ntn bearings in high speed rotation, in particular the speed close to or exceeding the limits of record size of the table speed, the main should pay attention to the following(1) The use of precision bearings;(2) Analysis of the internal bearing clearance (taking into account the bearing temperature rise resulting reduction in the amount of internal clearance);(3) analysis of cage material type (for high-speed rotation, suitable for cutting copper alloy or phenolic resin cage system.