Simply delicious, simply good

Its products are enough to make connoisseurs of high-quality chocolates and pralines go weak - but the new decorating machine from Bühler GmbH is also impressive from a technical viewpoint. Thanks to an intuitive editor, intelligent automation and a versatile technology platform, even elaborate decorative finishes can be created with ease - even better than by hand.

For Bühler too, craftsmanship remains the order of the day. At the Application Center in Reichshof, Germany, technologists from Bühler GmbH test processes, raw materials, and parameters to ensure that the high-quality chocolates and pralines not only have the correct melt quality, but also a perfect appearance when they emerge from the company's machines and production lines. This requirement also presents some challenges for machine development, explains Daniel Wittmaack, Head of Product Management & Process Engineering at Bühler in Reichshof. "One of our latest machine solutions was about applying three-dimensional decorations to chocolate figures or individual chocolates. To do this, we move the product molds on a lifting table with a total of three axes beneath the dispensing units along defined paths so that we can apply the desired decoration with extreme precision." In order to automate this movement of the lifting table, Bühler tested widely differing approaches in advance, as Wittmaack explains: "There were two points that automation had to ensure: On the one hand, we need very precise motion control in spatial terms, so that we can apply the delicate decorative elements very accurately. On the other hand, the system must be so easy to use that any machine operator can intuitively position the decorative elements on the basis of a model and optimize the process without requiring any special knowledge."

Bühler GmbH

Bühler technologies are an integral part of the everyday lives of billions of people - even if most of them may be unaware of it. With its Advanced Materials, Grains & Food and Consumer Foods Business Units, the company plays a significant role in the production of food, but also of energy-efficient vehicles and buildings. The Reichshof facility belongs to the Consumer Foods Business Unit and is where Bühler develops and produces solutions for molding and decorating chocolate in any shape. To this end, experienced process engineers and technologists work alongside the user to develop tailor-made process solutions ranging from dispensing, weighing, mixing, cooking or aerating of masses, to extruding, forming, cutting, tempering, coating and cooling.

From idea to solution

One key component of the automation solution was soon determined: The SIMATIC S7-1500T enabled Bühler to rely on a correspondingly versatile platform, which in principle allows numerous technologies to be used for motion control, as Karl-Jürgen Kasemann, Lead Project Engineer Automation at Bühler, confirms: "This controller enables us to use different kinematics, but also cam plates - so at this level, we had all the options." However, finding the right solution for this process was not that easy at all: "One of the things we considered here was whether we could adapt an approach from 3D printing. At first glance, the process appears similar, but you work in layers rather than in a single pour. What's more, we are dealing with tiny, delicate decorative elements that many kinematic solutions simply cannot resolve finely enough. So we had to keep looking." In the end, another technology was used that had already been tried and tested at Bühler. The movements of the lifting table are stored as cam plates, which are transferred as polynomials from a special decorating editor to the SIMATIC controller. "The great advantage of this process for us was effectively that, starting with the control system, we were working with systems and technologies that we were already using in many other processes. This allowed us to focus entirely on the aspect of user-friendliness."

From model to decoration

The result of this development is now already in use in the first decorating machine: A specially developed decorating editor in which the system operator can set the appropriate points for the decorative elements on the basis of the 3D model of the product - for example, a chocolate praline. From these points, the editor calculates the corresponding paths for the machine control. What's special about it is that process adjustments are also possible during runtime and directly at the machine. The editor is embedded in the machine visualization on the SIMATIC Panel PC and is called up by the operator at the touch of a button - "system operators do not even notice that they are using an independent application. It feels the same to them as their familiar HMI." Behind this seamless user experience, however, lies a considerable amount of program development effort, in which Bühler worked closely with software development specialists and experts from the Siemens Application Center. "In particular, the data transfer to the controller was a point that worried me at the beginning. But with the integrated OPC UA communication of the SIMATIC S7-1500 this was really easy to integrate."

Our users can change the product or decoration at the machine at least 50 % faster using this machine. On top of that, they save another 30 % or so of time taken to run in the machine."
Karl-Jürgen Kasemann, Lead Project Engineer - Automation, Bühler GmbH

From development to application

Accordingly, the actual project implementation went very smoothly, recalls Kasemann: "At the outset, we invested a lot of time in selecting the right technology and the right software for the decorating editor, and we also benefited greatly from the collaboration with Siemens. The programming of the automation itself was then actually the easier part. On the one hand, we made use of the scalability and versatility of the SIMATIC controller, and on the other hand, the integrated project planning with one engineering system extending from the HMI, via the CPU, to the drives and servo motors helped us implement the right solution efficiently." The crucial point for Kasemann, however, is that the new machine offers precisely those advantages in production that the developers had set as their target: "Our users confirm to us that, with this machine, they can change the product or decoration on the machine at least 50 % faster. On top of that, they save another 30 % or so of time required to run in the machine because they can better adjust and optimize the decoration. Feedback like this is clear confirmation that we have followed the right direction with this process," he concludes.

Even more support for the user

But the experts at Bühler are already thinking ahead. In the next step, the decorating editor should be able to automatically recognize decorative elements based on the 3D data and suggest them to the machine operator. "This allows our users to produce even more customized products with even shorter changeover times," adds Wittmaack. Until that time, he remains very satisfied with what has already been achieved: "With the new decorating machine, we combine flexibility, user-friendliness and quality - and that makes it a really attractive package for our users."

The new decorating machine combines flexibility, user-friendliness and quality – making it a really attractive package for our users."
Daniel Wittmaack, Head of Product Management & Process Engineering, Bühler GmbH

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