Steel
Steel, an alloy primarily composed of carbon and iron, is the most popular material selection for linear bearings. Steel linear bearings are known to have excellent mechanical properties (i.e., high strength and rigidity); this can support heavy loads and provide smooth and precise motion. Carbon steel and stainless steel are common types of steel used in constructing steel linear bearings. Increasing the carbon content increases the hardness of steel; this affects the performance of the linear bearing.
Aluminum
Aluminum is a lightweight but high-strength metal. It is corrosion and chemical resistant. It is softer and less expensive than steel. However, aluminum linear bearings have lower load capacity than steel linear bearings. Aluminum linear bearings are also capable of providing smooth and precise motion.
Plastics
Plastic linear bearings are softer, cheaper, and have a lower coefficient of friction than metallic bearings. Typical plastics used in linear bearings are nylon, polyethylene, and PVDF, and they are usually lined with a self-lubricating coating (e.g., PTFE). They are sometimes reinforced with fibers and fillers to enhance their weight-bearing capabilities. Plastic linear bearings can be used with softer shaft materials. However, they generally have lower load capacities and are limited to room temperatures.
Bronze
Bronze is an alloy mainly composed of copper and zinc, with other additives such as manganese and phosphorus. It is a soft metal. Bronze linear bearings have a higher load capacity than plastic linear bearings. Because of the presence of metal-to-metal contact, however, they generate greater friction than plastic bearings; this necessitates maintenance of sufficient lubrication.
Ceramics
Ceramic linear bearings are typically fabricated from silicon nitride, aluminum oxide, zirconium oxide, and silicon carbide. They have high rigidity, which maintains travel accuracy and precision at high speeds. They have a high hardness, which increases their service life and abrasion resistance and reduces the generated particles from sliding of bearing components. They are also compatible with vacuum and ESD-sensitive devices and equipment.