Automated format adjustment
September 14, 2022
Flexible filling technology
The Krones AG, headquartered in Neutraubling near Regensburg, is characterised as „Synonymous of systems engineering“, and this is no coincidence. Complete filling machines and plants are developed and manufactured by the company, and shipped to renowned customers in the process, filling and packaging technology sectors around the world.
Since its foundation in 1951, the company has developed into a „full service partner“ for its customers: Krones combines machine construction, know-how in plants, process engineering, microbiology and information technology.
One example of this is shown in the filling technology. In this area, Daniel Ludwig, design engineer, is working on making filling technology and capping machines more flexible with the UnitXpress system.
The rotary machines typically fill water and carbonated beverages into classic PET bottles of various sizes. After the filling, the bottles are capped, labelled and then packed into bundles with, for example, four or six bottles. In some cases the labelling takes place before filling the bottles. On their way through the filling line, the bottles move on
socalled pitch circles that merge into one another. This requires the containers to be guided. On the one hand, it must be ensured that the bottles are held on the pitch circle and not deflected outward, for example due to centrifugal forces.
In addition, stabilization in the direction of travel is necessary. In filling technology, these stabilizing guides are called handling parts.
If a filling company processes several containers, several sets of handling parts are often necessary due to the different geometries.
Each set of handling parts is then individually adapted to each bottle.
„That quickly adds up to 30 minutes until the entire machine is changed over“, describes Daniel Ludwig, who implemented the automation of this plant. For comparison: in Krones‘ rotary machines, up to 45,000 bottles are filled and packaged in 30 minutes while the line is running.
In the classic format changeover, these guides are adapted with the handling parts in a time-consuming process. If the format of the bottle changes, for example, from 1.5 l to 0.5 l, the plastic parts have to be replaced mechanically in many places and by the machine operator on site – even in the filling area. „That quickly adds up to 30 minutes until the entire machine is changed over“, describes Daniel Ludwig, who implemented the automation of this plant. For comparison: in Krones‘ rotary machines, up to 45,000 bottles are filled and packaged in 30 minutes while the line is running.
In addition to the time required for the changeover, there is also additional cleaning work. Every time employees enter the sensitive filling area, hygienic conditions have to be created again and possible contamination and germs removed. Furthermore, on-site storage capacity is needed for the sets.
Depending on how much and which bottle formats will be used, the filler has to store corresponding quantity of sets. If a machine is able to handle six different bottle formats, six sets of handling parts are also necessary (for example with various filled quantities 0.33; 0.5; 0.7; 1; 1.5 and 2 liters).
Automated format adjustment without sets
In the automated UnitXpress system there are no more sets, and the sophisticated design of the guides allows for different bottles shapes, for example different bottle bases. Thanks to fast and automatic changeover, format adjustments are also worthwhile more often during machine operation. The bottler can then adjust batches in line with demand and save storage capacity. For customers who fill various bottle formats on one machine and change over more often, a fully automated machine is the ideal solution.
Normally, several sets will be specifically designed for each bottle shape. With the UnitXpress system, one handling unit automatically adapts to each bottle. Its design also makes it easy to clean.
„If you compare the automation costs with the costs for the required sets, the automated machine can already be profitable with five different bottle formats. On some machine types with less, on others with more formats. Of course, it always depends on which machines are used by the customer“, says Daniel Ludwig about the cost-effectiveness of the automation.
Flexible systems are delivered completely pre-installed
As a supplier of system technology, it goes without saying that Krones provides the finished program for the changeover process in the machine control system. The group is already gearing its disclosures towards the appropriate setting options for the planned bottle formats. All holding and guiding devices are preset during planning and pre-assembly and saved in the machine control system.
During operation, the bottler only has to remember to actually change over the type and select the appropriate format at the push of a button.
For years, Krones has been registering both an increasing demand for flexible machines and customer inquiries for modernization of plants. Particularly when new bottle formats arise during the machine‘s runtime that were not envisaged when it was delivered, the fully automated line is more flexible, and all that needs to be done is to teach the new program. The procurement and storage process for new sets is eliminated.
The automated machine can thus be used for future bottle formats.
Flexible format adjustment with positioning systems from halstrup-walcher
For the automated adaptation of the sets of the filler outlet, the com-pany relies on positioning systems 3-series from halstrup-walcher GmbH. Due to the modular product concept, it can be decided depending on the installation space, if a PSE with IP54 or a PSW with IP68 made of stainless steel is used. The PSW are robust, tight and can also withstand the pressures and cleaning agents of the automatic Krones foam cleaning without corrosion. When changing positioning systems within the 3 family, no relevant mounting dimensions change and the software also remains the same.
„By using the PSW, we were able to dispense with complicated enclosures in the design and save space as well as material. Where enclosure is possible without further complications, we still use PSE“, says Daniel Ludwig about the installation of the devices in the plant. „Changing drives has been made easy due to the product family concept. As there is already a longstanding cooperation with halstrup-walcher, the software components of the drives are already known by our colleagues in programming".
Simple customer-specific adaptations of the positioning systems
Ludwig was supported by Michael Rossa, sales engineer at halstrup-walcher, in selecting the right equipment for his application. A direct, personal interface between Krones and halstrup-walcher is important to both sides. The medium-sized family business from Kirchzarten, with its approximately 180 employees, is a reliable partner for many well-known machine manufacturers, and supplies numerous customer-specific variants worldwide.
Also the PSW used by Krones, with the required torque of 18 Nm, was not yet listed in the catalog of halstrup-walcher, but the adaptation of a PSE to a PSW was successfully implemented in a short time, amongst others thanks to the high vertical integration of manufacture of the drive specialist. Not only in the design, but also in the provision of materials, the modification went smoothly: „We had expected more problems here due to the special material stainless steel - especially in terms of delivery times. But the adaptation was simple and straightforward, and the units were delivered quickly and reliably“, Ludwig describes the cooperation.
During commissioning of the systems, Rossa assisted in optimizing the factory preset parameters of the positioning systems. Direct communication was used to adapt the travel behavior of the drives to the application. A simple parameter change eliminated a mechanically induced error message, and the systems now run smoothly. With the bus interface of the positioning systems, such messages can be used in the future to draw conclusions about the design and to better monitor wear parts.