Integrated balancing solution using laser measuring technology
Darmstadt, March 2017 – Based on its HM 5 balancing machines, Schenck RoTec has developed a unique customer solution for the process-integrated balancing and geometrical measurement of railway wheelsets and brake discs for modern high-speed trains. The balancing machine, which is equipped with a two-axis laser measuring system, is used for quality assurance at Stadler Rail Group's Competence and Technology Center in Winterthur (Switzerland). It forms part of a new assembly line for complete railway wheelsets.
To ensure that it can respond more even flexibly to market trends and customer requirements, Stadler Rail Group has spent more than two years intensifying the development and expansion of its in-house production depth. For example, a new assembly line for high-speed train wheelsets, including brake discs and transmissions, has been built at the Winterthur Competence and Technology Center. From here, the wheelsets, which weigh several tons and are designed for speeds of more than 160 km/h (100 mph), are sent ready to install and just in time to the bogie assembly line in Winterthur.
The automatic quality assurance system from Schenck RoTec performs several process steps at the same time. It measures any unbalance in the complete wheelset and also checks the axial and radial runout of the wheels and brake discs.
To produce this exceptional machine, the engineering specialist from Darmstadt, a subsidiary of the Dürr Group, converted its HM 5 universal balancing machine by integrating new measuring, control, and safety components to create an innovative complete system for measuring wheelsets and brake discs. "The consistent implementation of our customers' wishes and requirements has enabled us to create a completely new machine concept on the basis of a tried and tested horizontal balancing machine with a friction drive," said Stephan Frese, a sales engineer at Schenck RoTec.
Unique combined solution
This combined balancing and measuring station has been a key component of the wheel assembly process in Winterthur for more than six months now. It offers state-of-the-art safety technology and includes numerous adjustment systems to ensure infinitely variable adaptation to different roller carriage sizes. In order to carry the wheelsets, which can weigh up to 5,000 kg, the machine is fitted with heavy-duty bearing pedestals and roller carriage inserts. The support frame design also includes a variable frame to hold the gear transmissions mounted on the driving wheelsets. In addition, the machine has a high-precision laser measuring system that determines the axial and radial runout of the wheels and brake discs fully automatically. Its key components are two laser measuring heads that are axially and radially adjustable and which can be swiveled through 180 degrees.
The new machine takes just a few minutes to balance and geometrically measure a complete wheelset. Its high degree of automation and the multitude of adjustment possibilities also make it very flexible and user-friendly.
As soon as the system detects an unbalance, the axial and radial runout of the wheels and the axial runout of the brake discs are checked. In this process step, the wheelset is rotated very slowly while being "scanned" by the movable laser measuring heads. By performing two measurements in each case (tolerance 0.3 mm), they first determine the radial runout of the wheels and then the axial runout of the wheels and brake discs. Brake discs mounted on the outer side of the wheel are accessed with a 180-degree swivel of the heads. Once the geometrical measuring process is finished, the laser moves back to its parking position. The friction drive also retracts and the machine releases the wheelset for removal.
Stadler project manager Jürg Hofmann is more than satisfied with the new machine: "The engineering specialists from Schenck RoTec have provided us with the optimum solution for the final step in quality assurance for our new railway wheel assembly line. Without the need for external service providers, we can now determine unbalance and perform geometrical measurements on our complete wheelsets on demand and on schedule at a central location in our plant."