Global dairy products company Tnuva produces cheese and other food products sold to consumers throughout Israel, the Middle East, Europe and the United States. The manufacture of high-quality cheese is a sensitive process that requires heating, cooling and soaking at very specific lengths of time. If any mistakes are made, an entire lot must be discarded.
Five years ago, the company began using LogiTag Systems‘ RFID technology at one plant, to track the process of manufacturing cheese on conveyor belts. A few years later, it expanded the deployment to a second factory, to monitor a more complex process in which batches of cheese pass through a series of stations before being loaded onto pallets and then being shipped. For the second installation, completed in 2011, LogiTag active RFID tags are used to track carts filled with product that move through coolers, heaters and pools of saline water, while passive ultrahigh-frequency (UHF) tags help the company to manage the movements of loaded pallets after production and until the goods are loaded onto trucks.
Next year, Tnuva intends to install an RFID system to track cheese production at a third Israeli facility, though details regarding that deployment cannot yet be released, according to LogiTag.
Tnuva has reported to LogiTag that the technology has led to fewer errors and increased efficiency at both plants. Thanks to the RFID technology, plant managers can now identify when any given product could be at risk of an error (such as cheese production failing to complete the necessary processes within the expected amount of time). The managers have also been able to increase plant efficiency, by reviewing the RFID data to identify bottlenecks and adjust product flow accordingly.
Initially, says Shlomo Matityaho, LogiTag’s CEO, introducing radio frequency identification to the production plants proved challenging, since the manufacturing of cheese poses a harsh environment for RFID technology. At the processing plants, there is not only a great deal of metal, but also liquid—both of which can compromise UHF RF transmissions. Therefore, the company recommended passive low-frequency (LF) technology for the first site, and active RFID tags for the second.
The first facility, located in Afula, Israel’s North District, produces hard cheeses, employing a process that involves preparing a cheese mix within a large silo, after which 4-by-10-inch molds of cheese are created that fit into a reusable plastic box measuring 14 by 30 by 6 inches in size. Boxes filled with molds pass down a conveyor belt and undergo processes whereby they are heated to temperatures as high as 120 degrees Celsius (248 degrees Fahrenheit) or cooled to about 0 degrees Celsius (32 degrees Fahrenheit).
Tnuva’s staff apply an HID Global LF 125 kHz tag to each box. The tag is encoded with a unique ID number that is linked, in LogiTag’s software on Tnuva’s database, to data about the specific cheese inside the tagged box, including the date and time that it was mixed, as well as its batch number. The tags are read at five key points along the conveyor line, indicating each process has been completed, and a date and time stamp are assigned in order to ensure that nothing fell outside the acceptable parameters. The LogiTag software then provides the company not only with alerts if time requirements are not met, but also historical data to help managers track product flow for each batch of cheese.
That system, installed in 2008, has since saved the company money, Matityaho reports, by reducing the number of batches that would otherwise have been discarded had it not been able to ensure the correct procedures were completed. Tnuva was also able to institute ways to make its operations more efficient, by adjusting production processes based on RFID-derived information regarding the movements of products.
Three years ago, the company decided to expand the RFID solution to its facility in Kiryat Malachi, south of Tel Aviv, where it produces Bulgarian cheese. In this case, the production process is more complex. Each batch of cheese mix is poured into molds, which must then undergo a process of heating, cooling and immersion in pools of salted water. Because the product moves from one station to the next, rather than down a conveyor, LogiTag implemented a system whereby RFID readers were installed at key locations, in order to track LogiTag proprietary 433 MHz active tags mounted on the carts that plant personnel use to transport the cheese mix through the production stations.
First, when a cart is loaded with a stack of cheese molds, workers update the LogiTag software to indicate which batch is associated with the unique ID number on that cart’s 433 MHz active tag. The cart is then wheeled to a station where each mold is shaken and turned. At this location, it is important that each mold be shaken and turned only a specific number of times, and the LogiTag readers installed there interrogate the tags via LogiTag’s proprietary air-interface protocol. Based on the collected RFID data, Tnuva’s management software tracks the number of shakes the cheese has undergone, and updates that information for the specific mold, based on the cart’s unique ID.
The cart then proceeds to one of 64 pools of salted water, each designated for a specific type of cheese. Prior to the RFID solution’s implementation, staff members used a board posted on the wall to hand-write updates indicated which products were immersed in which pools, when this occurred and when the process was completed. Now, the collection of data about this procedure is automated. Each pool has its own LogiTag RFID reader to capture the ID number of a tag attached to a crane that lifts the cheese cart and places it into the pool. The interrogator also reads the cart’s RFID tag ID and, based on the order in which it reads the crane and cart tags, the software can determine whether the cheese is being placed into the pool, or being removed.
Another LogiTag reader, installed at a cooling unit, reads the ID of each cart as it arrives and then leaves. In this way, the system can determine how long the cheese was cooled at a specific temperature.
If something goes wrong, such as a cart being left between processing steps for too long, the software issues an alert to management. This enables the managers to quickly dispatch personnel to locate the cart and prevent the batch in question from spoiling.
Once the cheese has completed its processing steps, it is removed from the cart, packaged and loaded into cartons stacked on a pallet for shipping. Here, the pallets have a Smartrac (UPM) or Alien Technology UHF passive tag attached to them. The tags are read using Feig Electronics UHF readers at the time that the products are placed in the warehouse, and again as they are shipped. This data provides Tnuva with information indicating how quickly finished product is being shipped, and when it is sent out to specific customers. Meanwhile, the now-empty empty cart is cleaned, and its LogiTag active tag ID is cleared from the software for use with a new batch of cheese.