EMO 2023: Rotary Tables with Hydrostatic Bearings Offer Smooth Production

Included in the product portfolio of Hyprostatik Schönfeld, a global technology leader in the field of hydrostatic systems, are rotary tables. These are used for precision machining on lathes, milling and grinding machines, as well as on measuring machines:

The hydrostatic mounting of the rotary tables from Hyprostatik Schönfeld, offer smoother and more precise production, according to the company, thus improving product quality and saving time and money. In addition, the rotary tables are wear-free, which results in greater availability and hence improved productivity.

Hydrostatics

Many users are now opting for hydrostatic rotary tables rather than rolling bearings. The reason? Hydrostatic rotary tables are wear-free and therefore particularly low-maintenance, according to the company. At the same time, the performance characteristics always remain constant regardless of the duration of use.

"A glance at the data illustrates the benefit of hydrostatic rotary tables," a company spokesperson said. "For example, the concentricity and axial runout error for a model with a diameter of 1200 millimetres is only <0.3 µm. The runout errors for hydrostatic rotary tables are only about 10 percent of those with rolling-bearing-mounted models."

Superior Damping

Hydrostatic rotary tables are also a step ahead when it comes to damping. Their damping is several orders of magnitude higher than that achieved by roller bearing-mounted rotary tables, according to the company. By this means machine vibrations are reduced, as are workpiece shape defects. The tool life is extended, and cutting performance at the upper limits noticeably increased.

Minimal Heat Generation

Hydrostatically mounted rotary tables prove extremely thermally stable at higher speeds, according to the company. The frictional heat is generated in the oil, which is immediately transported out of the bearing, cooled externally and then returned to the bearing at a few degrees Celsius below ambient temperature. The result is a virtually cold bearing with minimum heat generation. With rolling-element bearings, by contrast, a lot of heat is generated at high speeds, heat which can only be removed from the bearing with great difficulty. This means that the thermal stability is very poor.

Precise Oil regulation

The hydrostatic elements from Hyprostatik Schönfeld work with a PM flow controller instead of with capillaries, according to the company. By this means, greater axial and radial stiffness, and also high moment stiffness, is achieved. This stiffness is obtained even with small bearing diameters; this enables higher speeds. Over and above this, the PM controller permits the use of low-viscosity oils, resulting in higher speeds or lower pump powers and less friction.

Calculation Programs for Optimum Design

Hydrostatic rotary tables ought to be optimally designed to withstand both static and dynamic stresses. For this purpose Hyprostatik Schönfeld offers specialised calculation programs for hydrostatic guides and for radial and axial bearings. These programs make it possible to define important parameters such as pocket dimensions, gap widths and pump pressure in order to achieve the required values for radial, axial and moment stiffness and, additionally, to guarantee a minimum stress reserve of up to 200%, according to the company. Likewise, the technology of the hydrostatic bearings is optimised in order to achieve the best possible vibration damping.

Rotary Tables Properties

The rotary tables feature the following:

·       Concentricity / axial runout less than 0.1 to 0.25 µm,

·       No wear, optimum damping,

·       Very stiff vis-à-vis radial, axial and moment loads,

·       Can withstand high radial and axial stresses and also moments,

·       Low heat transfer thanks to oil re-cooling, even at top speeds,

·       Exceptionally high speeds possible,

·       Wide variety of sizes, designs, speeds and load-bearing capacities as desired by the customer,

·       For swivelling axes with clamping

·       With adapted hydro unit

For more information contact:

Hyprostatik

www.hyprostatik.de

Hyprostatik at EMO 2023, EMO Hall 0O7, Booth B29

< back