MOTION CONTROL for a measuring system

A custom rotary table based on a Nexen roller- pinion system has been developed to measure the roughness of a key car engine component


rom the simple caliper gauge to precision optical measuring systems,

Mahr (, which has its headquarters in Germany, is a key supplier to a range of industries – including automotive, medical technology, aviation, optics and renewable energies. Precision is often essential, so the company’s equipment is designed to deliver the highest levels of accuracy in measuring dimensions, contours and surfaces. In a recent project, the company was tasked with developing a system to measure the roughness of a key engine component for a French automotive manufacturer. So, Mahr entered into partnership with Unicum Transmission de Puissance, Nexen’s sales and marketing partner in France. To meet the requirements, the Nexen CRD350 rotary table was developed. Based on a roller-pinion system, this enables dynamic movements with an

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.” Jacques Loiseau, special developments

exceptional level of positional accuracy. Accurate to 35 arc seconds, and with a maximum speed of 94rpm and torque of 564Nm, the CRD350 is a compact drive solution without backlash that requires no maintenance or lubrication. Alain Fourcroy, sales engineer for

Unicum, explains: “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.

Custom solution from Mahr for measuring an engine component with the CRD350 compact ring drive from Nexen

manager at Mahr, added: “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 250kg with an eccentricity of 200mm. Despite the challenges, we were able to satisfy this requirement with complete success: the ability to handle heavy loads with zero backlash.” 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.

Nexen Europe Group


As well as being the longest mountain range on Earth, the Andes are the tallest outside of Asia – and pumping water 4000 vertical feet up and over the mountains is a complex task. With almost insurmountable terrain to conquer, pumping stations are placed under greater pressure to perform. Several diesel engine powered pumping stations are installed

in stages up the side of a mountain. Each pumping station contains a massive remote-mounted 34-stage centrifugal pump to provide the required final discharge pressure to move the water uphill to the next station. Every 12 cylinder diesel engine installed at the stations offers 1425 HP driven to a speed increasing gearbox with a 1:1.356 output ratio. Manual clutches, which could engage and disengage

regardless of speed, were being used, however due to the respective differential in RPM between the two shafts during engagement and disengagement, the clutches were experiencing excessive wear. This was eventually leading to total clutch failure, ceasing pumping along the entire stretch of pipeline until a new replacement could be found. With each individual pumping station housing a manual clutch, another power transmission solution was required to safeguard the continued reliability of the pipeline and its associated pump drivetrains. To overcome the problem, Stromag’s Periflex VN Disc Couplings were chosen. The Periflex VN is designed

specifically for use with diesel engines due to its simple direct flange connection to flywheels and the flexibility of disc coupling design. Torsional flexibility is built in along with linear spring characteristics, which ensures the same coupling stiffness regardless of applied torque. As diesel engines produce high torque outputs in operation, this inherent flexibility and consistency ensured a smoother transition of power to the pump. For this project, the couplings selected deliver a

maximum torque of 48,000Nm, with the high torque capacity and direct-mounted design ensuring that the clutches could be entirely eliminated from the drivetrain of each pumping station. Not only was Torsional Vibration Analysis (TVA) testing carried out to ensure the suitability of the coupling for the project, but Stromag amended the design of the coupling to ensure the Periflex was able to retro-fit within the confined spaces of the customer’s existing gearbox housing. Of additional benefit, their simple mounting caused minimal disturbance to existing equipment. With the manual clutches removed and the Periflex couplings

installed, operators were able to see an increase in operational uptime. Furthermore, with clutches no longer regularly failing, the end user was able to enjoy an increase in operational cost-effectiveness – a real benefit when running multiple pumping stations.





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