igus components make bearing points lubrication-free and durable

The KHS Group is among the world's leading manufacturers of bottling and packaging systems in the beverage and liquid-food sectors. Based in Dortmund, the system provider offers the entire spectrum of bottling and packaging technology products and services in the high-performance sector, from individual container design concept development to individual machines to complete systems including around-the-clock service. The portfolio also includes the KHS InnoPET TriBlock, which can manufacture, label and fill PET bottles. This makes production especially effective and space-saving. KHS's labeller uses various lubrication and maintenance-free igus plain bearings, ball bearings and liners.

 

Picture 1. KHS's InnoPET TriBlock stretch blow moulding/labelling/filling block (source: KHS GmbH)

 

Labeller saves material and energy

As the bottles are labelled when they are empty and then filled, the labeller requires no dryer to remove condensation from the bottles. Transport and buffer sections have also been eliminated, so the system reduces space requirements and energy consumption. Another special feature of the InnoPET TriBlock (Picture 1) is that the PET bottles are gripped above or below the support ring and transported through the labeller. Bottle holders secure the containers by the neck ring so that they are transported gently through the entire system.

 

KHS saves material for the beverage industry elsewhere as well. PET bottles are becoming increasingly lighter and thinner to save bottlers material.  The problem is that the described method of fixing of the containers during the labelling process can deform thin-walled PET bottles or fail to clamp them at all. The InnoPET TriBlock uses sterile air for neck handling and stabilisation, eliminating this risk. It can hold PET bottles for labelling without any problems. The system can process up to 82,000 bottles per hour with little energy consumption. "Now bottles can weigh very little. It is then up to the bottle design to ensure that the thin walls still provide stability," says Cornelius Adolf, Product Manager Labeling at KHS. KHS is reducing not only preform weight, but also lid height, in order to save material and reduce costs.

 

Picture 2. Upper part of the labelling module in the InnoPET TriBlock (source: igus GmbH)

 

 

Bearing points without lubrication

"InnoPET TriBlock bottle holders have three functions: They grip the bottles, stabilise them with compressed air and rotate them so that the labels can be attached," explains Andreas Ullrich, Head of Mechanical Design in the labelling technology product centre at KHS. KHS was looking for suitable plain bearings, rollers and linear bearings for the bottle holders (Picture 2). It was important to select components that do not require any grease in order rule out container contamination. So KHS decided to use igus plain bearing products. Now various iglidur J plain bearings (JSM-80-20, JFM-1618-17) are used to guide the springs, preventing them from rubbing against the shafts. The drylin R liners used (JUMO-01-20) allow a lifting movement to clamp the bottles. "Since the liners are under great stress, igus calculated their service life in advance. That way, we didn't have any problems with premature wear," says Ullrich.

 

Picture 3. Bottle holders with iglidur plain bearings, custom-made rollers with iglidur jacket and drylin liners in detail (source: igus GmbH)

 

Rollers are also used in the bottle holders, which igus manufactured especially for KHS (Picture 3). They initiate the linear movement with which the plastic bottles are clamped into the bottle holders. Other rollers were originally used here, but they caused damage. "These rollers were then fitted with a jacket made from our iglidur material and passed the test. So we equipped the rollers of the entire KHS assembly with our plastic jacket," adds Florian Blömker, igus salesman. Rollers with igus products are also used at another point. Carbon tubes into which xiros ball bearings are pressed guide the labels into the machine (Picture 4).

 

Picture 4. Lightweight deflection rollers with xiros ball bearings guide the labels into the labeller. (Source: igus GmbH)

 

Like all igus products, these bearings are maintenance-free and self-lubricating. The ball bearings also give the deflection rollers low self-locking and weight. The deflection rollers can guide up to 82,000 labels per hour into the labeller. This requires speeds of up to 16km/h.

Finally, the system uses a compact linear module with a lead screw (drylin SLW-1660) and two individual rails (drylin WSQ-16) specially made for KHS (Picture 5). They move the labelling unit, whose 600kg or so is now distributed over three points: the drylin SLW-1660, which is used for adjustment, in front, and two drylin WSQ-16 guides in the rear. As drylin linear technology moves on sliding elements made of the proven iglidur materials, it requires no maintenance or lubrication and absorbs vibration.

 

Picture 5. Station adjustment below the labeller uses drylin linear technology (source: igus GmbH)

 

Practical test passed

Ullrich gained an initial overview of the igus products online before using them. "All important technical information is available directly on the igus website, and that is very helpful. Some manufacturers make you send a query," he says. Subsequent consultation with igus identified the right plain bearings and liners quickly. When the time came to assemble the components, the igus plain bearings proved especially robust. "Price was also an important factor for us. Non-ferrous metal bearings just can't keep up." The other igus products have already proven themselves in practical applications. KHS worked with igus for a year to test the rollers with iglidur jacket on a customer's application, and so far, little wear has been detected. These rollers work so well that they are also used in a modified form in the mechanical capping technology of other KHS systems. "Before we used the igus rollers here, we had to perform a central lubrication every four hours. KHS has now entirely eliminated all that," Blömker describes the changed process.

igus has been developing materials of its own, called iglidur, since 1983. They are made of high-performance polymers with unique specifications: their composition makes them extremely wear-resistant, robust, and self-lubricating. Their service life can be determined precisely. Furthermore, each iglidur material has individual properties and strengths that make it suitable for specific applications. This is true of the materials that KHS uses in the InnoPET TriBlock. Its components are exposed to high loads and temperatures of around 50°C. The self-lubricating plain bearings, ball bearings and liners easily stand up to these operating conditions. "The demands on our systems and on the igus products will continue to increase. Our customers want even higher speeds, better performance and lower bottle weights. We will work with igus to fulfil these wishes," says Cornelius Adolf.

 

igus salesman Florian Blömker and Andreas Ullrich, Head of Mechanical Design in KHS's labelling technology product centre, next to the upper part of the labelling module in the InnoPET TriBlock (source: igus GmbH)

 

igus GmbH develops and produces motion plastics. These lubrication-free, high-performance polymers improve technology and reduce costs wherever things move. In energy supplies, highly flexible cables, plain and linear bearings as well as lead screw technology made of tribo-polymers, igus is the worldwide market leader. The family-run company based in Cologne, Germany, is represented in 31 countries and employs 4,900 people across the globe. In 2021, igus generated a turnover of €961 million. Research in the industry's largest test laboratories constantly yields innovations and more security for users. 234,000 articles are available from stock and the service life can be calculated online. In recent years, the company has expanded by creating internal startups, e.g. for ball bearings, robot drives, 3D printing, the RBTX platform for Lean Robotics and intelligent "smart plastics" for Industry 4.0. Among the most important environmental investments are the "chainge" programme – recycling of used e-chains - and the participation in an enterprise that produces oil from plastic waste.

 

www.igus.eu