In-mold labelling (IML) is ideally suited to meet today’s customer requirements in the plastics industry, especially in the packaging segment. Companies need high-quality, durable machines with maximum availability that can produce a wide range of packaging designs with great flexibility and minimal cycle times. To implement such systems efficiently, Swiss specialty machine manufacturer Beck Automation implements PC-based control and drive technology from Beckhoff as its standard automation technology.
“Family-run Beck Automation in Oberengstringen, Switzerland, founded in 1934, is a pioneer in the field of in-mold labelling systems with more than 30 years of experience,” says Nino Zehnder, head of sales and a member of the executive management team. To meet the needs of its customers all over the world, the company’s product portfolio ranges from cost-effective basic machines to custom-tailored systems. A current example of innovative solutions from Beck Automation is a six-way IML system for decorating plastic lids. Zehnder explains: “This machine is for plastic containers used in the food industry. The most common items being made with it are lids to cover 1-litre containers for products such as yogurt, but the same machine can also decorate the body of the container.”
IML as a particularly flexible process
With in-mold labelling, a previously printed label that has the same base colour as the final product (for example, the lid of a yogurt container) is placed in an injection mold. When the plastic is injected, cools down and hardens, it combines with the label to form the finished product. This process is more flexible than affixing printed labels, says Zehnder: “IML is especially suitable for packaging design in the age of Industry 4.0 and lot sizes of one because you don’t need to modify a printing machine for every change, which is expensive and time-consuming.”
The Beck Automation system can produce up to 5000 plastic lids per hour, each with its own design or even an individual QR-code if necessary. For precision and durability, the IML system is mounted on a solid welded steel frame. The system attaches laterally to an injection molding machine so that its servo-controlled shuttle arm can reach into the mold. When the shuttle arm moves into the open injection mold, it picks up six finished lids on one side while simultaneously inserting six new labels for the next injection molding process. During this process, the IML machine inspects the lids with a vision system for quality assurance before stacking them. During the stacking process, the machine also separates the next six labels in order to place them on the main shuttle arm for the next insertion pass into the injection mold.
Zehnder points out the performance capabilities of the IML machine: “The entire cycle with six plastic lids takes only about four seconds. The machine also features exceptional flexibility. It can be adjusted for other lid sizes, shapes or quantities very quickly and easily. Another advantage is the automatic magazine changeover, which makes it possible to refill the labels without interrupting the process.”
Advantages of PC-based control technology
As Christoph Jenni, head of software development, explains, Beck Automation first decided to use PC-based control technology in 2011: “Even back then, PC-based control technology impressed us with several basic advantages such as the ease with which you can implement remote access for effective customer support. Another outstanding feature of PC-based control from Beckhoff was the ability to make system changes online Compared to the previous PLC-based solution, we also benefited from the powerful axis control with extensive diagnostic capabilities as well as from the fast and easy-to-use EtherCAT communication standard, which replaced the traditional individual wiring.” Zehnder also points out the benefits of a Windows-based software system: “Its openness ensures maximum flexibility. For example, we can easily export data as an Excel file or use Windows’ many capabilities for a user-friendly operator interface.”
According to Zehnder, the worldwide availability of Beckhoff technology and support is also important for a globally active company like Beck Automation: “Since our systems are extremely durable, we must also make sure that the components are available for the long term. Even after 10 years or more, spare parts and newer, yet fully compatible products are still readily available.” Another factor is the exceptional modularity and scalability of PC-based control, adds Christoph Jenni: “Depending on the machine’s size and features, the control technology can be optimally adjusted without requiring much additional engineering. For example, we can easily adapt the number of servo axes to the respective requirements. And unlike other systems, PC-based control offers an unlimited number of I/O channels, which leaves all options open.”
Servo drive technology increases machine flexibility
Beck Automation also employs Beckhoff servo drive technology throughout its new six-way IML system. Its easy configuration results in significant benefits, particularly during setup changeovers. The machine features four AM8000 series servomotors, which are controlled by TwinCAT 3 NC PTP software via two single-channel AX5103 and AX5118 Servo Drives, or a two-channel AX5203. The AM8063 servomotor with 29 Nm of standstill torque makes for a highly dynamic main axis. There are also two AM8032 (2,37 Nm) and one AM8033 (3,22 Nm) equipped with holding brake, which are used to implement, among other things, the shuttle motion in order to guide the plastic lids along the inspection system with a sufficiently short cycle time.
In addition, the servo drive technology is much less jerky than pneumatics, which increases the machine’s durability due to the reduced inertia forces. The other servo axes are used to take the labels from the magazine and to stack the finished lids. “Another positive feature is the one cable technology (OCT) from Beckhoff,” explains Jenni. “OCT reduces the wiring and assembly effort significantly, and the electronic type plate makes it much easier to commission, troubleshoot and possibly replace devices.”
A Beckhoff CX5130 Embedded PC with an Intel Atom processor running at a clock speed of 1,75 GHz provides sufficient performance for all control and motion sequences. The broad spectrum of the Beckhoff Industrial PC portfolio is another critical advantage. Jenni elaborates: “Depending on the requirements or the size of the machine, you can easily deploy more powerful IPCs or multi-core processor technology without having to change the control software. This makes us highly flexibly as far as the system design is concerned.
“The same applies to the TwinCAT software. The existing motion control library has met all our requirements so far. We could even implement special features like data exchange via OPC UA very easily with the help of a corresponding TwinCAT function. Plus, the integrated TwinSAFE solution has delivered additional efficiencies, because the EL6900 TwinSAFE Logic terminal and the optional AX5801 TwinSAFE cards for the drives made it possible to significantly reduce the wiring and the space requirements for the safety doors and the emergency stop function.”
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