Precision Right Down to the Thousandth

Ringspann presents a new clamping clutch for the rotary/tilt tables of multiple-axis machining centers. Featuring torques of up to 2,400 Nm, the clutch can guarantee a torsion angle of max. 0.007 degrees.

di Alma Castiglioni

When it comes to mastering the three factors of power, dynamic and precision in modern multi-axis machining centres, the construction of workpiece holders and clamping elements play a key role.
In the coordinate field of milling machines and machining centres, the rotary/tilt tables or portals form the A and the C-axis.
Their function consists in enabling both a precise and quick approach of the workpiece to be processed into any angle setting. To achieve this, the positioning axes with the latest generation of rotary/tilt tables are driven by modern torque motors that can be controlled directly and with a high degree of precision. In order to keep precise angle settings during the highly precise simultaneous machining, the axes must be held – i.e. fixed.

A real standout product featuring the highest accuracy
Based on an existing clamping technology concept of Ringspann, an interdisciplinary team composed of engineers from the customer and the German company’s specialists developed, tested and finally realised a new clamping clutch featuring torques of up to 2,400 Nm, capable to guarantee a torsion angle of max. 0.007 degrees. With this level of accuracy, the new clamping clutch for rotary/tilt tables is a real standout product amongst the known fixing elements in this segment.
The clamping clutch employs clamping discs from the Ringspann range to transfer the axial force of pressure springs into a radial force and feature a specially designed deformation element. In this way, the torsionally stiff clamping of the kingpin is ensured. The clamping is then quickly released by applying hydraulic pressure to the clamping clutch. The torque motor can subsequently freely drive the axle into any other angle setting. The new clamping clutch for rotary/tilt tables is now being produced in series and further enriches Ringspann’s rich clamping technology portfolio, which includes countless other components from this segment. Among them are precision clamping fixtures for the mechanical processing of cylindrical internal and external surfaces, which are available in nine versions. With true running accuracies of ≤ 10 µm, these clamping fixtures are ideally suited for demanding tasks in machining technology.

A comprehensive range of solutions for the machine tool segment
Another highlight that Ringspann showcased at the fair was its expanding sleeve mandrel HDDS developed in 2016, which represents an economically attractive alternative to hydraulic expanding clamping tools in gearing technology and fine machining. It stands out thanks to true running accuracies of ≤ 5 µm, can take up workpieces with bores of up to tolerance class IT10 and reduces the costs for feeding and positioning technology in fully automated operation. The HHDS range has since been augmented by an additional, smaller expanding sleeve mandrel, which means that bores from diameters of 22 mm (previously 32 mm) can now also be clamped. However, Ringspann’s expertise in the machine tool segment does not involve clamping components only. The German company offers a wide selection of technical solutions for the secure operation of the main and auxiliary drives of machine tools and machining centres. Successful examples of this are the form-fit SIKUMAT® positive torque limiters and RIMOSTAT® friction torque limiters connected via friction lining. As overload protection for machine tool drives and spindles, they are ready for installation with various limit torques (0.5 – 10,000 Nm) and speed ranges (1,000 – 13,000 min-1) to choose from. As overload protection for push rods und drawbars, meanwhile, RINGSPANN’s bi-directional acting force limiters are suited for disengaging forces of 3,600 – 140,000 N.