Radio frequency identification (RFID) technology is being used to manage the flow of 12,400 pallets within a fast moving high-bay warehouse for fresh fruit.
The Netherlands is known worldwide as an exporter of fresh fruit. The country producers a wealth of different varieties. These are planted, irrigated, fertilised, harvested, and then there is the challenge of storage and distribution. Key to success is the ability to deliver large quantities of the various fruits to supermarkets as quickly as possible requiring fast accurate processing within the order-picking warehouse.
H M de Jong, based near Rotterdam, has set up a new, innovative and low energy consumption high-bay warehouse for fresh fruit, holding up to 12 400 pallets. Because the Ridderkerk facility is handling fresh fruit it has a very rapid turnover of storage locations, where the speed of handling ensures the consumer can be supplied quickly with fresh products.
For this new distribution centre, numerous roller and belt conveyors for transporting and sorting the harvested fresh fruit, plus workplaces for fruit care needed to be intregrated with the right identification technology to ensure the efficient flow of goods. To achieve error-free data and thus ensure the efficient flow of goods, the warehouse management system needed to reliably identify the pallet of fruit and so H M de Jong selected proven and reliable partners in Egemin for the conveyor and storage technology, and Leuze electronic as specialists for identification technology.
Leuze electronic, experts in both optical and RFID identification, was able to offer a range of solutions and present the best solution for the application. In summary the technical possibilities and considerations were:
- Barcode technology which functions quickly, is economical and well proven, was not ideal because of the risk of the fresh fruit or moisture soiling damaging the barcode labels, and making error-free identification uncertain.
- Compared with optical methods, RFID is a more robust technology in terms of its ability to withstand extremely adverse environmental conditions and negates the risk of soiling and other damage to code labels. Because data transmission occurs via a magnetic field, RFID systems are capable of identifying items through materials and so the code or data-carrier can be covered or indeed fitted inside a tray, without impacting on the reliability of the identification tasks.
Thus the Dutch company opted for an RFID system, which was ideally suited for this application, because of its robustness.
RFID is the only IDENT technology capable of updating data during processing (ie writing), and one or more targets can be transmitted to the transponder. As a result, it is possible to implement multiple control options for the pallets or containers. In the system used at de Jong, fruit is transported, picked and stored in plastic containers and cartons on pallets and for a smooth process, each step must be tracked and the status of each pallet should ideally be available at all times.
The pallets arrive from the fruit farms in widely varying conditions and therefore, the pallets are placed on system pallets referred to as 'slave boards'. An RFID transponder is mounted in the geometric centre of the slave board, to ensure reliable detection regardless of the direction of travel, whether lengthways, sideways or diagonally. When the merchandise is placed onto the 'slave pallet' an assignment is made which is unique and traceable.
The readers fit perfectly between the rollers of the material handling systems and read the desired transponder data (eg, the pallet number) from below as the pallets pass by. The protected mounting location of transponders and readers, together with the short distance, guarantees very high functional reliability. The configurable function of the read/write device and the block structure of the transponder memory allow information to be read from the transponder or written to it. The path of the pallet can be reliably detected and controlled, independent of whether the pallet is being stored with a new load or if the fruit is being transported for order picking. In addition to the traceability, a very high level of system availability is attained, thereby making it possible to flexibly react to various influences. The locations of the individual pallets can be called up and traced at any time. Thus, fast and smooth order processing is ensured, even with varying stock levels or in the event of system malfunctions. The merchandise can be transported to the customer even fresher.
In the future, the use of RFID technology will not only ensure stability with respect to environmental influences, but it will also be able to satisfy new requirements currently being developed for the area of food production (eg, detailed documentation of process steps above and beyond EU-VO 178/2002 or the traceability of individual products).
Leuze electronic Ltd is based in St Neots, Cambridgeshire, UK. www.leuze.co.uk
