Press Release

NSK Launches Light Preload Roller Guides for RA Roller Guide Series

Ideal for liquid crystal production equipment and carrier devices

NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Norio Otsuka) has developed and is set to launch light preload roller guides for its RA Roller Guide Series, a series that is currently being applied to an increasingly diverse range of applications in many different industries.

Light Preload Roller Guides for RA Roller Guide Series

NSK's RA Roller Guide Series, which NSK developed in 2003 in response to growing demand for roller guides that offer longer life and higher rigidity, particularly for machine tools, has been extremely well received by the market.
Recent years have seen increasing calls for larger equipment with longer service life not only in the machine tool market, but also in the liquid crystal production equipment and carrier device markets. Consequently, the trend is away from ball guides and towards roller guides, which offer higher load capacity. The travel distances required in the latter markets are more than seven times longer than those required for the machine tool market, and longer service life is also needed. However, liquid crystal production equipment and carrier devices do not require as high a degree of rigidity as machine tools do, as the external and fluctuating loads are not as high as those for machine tools.
Preload is applied to roller guides to enhance rigidity. The higher the preload, the higher the rigidity of the roller guide becomes. However, subjecting roller guides to an excessive preload can have an adverse impact on their service life
In response to a growing demand for longer service life in the liquid crystal production equipment and carrier device markets, NSK has developed light preload roller guides, which offer an optimized preload, to add to the RA Roller Guide Series.

NSK is set to launch this new type of roller guide in January 2010 and aims to achieve total sales worth 3 billion yen for all its roller guides by 2011. NSK exhibited this product at SEMICON Japan 2009, an exhibition that was held from December 2 through 4.

Product features

Optimized preload and longer service life

The preload that is set for this product is between one third and one half that applied to existing RA Roller Guide Series products, contributing to longer service life for liquid crystal production equipment and carrier devices.

Accurate control of a predetermined preload and rigidity together with longer service life are achieved by optimizing the contact conditions for rolling elements. This has been done by setting the internal dimensions in such a way as to minimize deformation, improving the processing accuracy for the race-way, and ensuring an even load distribution for rolling elements even with a light preload.
Smooth motion
Accurate preload control allows for an even, stable, and smooth motion.
Varied lineup
This product has a varied lineup with eight models (RA15, 20, 25, 30, 35, 45, 55 and 65) and a total of 44 varieties available.


Offering a wide range of applications, this product can be used with liquid crystal production equipment and various types of carrier devices.

Environmental friendliness

This product is friendly to the environment, as it is completely free from any environmentally hazardous materials.