Roller type guides like RG or QR use cylindrical rollers instead of balls. Compared with ball-type HG guides of the same size, they offer:

• Much higher rigidity and load ratings (especially for moment loads)

• Better resistance to vibration and deformation in heavy cutting

They are a strong choice for very heavy cutting, high column machines, boring mills and axes where even small deflection is not acceptable.

However, there are important trade-offs you must consider:

1. Maximum speed and heat
   Roller guides have line contact and higher friction than ball guides. This means:

   • Lower maximum recommended speed

   • More heat generation at high speeds
     On very fast automation axes (high m/min), using roller guides without checking the catalog limits can cause overheating and grease breakdown.

2. Installation surface flatness
   Because roller guides have very high rigidity and very little self-alignment capability, they are more sensitive to base flatness and parallelism.

   • If the mounting surfaces are not machined accurately, the preload can become too high locally.

   • The axis may feel very heavy, wear quickly or even bind.
     With HG ball guides, minor errors are sometimes absorbed; with RG/QR you must have a better-machined base.

3. Required driving torque
   Higher friction also means higher motor torque is needed:

   • Starting torque and running torque are both higher than with HG

   • If you upgrade from HG to RG/QR without adjusting the motor and drive, you may see overload alarms or following error.

In summary, roller guides are recommended only when you clearly need very high rigidity and load capacity, and your machine can support higher base machining accuracy, lower speed or higher motor torque. For many axes, a well-selected HG series is still the more balanced and economical choice.