June 2019

73 www.drivesncontrols.com June 2019 BRAKES, CLUTCHES AND COUPLINGS n Achieving cost-effective precision in packaging and labelling I n packaging and labelling machinery, maintaining precision and product positioning is extremely important for high-quality results, writes Mathieu Ruault, sales director at Warner Electric . But achieving this does not necessarily require the latest servomotor technologies. Wrap-spring clutches and brakes offer a simple and cost- effective means of providing accurate, non-accumulative error indexing and positioning. Furthermore, for their physical size, these clutches can transmit considerable amounts of static torque. The most common applications involve multiple starts and stops within a revolution – such as printing presses, conveyors and packaging machines. Operating continuously, these machines rely on the product position being exactly the same week after week, without needing compensating actions or adjustments. Wrap-spring clutches can deliver not only accuracy and repeatability, but also reliability and lower running costs. However, they are not a panacea and each application should be assessed carefully to determine the most effective technologies. Machine-builders and end-users can both benefit from making the most appropriate choices when it comes to building and installing a new machinery. The initial costs of using the latest technologies are much higher and will directly affect the price of the new equipment. By contrast, given the right operational parameters, a simpler approach can deliver significant cost savings as well as much easier maintenance routines. Once a machine has been installed, the customer will be responsible for carrying out any repairs. Repairs to servomotors and their drive systems require skilled staff and replacement parts can be costly. By contrast, solenoid-activated wrap-spring clutches are simpler to repair or replace, and the process can be completed with minimal downtime. The maintenance costs are a fraction of those for the latest drives and controls. Processing systems that have high cycle rates – above 10 per minute, for instance – will satisfy the first step of the assessment process. From this point, it is necessary to analyse the load inertias and speeds, as well as identifying potential sources of friction that will affect cycle rates and repeatability. Industries such as packaging and labelling require the equipment that they use to be cost-effective and reliable with minimal running costs. By assessing each component used in a machine, it is possible to determine the most suitable design. n Industries such as packaging and labelling are cost-conscious and require to be cost- effective and reliable, with minimal running costs. Image: iStock