Precision ball screws offer higher durability

Like all mechanical components, ball screws are subject to wear. One of the constant development goals of NSK´s research is to continuously reduce friction, and thus increase service life.

Before commencing development, NSK noted that typical damage patterns on the surface of ball screws can be traced back to inadequate lubrication, which leads to direct metal-to-metal contact between the shaft and nut. The shafts of precision ball screws are precision ground, and their surface texture appears under a microscope as a strip. Unfortunately, oil can easily run off these micro-strips, soon leading to inadequate lubrication.

On the basis of these findings, NSK set about developing a new surface treatment that produces a flat texture with micro-recesses. Even the smallest oil deposits can settle in these recesses and prevent inadequate lubrication, permanently and effectively. The nut thus moves constantly on an oil film, reducing wear on the ball screw, especially during slow and short strokes.

Compared with standard NSK ball screws, service life is increased by a factor of three. In addition, the new surface texture reduces break-away and stick-slip effects, even during the aforementioned slow and short movements.

The new series is suitable for use in machine tools that perform high-precision machining operations, such as milling centres for mould and die production, spark erosion machines, grinding centres, and other similarly challenging applications.