Plastics Improve Roller and Cam Follower Performance

When designing motion systems that require rollers or cam followers, many engineers still believe that only all-metal components will fit the bill. Yet rollers and cam followers with polymer bearing surfaces have emerged as a high-performance alternative to traditional metal components. 

In heavily loaded applications, polymers can withstand enormous forces if designed properly. For example, we’ve engineered and delivered polymer rollers that can withstand continuous forces up to 8 tons.

Most applications, however, are not so heavily loaded. The primary role of the roller or cam follower is to transmit motion, rather than support hefty loads. In these applications, off-the-shelf rollers and cam followers will do a good job without the need for custom engineering.

And increasingly, these off-the-shelf products are not made entirely from metal. Instead, they are hybrid designs that consists a polymer load bearing surface over a metal roller bearing or structural hub. Sized as drop-in replacements for standard sized metal rollers, the hybrid rollers offer some compelling technical advantages thanks to their use of polymers. 

These advantages include:

• Self-lubrication. The engineering polymers best used for rollers, most notably gravity cast nylon 12, exhibit an internal lubricity that lasts for the life of the component. Bearing surfaces made from these polymers require no external lubrication between the roller and the rail, eliminating on-going maintenance costs and reducing the risk of failure.

• Improved Wear. Even with some lubrication, metal-on-metal contact can result in excessive wear and galling. Plastic rollers eliminate this wear mechanism altogether. 

• Contamination Reduction. Self-lubricated polymers eliminate two potential sources of contamination—stray lubricant and particulate from metal-on-metal contact. 

• Smooth and Quiet Operation. Unlike metals, polymers such as gravity cast nylon 12 have the ability to dampen shock and vibration. 

• Speed and Efficiency. Because they weigh about 40% less than similarly-sized metal rollers and cam followers, polymer products facilitate high-speed, energy-efficient motion.

• Environmental Tolerance. Rollers made from gravity cast nylon 12 do not swell in moisture and also tolerate chemical exposures and temperature fluctuations. 

• Cost Reduction. The true cost of cam followers and rollers has very little to do with their purchase price and everything to do with their lifecycle cost. Polymers save money over the long haul by eliminating the need for lubrication, extending maintenance intervals and eliminating metal-on-metal wear.

Our latest white paper delves into the technical advantages of gravity cast nylon-12 rollers and cam followers. It includes detailed comparisons nylon 12 with both metals and other plastics. Download it now.