The company Ferag from Hinwil in the Zurich Oberland, which specializes in the development and manufacture of conveyor and processing systems, uses an RFID solution from Balluff for a special version of its 'Skyfall' conveyor system for filling, sorting and packaging silicone cartridges. This conveyor system overcomes longer distances and height differences in intralogistics, connects or decouples workstations and integrates filling, picking and packaging functions simultaneously in the smallest of spaces. It makes intelligent use of gravity and moves along free-fall routes without its own drive. This saves energy and reduces the number of drives required. Thanks to a permissible line layout with track radii of 500 mm and inclination angles of up to 6°, the system requires comparatively little space. This leaves plenty of space on the floor for open areas as well as the filling and packaging system.

Doubling output with Skyfall

The system also fulfills a special requirement of the user - namely to eliminate the existing operational bottleneck between the filling station and the case packers. This is achieved by Skyfall not only transporting the cartridges, but also acting as their intermediate storage. "In this way, the differing speeds of the filling and packaging process can be balanced out and a continuously high output of the system can be guaranteed. Compared to a previous solution, this has enabled production capacity to be doubled," explains Roberto Fenile, Development Manager at Ferag.

Cylindrical read/write heads, which are located at all relevant points along the transport route, read the UID code.

© Balluff

The conveyor system operates at a capacity of 12,000 cartridges per hour. The core of the overhead system is a rail system with three-dimensional kinetics and rolling elements, the shuttles. They are loaded with the building silicone cartridges, which differ not only in appearance but also in volume. The empty cartridges are fed from a storage bunker and then filled with specific quantities of building silicone at the end of the conveying and sorting process and fed to a case packer. Reliable identification of each individual shuttle is an absolute must for the process sequence. To this end, Ferag opted for an RFID-based identification process: "It works reliably even if the data carriers are contaminated with silicone residue," emphasizes Rolf Werner, Sales Engineer at Balluff.

With Skyfall, the type of transported goods is not limited to the cartridges, as the adapters of the shuttles can be individually configured and flexibly adapted to the respective application. In addition, the modular system can be expanded as required with specified standard elements such as circulating, ascending and descending conveyors, loading and unloading stations as well as infeed and outfeed diverters and thus adapted to new conditions.

Reliable even in metallic environments

Self-adhesive OnMetal RFID tags enable very flat identification of the shuttles.

© Balluff

The industrial RFID solution 'BIS M' from Balluff operates at a frequency of 13.56 MHz. It meets the high requirements in terms of clock rate and robustness and fulfills its task even in difficult metallic environments. In combination with passive data carriers, the high-frequency solution offers medium ranges of 20 mm and is therefore particularly suitable for close-range parts tracking or applications in production control or for traceability in quality management. At Ferag, the system documents the processes seamlessly and also provides real-time data for controlling and automating the entire material flow, including the filling and packaging process. The type and current location of each individual cartridge is known throughout the entire process. The data is managed in the system's central computer. Self-adhesive OnMetal RFID tags with dimensions of 36 mm × 8 mm × 5 mm - similar to a type plate - enable flat marking of the shuttles. As the data carriers carry a serial number permanently anchored in the memory (the so-called UID code or Unique Identification), the shuttles can be clearly identified at all times. The data carriers comply with ISO standard 15693 and offer a read range of 10 mm, even on metallic surfaces - which was one of Ferag's key requirements. This ensures seamless detection of the rolling elements throughout the entire material flow.

The UID is read by cylindrical M16 read/write heads from the 'BIS0140' industrial RFID system, which are located at all relevant points along the transport route, such as at switches. The data carriers do not require their own power supply as they draw their energy from the read/write units. Batteries are unnecessary, electronics and antenna are integrated in the tag.

Finding the right solution

An RFID solution stands and falls with the selection of the system and the optimum combination of tag, read head and controller. "The size of the tag and the geometry of the read/write head play an important role," explains Willi Brändli from Balluff TecSupport in Switzerland. "The RF field generated in the application must be large enough for the tag to remain in the field long enough to read the identity even at high speed. At the same time, however, it should be small enough that it does not overlap with the following tag during the detection process."

With an output of 12,000 cartridges per hour, the conveyor system works extremely quickly.

© Balluff

The RFID controller 'BIS V' is an 'all-in-one' unit that can be connected to up to four read/write heads. In combination with the read heads, it offers the required high reading speed. Thanks to the four ports, the number of controllers required is reduced, which lowers the overall costs for Ferag. An additional highlight: read heads of different technologies (LF, HF and UHF) can be connected - although this does not currently play a role in the Skyfall system.

Commissioning of the RFID system and handling of the controller are plug & play. The read/write heads only need to be connected to the front of the controller with plug connectors in order to be automatically recognized immediately. Two LEDs on each port signal the status and operating status to the user. As the controller supports the use of standardized frequencies, there is nothing to prevent the Ferag system from being used globally. In addition, the combination controller in a metal housing is available for the globally common Profibus, Ethercat, CC-Link, Ethernet/IP and Profinet bus systems. Ferag relies on Ethercat in the system presented.

A USB port on the controller serves as a service interface, for example for software updates and for commissioning without a PLC or controller. Additional sensors or actuators can also be connected to the RFID evaluation unit. The latter is realized via an integrated IO-Link master functionality. This makes it possible to determine further process information via the controller in addition to the identification of objects, such as the signals from trigger light barriers, inductive or capacitive proximity switches and distance or vision sensors with an IO-Link interface.

Author: Dr. Detlef Zienert is Press Relations Manager at Balluff in Neuhausen auf den Fildern.