Linear Motion Control - 2011-09-28
For high-performance drive systems in machine tools
The machine tool industry is placing ever-increasing demands on linear drive systems in regards to traverse rates, precision, and quiet running. NSK is responding to this trend – with the new HMS series of ball screws, which has been presented at the EMO trade fair.
The machine tool industry often expects high traverse rates, which can best be achieved by using drives with a large lead. At the same time, a high level of precision and accurate positioning is needed, which are best attained by selecting a small lead.
NSK has now succeeded in delivering both: the new HMS series consists of high-speed ball screws that can achieve a maximum dn of 160,000. The newly developed ball recirculation system makes a significant contribution towards this. The ball screws also achieve high precision levels and exceptionally low noise levels. The HMS series is therefore ideal for low-noise, high-performance machine tools.
In practice, the improved design reduces the noise level by more than 6 db(A). The human ear perceives this as a reduction of almost 50% compared to the original volume. The frequency range of the noise is also subjectively considered to be easier on the ear. Another important factor is the rigidity, which is significantly higher than that of comparable ball screws from this performance class.
HMS ball screws are available with spindle diameters of 40, 45 and 50 mm and leads of 8 (ø 45), 10 (ø 40, 50) and 12 mm (ø 40, 50). Machine manufacturers also have a choice of cooling system: either conventional spindle cooling via a hollow shaft or the integrated nut cooling mechanism developed by NSK in 2010. This new cooling system is more cost-effective and also performs better than conventional cooling because the drive is only cooled at the specific points where high temperatures arise due to friction. Two HMS systems can also be connected to create a high-precision tandem drive system.
With these features, NSK HMS ball screws are ideal for use in precision and high-speed machine tools.