“Brewery, filtration, bottling, logistics – we not only equip complete breweries, we are at home in the beverages branch all over the world,” says Jürgen Stemmer, Group Manager for Labeling Technology, Container Sets and Special Star Wheels at Krones AG, Neutraubling/Germany, one of the world’s leading suppliers of drinks bottling equipment and packaging technology. “The demand for complete solutions is increasing. We serve our customers’ complete value creation chain, from drinks production to goods distribution. “ Krones plans, develops and manufactures machines and complete lines for the fields of process technology, bottling and packaging, as well as intralogistics. Every day, millions of bottles, cans and specially-shaped containers are “processed” on lines from Krones; particularly in breweries, the soft-drinks sector and at still-wine, sparkling-wine and spirits producers, but also in the food and luxury goods sectors, as well as in the chemical, pharmaceutical and cosmetic industries.

The star wheel at Krones AG, Neutraubling, can grip glass and PET bottles of sizes differing by up to 20 mm without any problems. In a carousel, the bottles are transported to downstream machines at high speed.

There are eight lubricant and maintenance-free rollers, in each clamping unit – here is one for inspection technology. There is a PEEK rotating axis between the units which – triggered by a cam follower – ensures that the clamp opens and closes.

Star wheels for bottle inspection

Krones is a global player in this sector. “Our machines and lines offer customers economic added value all over the world,” says Jürgen Steimmer “Our aim is to find the suitable solution for every requirement.” Example: Inspection, filling and labeling technology for glass and PET bottles. Here, so-called star wheels prove their capability. They are mainly used for inspection technology. In a carousel, the bottles are transported past cameras at high speed. These cameras not only check the state and type of the individual bottles, they also detect whether they contain any soiling such as straws or cigarette stubs. Then the bottles are passed on to other areas, for example to the labeling section, via a star wheel. Such star wheels are available in four different star diameters.

The new two-component bearing developed for Krones, is a variant comprising a polymer bearing and roller. It guarantees smooth and wear-free movements on the expensive PEEK rotating axis.

Inside special plastic, outside TPU

To prepare a solution for the star whell in order to significantly lengthen its service life it was worked together. In addition, two-component rollers have been used in the spring clips for around two years now. The polymer material “iglide J” was chosen for the inner bearing. This material has been proving its worth for years in all kinds of industrial packaging and filling applications. This new two-component version proved to be the ideal solution for Krones’ requirements.It minimizes wear and guarantees even longer machine running times. Depending on the diameter, a star wheel can be made up of four, eight, twelve, eighteen or even 24 parts. is a PEEK rotating axis between the clamping units which – triggered by a cam follower – ensures that the clamp opens and closes. . “The rollers in particular used to get worn very quickly, which meant customers had to overhaul their star wheels relatively often,” Jürgen Steimmer reports. Their bottling lines were then at a standstill, the number of complaints increased. Quite often, customers had a second star wheel on hand for quick replacement in an emergency. This cost more, of course, and no-one wanted to pay these extra costs. “Something had to be done urgently. And now, we have eliminated this weakness. “

New variant comprising polymer bearing and roller

Following comprehensive tests, Krones was presented a variant comprising a polymer bearing and roller. First tests with rollers made of “iglide® J” material initially indicated that the difference in friction coefficient between inside and out was not large enough to guarantee wear-free movements on the expensive PEEK rotating axis permanently. It was only the new two-component variant with a good friction coefficient on the inside and a poor friction coefficient on the outside that brought results. The “iglide® J” inner bearing with outer sheath made of TPU rotates very smoothly and without wear on the axis, ensuring smooth operation. “We no longer get any complaints at all,” Jürgen Steimmer confirms. “The service life has been significantly extended.” “

The inner bearing is made of the tribo-optimized polymer material “iglide® J”, the outer sheath is made of TPU. Formerly orange, it is now blue with RoHS approval.