Polymer bushings can be made from a variety of plastics, including Nylon, PEEK, Acetal, PPS, and Teflon. In this article, we are going to look at some fast facts about one particular type of polymer bushing: Nylon bushings. Nylon bushings are injection molded or cast, hence the term molded bushings. They are usually available as sleeved bushings of flanged bushings.
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1. Nylon Bushings: Surface Properties
Nylon bushings are self-lubricating, which means they do not require additional lubrication. This makes them essentially zero-maintenance bushings. They also have an extremely low coefficient of friction. They possess a Rockwell hardness value around 80 D, and are non-galling.
2. Nylon Bushings: Strength and Performance
The PV (pressure-velocity) rating of non-reinforced Nylon bushings is 3000 ft/min/psi. Unreinforced Nylon has a tensile strength of 12 ksi, a compressive strength of 15 ksi, and a flexural strength of around 15 ksi. In addition, they are extremely lightweight compared to their metal counterparts.
3. Nylon Bushings: Environmental Properties
The continuous operating temperature of molded nylon bearings is around 250°F. They are not well adapted to cryogenic temperatures. The coefficient of thermal expansion of Nylon is 5.5×10-5in/in/°F, which is very low and indicates that it is dimensionally stable even when subject to wide variations in temperature. With a typical moisture absorption rate ranging from 3-7% design considerations must include the hygroscopic nature of nylons.
4. Nylon Bushings: Chemical Compatibility
Nylon offers good chemical resistance against weak acids and alkalis, organic solvents, and most fuels. Some types of nylon perform very well in the presence of hydrocarbons and in alcohols. Their greatest weakness is strong acids.
Advantages of Nylon Bushings for Design Engineers
When looking for options for polymer sleeve and flanged bushings, dont overlook Nylon as a possible material. It can be injection molded to very close tolerances.
Nylon bushings are:
They are dimensionally stable, with a maximum continuous operating temperature around 250°F. They have a fairly wide chemical resistance, and have been the material of choice for countless engineers looking to reduce weight and costs while maintaining reliable performance.
Check out the Advanced EMC Technologies Polymer Bearing Comparison Charts free download.