Perhaps. But there are many factors to consider when replacing the bearings on a machine tool spindle. Whether the balls are ceramic or steel is not necessary the most important component. Also, it is important to keep in mind that while ceramic bearings are typically rated for 20% higher speeds, they also have lower load capacity.

When our technicians calculate maximum operating speed they consult design specifications provided by the bearing manufacturers. These specifications will include several considerations and they all factor into the speed algorithm.

The preload affects spindle stiffness as well as maximum operating speed.

Various configurations affect spindle stiffness as well as operating speed. Are the bearings mounted back to back? Is there a tandem component?

Each bearing assembly will have a different speed rating for the type of lubrication used, e.g., grease, oil mist, injection, etc.

Ball Size
Smaller balls have less mass so they can spin faster. But they are not available in all configurations. Big balls can handle more load.

Thermal Transfer Coefficient
All bearing generate heat when turning. How much heat will they generate and how fast can that heat be dissipated through the spindle housing.

Like so many things in life there is no free lunch. So when a spindle repair house promises you 20% higher speed by slapping in a pair of ceramic bearings you may want to ask what the trade off is. Will my spindle fail sooner? Can I live with the reduced load capacity? And ceramics are always more expensive.

If your spindle load is light to moderate and increased speed will provide increased production and profit, ceramics may be a good idea. However, make sure your spindle repair house does their homework before they promise you 20% higher speeds.

At HST we will be happy to change out your steel ball bearings for ceramic. But before we do, we’ll make sure the homework’s done.