Knife edge roller: fail-safe around the world

Profile

• What was needed: a knife edge roller made of the specifically developed material iglidur P210
• Requirements: high performance (20 packages per minute); reliability during use around the clock; resistance despite sugar particles, sand, dust and moisture in the system as well as temperatures of up to 100°C
• Industry: packaging branch, beverage sector
• Success for the customer: the iglidur knife edge rollers are used around the world in Krones systems and work without failure. They operate reliably, wear is hardly noticeable. In addition, they are easy to assemble, and the customer does not need to laboriously maintain them.

Problem

Regarding Variopac Pro, a fully automatic all-rounder packaging system, Krones faced a problem in 2005: the system's performance had to be increased by 20 packages per minute. Hence, there was an urgent need for action during the deflection of the conveyor belts. Originally, metal rollers with needle roller bearings were used here; however, they couldn't fulfil the higher performance requirements and were cost-intensive.
But there were further challenges. Variopac Pro packages tins and glass or PET bottles in sizes of 0.2 to 5 litres with cardboard and/or foil. The system operates around the clock and subjects the components to a lot of stress. Furthermore, sugar particles can be found in the surroundings due to production, which have a similar effect to sandpaper on the components. And all this at conveyor belt speeds of up to 0.9m/s. Dust, sand and moisture are also part of business as usual at Variopac Pro's application locations. But that is not all. At the system's shrink tunnel, conveyor belts are continuously exposed to temperatures of up to 100°C. Despite these environmental conditions and the performance requirements, the new solution for guiding the conveyor belts should have a service life of at least one year. The problem: at that time, there was no product that fulfilled these performance requirements.

Solution

To reach the desired result together with Krones AG, various different approaches were tested in the igus test laboratory before they were used in Variopac Pro. The result: an injection-moulded solid plastic roller, made of a material specifically developed for this application. The best test results were achieved with the material iglidur P210. The iglidur knife edge roller is characterised by its high wear resistance, a low coefficient of friction and resulting low drive power of the conveyor belts. Just like all iglidur materials, this one is suitable for maintenance-free and lubrication-free operations. As it can also be used in a variety of applications, this material fulfilled all requirements. When it was clear that knife edge rollers made of iglidur P210 exceeded the required service life of one year by far, Krones decided to install them in Variopac Pro. It was a great success. According to Krones, the systems - which are used across the globe, work without failure. The iglidur knife edge rollers operate reliably, wear is hardly noticeable. In addition, they are easy to assemble, and the customer does not need to laboriously maintain them. Krones is now installing iglidur knife edge rollers in Variopac Pro wherever there is a transition between two conveyor belts or plastic modular chains. As the diameters of the knife edge rollers are small, conveyor belts and modular chains can be guided very closely, which results in the gap between two belts being very small. Even if the system operates at low speed, iglidur knife edge rollers prevent the packages from tipping.