Guide to Selecting Machine Tool Rotary Table Bearings: Analysis of Advantages and Disadvantages of Different Types

In CNC machining, rotary tables are widely used in various machine tools such as milling machines, boring machines, vertical lathes, and vertical milling machines. To ensure the rotary table can support the weight of the workpiece while maintaining high rotational precision, selecting the appropriate bearings is critical. Below are some common types of rotary table bearings and their characteristics:

Hydrostatic Bearings

Hydrostatic bearings achieve lubrication for sliding bearings by establishing a hydrostatic load oil film on the bearing surface through externally supplied pressurized oil. These bearings operate under continuous lubrication from startup to shutdown, resulting in minimal wear, extended service life, and low starting power requirements. Additionally, hydrostatic bearings offer high rotational accuracy, substantial oil film stiffness, and effective suppression of oil film oscillation. They are suitable for components subjected to high axial forces, with turntable diameters exceeding 10 meters. However, hydrostatic bearings require a dedicated oil supply system for pressurized oil, entailing more complex maintenance and higher costs.

Thrust Ball Bearings

Thrust ball bearings can withstand certain axial forces and are primarily used to support the weight of workpieces. Cylindrical roller bearings, on the other hand, are mainly employed for radial positioning and bearing external radial forces. This design is widely used in the rotary tables of small to medium-sized machine tools and is relatively inexpensive. However, thrust balls have limited axial load capacity and present challenges in lubrication.

Crossed Roller Bearings

Crossed roller bearings are widely used in rotary tables. They feature two raceways with two rows of crossed rollers. Compared to traditional thrust bearing-radial bearing combinations, the cross roller bearing offers a more compact structure and smaller footprint, simplifying turntable design and reducing costs. Optimized preload ensures high rigidity, guaranteeing the turntable's structural stiffness and precision. The dual-row cross roller design significantly increases the bearing span, delivering exceptional resistance to overturning moments.

Selecting the appropriate rotary table bearing is critical to ensuring efficient machine tool operation. Choosing the right bearing type based on workpiece weight, rotary table dimensions, and precision requirements is key to enhancing machine tool performance.

For further information, please contact:

Sundy Liu ; sundyliu@lzjmbearing.com