With so many linear guide choices—from roller rails to plastic wheels—deciding which technology is right for your application can be difficult. On one hand, not every application requires machine tool rigidity and the ability to move a small car. But on the other hand, most applications require a guide that can withstand high duty cycles in an industrial environment.
Among the linear guide technologies is one that can stand up to most industrial applications yet is simple to install and maintain: cam roller guides. Below are five benefits that cam roller guides offer for applications ranging from consumer devices to material handling.
Because cam rollers are based on radial, rather than recirculating bearings, they can travel at higher speeds than traditional ball or roller rail guides. Cam rollers can commonly reach speeds up to 10 m/s (394 in/s). And while standard acceleration limits are 50 m/s2 (1,968.5 in/s2), even higher accelerations can often be achieved by increasing the preload of the cam wheels to avoid slipping. For applications such as pick-and-place or assembly, cam rollers offer the highest speeds of virtually any linear guide system.
Cam roller guides benefit from greatly reduced weight when compared to other linear guide options. Typical construction of a cam roller system consists of an aluminum rail with steel guide inserts and an aluminum carriage block with steel rollers. In contrast, recirculating bearing carriages and rails must be made almost entirely of steel for higher load carrying capacities, which improves rigidity but greatly affects weight. The lower weight of cam roller guides not only enables the increased acceleration limits mentioned above, but is also beneficial in highly dynamic applications, especially those with multiple axes.
Contamination that would wreak havoc on recirculating bearings is less detrimental to cam rollers, so even the harshest environments rarely call for special sealing or protective coverings. And for washdown or corrosive applications, the guide rail and carriage body can be constructed from non-corrosive materials or coated for additional protection.
While recirculating bearings live and die though proper lubrication, the radial bearings that support cam rollers are fully sealed and lubricated for life. Some manufacturers recommend a light oil or grease be applied between the cam wheels and the guide rail, but most offer lubrication ports or wipers to extend re-lubrication intervals and, in some cases, provide “lubricated for life” components.
Unlike recirculating bearings, which have a set preload usually achieved through ball selection, cam roller guides are preloaded by the user during installation. As application conditions fluctuate or components wear, preload can be further adjusted to maintain rigidity, speed, and performance. This also simplifies replacement, since adjustable preload means that bearing blocks and guide rails are interchangeable.
For recirculating bearing guide rails, error in alignment affects the preload of the bearing and causes uneven loading and premature wear. This is not the case for cam roller rails, since carriage preload is adjustable, making the mounting requirements for cam roller guides much less stringent than for recirculating bearing guide rails. In most cases, mounting a cam roller guide rail doesn’t require a reference edge, even when mounting two guide rails in parallel. And because cam roller rails are aluminum, mounting them to aluminum substructures, such as extruded profiles, does not require any special preparation or machining for flatness or straightness. This makes cam roller guides a good choice for self-assembled linear actuators.
So when should you use cam roller guides? When your applications will benefit from high speed, low weight, and the ability to withstand harsh environmental conditions. But also when you need an economical linear guide that doesn’t require significant time and cost to machine, mount, and assemble.