Linear Guidance Systems Ensure Accuracy and Reliability of DMG Milling Centres

In the machine tool industry, system partnerships and co-development projects between OEMs and component suppliers are now increasingly important. Machine tool manufacturers prefer to focus on their core competence, whilst sourcing ready-to-fit components and sub-systems from high performance technology partners. The result is that all parties involved benefit from this close cooperation, including the manufacturers, component suppliers and end users.

German machine tool manufacturer DECKEL MAHO GILDEMEISTER (DMG) for example, is working closely with The Schaeffler Group's INA Linear Technology division on a number of new machine tool developments.

When it comes to linear guidance systems for its large and super-sized milling centres, DMG relies exclusively on Schaeffler's high performance RUE-E linear recirculating roller bearing and guideway assemblies.

The RUE-E linear guidance system provides smooth, uniform running characteristics and high dynamics, ideal for precision linear movement of heavy loads. The range is modular and so customers can select from a range of accessories to suit their application.

The range also benefits from Schaeffler's patented injection moulding technology, which enables perfect rolling element guidance in the load and return zones, optimised transitions and the best possible running characteristics with very low stroke pulsation. Schaeffler has also reduced the number of components in the design, resulting in more robust, reliable rolling element guidance.

Labyrinth seals on the rolling element recirculation system improve protection against contamination. Uniform lubrication is also guaranteed due to a completely closed and sealed lubrication duct.

The design of the guides also incorporates an efficient sealing concept, comprising standard seals: single lip upper seals, double lip lower sealing strips, as well as double lip end wipers. The end plates fitted as standard in front of the contact end wipers provide extra protection against coarse contaminants, which means the contact end wipers retain their full performance capability even in environments with fine, often aggressive contaminants.

DMG has been working with Schaeffler to develop linear guidance systems for its DMU/DMC 200 to 340 milling centres, including 5-axis machining centres. Depending on the size of the machine tool and the loads acting on the main axes, linear recirculating roller bearing and guideway assemblies in sizes RUE 35, 45, 55 and 65 are specified. In addition, in order to meet specific customer requirements, DMG uses covering strips; double lip wipers and customised sealing kits from Schaeffler's modular KIT system. These are pre-assembled at the factory. Load calculations are carried out using Schaeffler's BEARINX® calculation software, complemented by DMG's own design calculations for further system refinements.

Optimised distribution of lubricant for the RUE-E units ensures minimal flow grease consumption of just one litre per year using machine lubrication intervals of four hours. Additional components are not required.

Due to extremely high axial loads on the milling centres, Schaeffler supplies DMG with selected combinations of guideways and recirculating roller bearing units. These precisely matched pairs are combined to achieve minimal 'waviness' in the guideways and maximum accuracy of the carriages. All key data is recorded in test documents.

The RUE-E units are supplied fully assembled and well protected in special returnable containers, which prevent the risk of damage or product mix-ups. Prior to installation, DMG inspects the machine parts on which the linear roller bearing and guideway assemblies are to be installed with extreme accuracy, examining them for compatibility with the linear guides.

The partnership between DMG and Schaeffler is not limited to linear technology. Under its INA, FAG and IDAM brands, Schaeffler offers a comprehensive range of products for every conceivable bearing location on a machine tool, including drive technology, bearings for main spindles and feed spindles, as well as all rotary axes systems.

For more information on Schaeffler's range of linear guidance systems for machine tools, please call the Marketing Department on 0121 313 5870 or email

With a total of 65,000 employees at over 180 locations around the globe and group sales of 7.3 billion Euros (fiscal year 2009), the Schaeffler Group is one of the world's leading rolling bearing manufacturers and automotive component suppliers. The corporate group includes the INA Group with headquarters in Herzogenaurach, the FAG Group based in Schweinfurt as well as the LuK Group, with headquarters in Bühl.

Dean Palmer
SilverBullet PR Ltd
Tel: 01780 753 000
Mobile: 07703 023 771

Schaeffler (UK) Ltd,
Forge Lane
Sutton Coldfield
West Midlands B76 1AP
Tel: 0121 313 5870
Fax: 0121 351 7686

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