Sweet trace of chocolate

28 July 2008

In a factory near Neuwied, in Germany’s Rhineland-Palatinate, production systems are developed and manufactured to bring us high-quality confectionery.

Now, Turck has supplied RFID systems to boost efficiency, safety and control by ensuring transparency in mould logistics.

An RFID BL ident system has been applied to confectionery production systems manufactured by mechanical engineering specialist, Winkler und Dünnebier (WDS) at its Rengsdorf plant.

The company manufactures production lines for a wide range of products. Moulding lines for hard sweets and toffee products, shelling moulding systems for filled and solid chocolate products, mogul plants for all starch-moulded products, machines for flat chocolate products and universal piston extruders for plastically formable masses.

In addition, Rengsdorf also supplies laboratory depositors for product development catering for a range of applications.

Producing a filled chocolate article such as chocolate candy, involves many different processes. The first of these is the so-called mould insert station. It is here that the moulds, loosely lying on feed chains, set off on their journey round the production plant. The moulds are moved intermittently or continuously by means of aligner chains.

Once the moulds have been heated the first moulding machine deposits chocolate into the mould to produce the shell. The moulds are then shaken, turned upside down and spun carefully while being cooled. The chocolate shells are left in the cooling cabinet to harden.

With Turck RFID support the user keeps an overview of the range of moulds
With Turck RFID support the user keeps an overview of the range of moulds

The second moulding line supplies fillings such as nougat or fondant. The principle is the same: heating before filling and cooling down afterwards. The smooth underside of the chocolate candy is then produced by melting a second application of chocolate, removal of the superfluous mass and final cooling. At the end of the line, the product is dislodged from its envelope by light blows to the back of the mould with pneumatic hammers. While a conveyor belt takes the finished item to the packaging line, the moulds initially remain in the production cycle. They are transported to a changing station, where they are checked for product residues and replaced by new empty moulds if required. The entire installation is managed by a PLC, as well as motion controllers for the servo section. Operator PCs or CE Clients, which are linked to a central server, can be found at every moulding machine.

All plastic moulds are equipped with RFID data carriers. Permanently installed read/write heads in the production lines and mobile acquisition systems at warehouses and production areas allow the progress of each mould to be traced from a central station.

The database-oriented RFID system helps to ensure optimum mould and product tracking. But how does this help the production processes? The answer is in many ways.

The systems ensure that the central server database of every WDS machine contains valuable information that can be used to optimise both plant productivity and production quality. There is a range of possible applications for the data pool, including optimising logistics. The system will show the location of every mould or trace the route it has taken within the production plant. This allows potential error sources to be easily located.

Production-specific data can also be determined. For example, it is possible to easily identify moulds or even complete mould sets that produce above-average levels of scrap, and sort them out automatically. Another application could be comparing mould sets and production characteristics of a specific batch.

The data pool provides a wide range of applications for in-plant monitoring of quality or hygiene guidelines, not least in terms of quality management. The system can easily identify whether a cleaning cycle has been correctly followed. Today, it is possible to closely track production sequences, such as pushing together moulds in the cooling cabinet or exchanging them for special test-samples – during operation, thanks to RFID. This technology also instantly emits an alarm if inserted moulds are not suitable for the production process currently underway. Even a ‘flying’ product change is possible. Here, new moulds are introduced to the system while the old ones are ejected. Production scenarios with mould sets mixed at random are possible to increase flexibility.

WDS is now equipping all plastic moulds with RFID data carriers
WDS is now equipping all plastic moulds with RFID data carriers

Bernd Plies, head of electrical engineering and automation technology at WDS, said: ‘The BL ident system offers hardware with standardised interfaces that are suitable for industrial applications.’

He continued: ‘We were won over by the option of combining Turck’s RFID system with the bus systems, such as Profibus, Device-Net and Modbus IP, in use at our plant, as well as the scope offered by future bus systems’.

Implementation went smoothly, according to Plies.

‘All components supplied were swiftly incorporated in the first WDS application, which was realised with Step7. And when one or two queries did crop up, they were quickly sorted out on the telephone.’

The two companies worked closely together and Plies said this was an advantage.

‘Co-operation with Turck has been constructive at all times,’ he said. ‘The close contact with Turck’s developers was of great benefit to us’.

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