Plastic cam followers outperform metal

Engineering design is the art of compromise. Engineers typically select components by weighing criteria such as function, reliability, availability, and cost. In the case of cam followers, however, engineers generally don’t have much choice. With few options other than the brand, designers are often forced to accept costly features and operational limits.

For example, conventional metal cam followers are built for relatively high loads, and that’s overkill in light-duty applications. Rail or cam surfaces have to be hardened. And users have to provide manual or central lubrication or the bearing and rail can catastrophically fail. Yet excessive grease can contaminate surrounding products and lead to cam-follower skidding and wear.

Engineers must also consider the shock and vibration caused by metal-to-metal impact. And the potential for metal particles and grease contamination often restricts use in the growing clean-room market. Finally, the relatively low rotating speed of the needle bearings in these devices, combined with high rolling resistance and inertia, may limit their use in high-speed equipment.

Cam followers that use plastic-composite “tires” are a viable alternative to traditional designs. The iCam followers from Intech, Closter, N. J., for instance, include two roller bearings and a zinc-plated shaft, and are dimensionally interchangeable with metal followers.