New Design “Duplo-headstock”

Abstract

The quality of machine tools is critical in determining their productivity and the accuracy of the finished work piece. The headstock of the machine tool has the greatest impact on these parameters. The tool or work-piece holder must meet specific demands for maximum speed and rigidity. These two parameters are variable, but always in contradiction, and depend mainly on the Spindle-Bearings System (SBS). In this context, SBS are increasingly being produced in combination with roller bearings, and with various combinations of radial ball bearings. This is mainly because the radial ball bearings allow groupings of different combinations to achieve the optimal compromise between the required maximum speed and the desired stiffness of the SBS. Stiffness, especially in ball bearings, is not constant but dependent on the magnitude of the load. The SBS is a statically indeterminate system, and an accurate calculation of the bearings and its nodes, as well as the whole system, is only possible using iterative methods. The exact calculation of SBS stiffness cannot be achieved without the use of powerful computers and high-quality software. Selection of the optimal configuration is achieved by analyzing a number of potential, alternative SBS solutions. The exact calculation of a large number of variants, and manufacturing their prototypes, is time consuming and very expensive. The solution is to quickly determine, with sufficient reliability, the parameters of the bearing nodes, which are influenced by the radial ball bearings. It is only in the final variation that an accurate calculation using iterative methods can be made, followed by subsequent production of a prototype for verification. At our workplace, we dedicate our time to intensive research into bearing nodes and the complete SBS.