofuel or other high-moisture applications. PTFE-lined metal backed bearing compared to igus ® iglide ® J bearing

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