Centreless grinder uses NSK RA high-precision roller guides
08 April 2021
THE NEW Tschudin Cube 350 centreless grinding machine is using NSK’s RA series of low-friction, high-rigidity roller guides, where they are helping to generate excellent levels of surface finish on machined workpieces.
Tschudin’s Cube 350 operates using the centreless cylindrical grinding method and, thanks to design innovation, benefits from the potential to install several machines side-by-side. In addition to its high-precision capability, the machine facilitates very short set-up times for product changeovers, thus enabling the economic machining of small component batch sizes.
The drive design has a major impact on the performance of this precision grinding machine. Deploying linear drives in three axes (X-axis/control wheel adjustment, U-axis/grinding wheel adjustment and W-axis/workpiece adjustment) lays the foundation for obtaining both high productivity and flexibility.
All drives must operate with micron-level accuracy. In the case of linear drives, this ethos also applies to the guide elements. As a result, Tschudin has been using linear guides from NSK's RA series in its centreless cylindrical grinding machines for many years. Thanks to their proven reliability, these high-performance products are now also demonstrating their worth in the Cube 350.
RA series roller guides offer high maximum load capacity and exceptional rigidity, therefore delivering the traverse and repeat accuracy necessary in machine tools such as the Cube 350. Moreover, these capabilities are particularly desirable in applications that require superior surface finishes.
With the RA series, expert design engineers from NSK have succeeded in satisfying the conflicting objectives of extreme rigidity and very smooth, low-friction movement. The RA guideways run with high precision and low vibration, while at the same time meeting the toughest rigidity requirements.
Rigidity is always a key factor in centreless grinding, where pressure and counter-pressure constantly exert on the workpiece, the grinding wheel and the regulating/control wheel. The RA guideways absorb these permanent forces to deliver outstanding traverse and repeat accuracy, as well as a prolonged service life.
This capability results from, among other things, specially designed restraining and deflecting components, as well as the use of rollers with the largest possible diameter and a slightly crowned surface to minimise vibration during rotation. The carefully matched spacing and restraint technology of the roller bodies also produces very high uniformity of the displacement forces that occur.
Thanks to these design characteristics, RA roller guides have been able to prove their quality in machine tools from leading international manufacturers, including Tschudin and its new Cube 350 series of centreless grinders.