Nexen ring drive for precision rotary motion control in measuring system

Wemmel, Belgium, May 2019. Compact ring drive systems from Nexen are used in industrial rotary applications where high positional accuracy and dynamic performance are required. The custom rotary indexer CRD350 was developed jointly with the metrology specialist Mahr for a French automotive manufacturer.


Headquartered in Germany, Mahr GmbH is a global manufacturer of production measuring technology and is active all over the world. From the simple caliper gauge to precision optical measuring systems, Mahr is a key supplier in a wide range of industries including the automotive industry, medical technology, aviation, optics and renewable energies. In many sectors where precision is an essential production factor, equipment from Mahr is at work, delivering supreme accuracy in measuring dimensions, contours and surfaces with the smallest possible tolerances.


Mahr received the order to develop a customer-specific system for measuring the roughness of a key engine component for a French car maker. To complete the order, Mahr entered into partnership with Unicum Transmission de Puissance, Nexen’s sales and marketing partner in France. After a preliminary study which they completed jointly, Mahr and Unicum together developed an innovative solution, the only one of its kind in Europe: the Nexen CRD350 rotary indexer. It is capable of very high positioning accuracy during rotation and remarkable dynamic output.

The rotary table is based on a roller-pinion system. It enables both dynamic movements and an exceptional level of positional accuracy. The performance parameters of the rotary table are impressive: Accurate to 35 arc seconds, maximum speed 94 rpm, maximum torque 564 Nm. Besides these advantages, the Nexen CRD350 is an exceptionally compact drive solution without backlash, requiring no maintenance or lubrication.

“The rotary table includes the Nexen roller-pinion system with a special ring gear and high-performance cross roller bearings for outstanding load capacity and rigidity. The system is mounted on a cast part. The central passthrough of the annular design allows the essential access to the middle of the table, which is extremely convenient for routing electrical wires or inserting other machine components”, explains Alain Fourcroy, sales engineer for Unicum. “The application meets the expectations of the end customer in every detail. By combining the expertise of our two companies, we have completed a project unlike any other with complete success.”

“Demand and need are at above average levels at the moment”, says Jacques Loiseau, special developments manager at Mahr. “For further developments, we want the rotary table to be able to deliver the same accuracy with eccentric loading as well. At the moment, the overhung load is about 250 kg with an eccentricity of 200 mm. Despite the challenges, we were able to satisfy this requirement with complete success: the ability to handle heavy loads with zero backlash.”

Its low structural height and generally compact design make the ring drive system extremely versatile. Apart from this customer-specific development for Mahr, Nexen CRD ring drive systems are used in a wide range of applications including cutting and gantry systems, medical devices, robots, machine tools, semiconductor production, materials handling and  aerospace.


Besides ring drive systems, Nexen produces roller pinion, linear and rotary drive systems, industrial brakes, clutches, torque limiters, overload protection devices, and control systems. The company is headquartered in the USA, with their European office based in Wemmel, Belgium. Nexen holds 120 US and international patents. The products are available from over 40 sales offices and more than 1,500 distributor outlets worldwide

About Mahr GmbH:

Mahr GmbH is headquartered in Göttingen, Germany, and specializes in production measuring technology. Besides high-performance measuring instruments for testing workpiece geometries, extremely accurate gear and metering pumps with high-precision ball guides represent a major element in the company’s product portfolio for multifunctional implementation in mechanical engineering projects. For the plastics processing industry, Mahr offers highly precise metered dispensing solutions. As an application specialist in production measuring technology, Mahr provides solutions to its customers’ metrological tasks and serves as a consulting partner in all quality-critical questions. The midsize, family-owned company has 1,900 employees and is active worldwide. Internet:

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