Plastic Bearings mentioned
Engineers often hesitate to use Plastic Bearings in their designs, because they have trusted steel bearings for years or they just don't think plastics can handle demanding applications or environments. Plastic Bearings, however, can endure extreme temperatures, heavy loads and high speeds. Some other benefits to Plastic Bearings are listed below.
Plastic Bearings can often lead to more freedom from maintenance. Their resistance to dirt, dust and chemicals make plastic bearings a set-it-and-forget-it solution. Plastic Bearings can reduce costs up to 25%. They can be highly wear resistance, with a low coefficient of friction and can replace more expensive alternatives in many applications. Plastic Bearings also do not typically need lubrication unless steel balls are used in combination with plastic races. Plastic bearings are designed to maintain a low coefficient of friction over the life of the bearing. Compared to steel bearings, which can become pitted and increase the coefficient of friction, plastic bearings many times last longer. And finally, Plastic Bearings can be used in wash-down applications, salt water and harsh chemicals without compromising performance. Water can even be considered as a lubricant for plastic bearings.
Solid plastic plain bearings are now increasingly popular due to dry-running lubrication-free behavior. Solid polymer plain bearings are low weight, corrosion resistant, and maintenance free. After research spanning decades, an accurate calculation of the service life of polymer plain bearings is possible today. Designing with solid polymer plain bearings is complicated by the wide range, and non-linearity, of coefficient of thermal expansion. These materials can heat rapidly when used in applications outside the recommended pV limits.
Solid polymer type bearings are limited by the injection molding process. Not all shapes are possible with this process and the shapes which are possible are limited to what is considered good design practice for injection molding. Plastic bearings are subject to the same design cautions as all other plastic parts: creep, high thermal expansion, softening (increased wear/reduced life) at elevated temperature, brittle fractures at cold temperatures, swelling due to moisture absorption. While most bearing-grade plastics/polymers are designed to reduce these design cautions, they still exist and should be carefully considered before specifying a solid polymer (plastic) type.
Plastic bearings are now everywhere from photocopy machines to the tills in the supermarket. Other applications include farm equipment, textile machinery, medical devices, food and packaging machines, car seating, marine equipment and many more.
