Beck Automation in Oberengstringen was founded in 1934 and, with over 30 years of experience, is a pioneer in the field of in-mold labeling systems. The spectrum of machines ranges from cost-effective basic systems to customer-specific special machines. A current example of the innovative solutions from the family-run company from Switzerland is a 6-cavity IML system for decorating plastic lids, the use of which is explained by Nino Zehnder, Sales Manager and Member of the Management Board at Beck Automation: "This system is used for plastic packaging in the food sector. The most common product manufactured with it are lids for 1-liter cans for yoghurt, for example. However, the same machine can also decorate the can itself."

In each process step, the IML system removes six labels from a magazine and inserts them into the open mold of the injection moulding machine.

© Beckhoff Automation

With in-mold labeling, an already printed label is placed in an injection mold that has the shape of the desired end product - for example, the lid of a yogurt can. Plastic is then pressed into the mold. The plastic cools down in the mold, hardens, bonds with the label and ultimately forms the finished end product. According to Nino Zehnder, this process is characterized by its very high flexibility compared to film printing: "From the perspective of batch size 1 production and Industry 4.0, IML is particularly suitable for packaging design. This is because no expensive and time-consuming printing machine process has to be converted in the event of changes. This means that up to 5,000 plastic lids can be produced per hour and, in extreme cases, each of them can be produced with a new design or an individual QR code."

For precision and a long service life, the IML system is based on a solid steel frame. It is positioned at the side of an injection molding machine. The actual core of the system is its servo-controlled main arm. This arm moves into the open injection mold, removes six finished lids on one side and simultaneously inserts six new labels for the next injection molding process on the other side of the mold. During this process, the IML system processes the removed lids, i.e. they are checked for quality using a vision system and then stacked. At the same time, the next six labels are separated in order to load the main arm for the subsequent insertion into the open injection mold.

"The entire cycle with six plastic lids at a time only takes around four seconds," says Nino Zehnder, illustrating the efficiency of the IML system, adding: "It can also be quickly and easily changed to a different size, shape or number of lids. Another advantage is the automatic magazine change, which allows the labels to be refilled without interrupting the process."

The advantages of PC-based control technology

Beck Automation decided to use PC-based control back in 2011, as Christoph Jenni, head of the software department, explains: "PC-based control technology already had a number of fundamental advantages back then - for example, easy remote access for supporting our systems directly at the customer's premises. With the Beckhoff solution, the online change option was another useful feature. Compared to the previous PLC-based solution, we benefited not least from the powerful axis control with comprehensive diagnostic options and the use of the fast Ethercat communication standard as a replacement for the previous individual wiring." Nino Zehnder adds the specific advantages of a Windows-based system: "The corresponding openness ensures maximum flexibility. For example, data evaluations can be saved directly as an Excel spreadsheet without much effort or a wide range of options for a user-friendly HMI can be used."

The focus remains on the modularity and good scalability of PC-based control, as Christoph Jenni confirms: "Depending on the machine size and equipment, the control technology can be optimally adapted without requiring a great deal of engineering effort. For example, the number of servo axes can be easily adapted to the respective requirements. In addition, PC-based control does not limit the number of I/O channels, leaving all options open."