DaimlerChrysler Putting RFID Tags in Kanban Cards

The advantage of this real-time transparency of supermarket stock reportedly eliminates the need for manually intensive and time-consuming stock counts. In addition, with an accurate and automated inventory in the supermarket, the automaker could automate part orders, requests and inquiries from the supermarket to suppliers.

During the proof-of-concept test, passive EPC Gen 2 UHF RFID inlays were added to the kanban cards, and a reader with an RFID interrogator antenna was deployed on each side of the gateway between the parts supermarket and the factory shop floor.

Reusable containers in the form of trolleys and trailers are used to bring parts from the supermarket onto the production floor. The exterior of these containers were fitted with slots to hold the kanban cards. While the existing text-only cards could be placed in a parts trailer, DaimlerChrysler found that the RFID-enabled cards had to be placed on the outside of the container to ensure they could be read. Containers could be manually pushed, driven by forklift or pulled by an electric train. Operators would check a screen display of the interrogator reads to ensure every card had been read as the containers passed through the RFID-enabled gateway. The parts staff also had to ensure that only a single load of containers was permitted to go through the gateway in a single direction at a time. In addition, the RFID-enabled cards had to be more than 50 centimeters from the antennas as containers passed through the gateway's 4-meter-wide opening.

Once these criteria were met, DaimlerChrysler says, the company achieved 100 percent read rates with its RFID-enabled kanban cards. During initial tests, which involved EPC Gen 1 tags, only 70 percent to 80 percent of the kanban cards' tags were read—a level so unacceptably low that DaimlerChrysler considered a move to active tags.

DaimlerChrysler turned to Intel to provide the hardware for the RFID proof of concept, and SAP to develop software to manage the readers and the data collected. The next step, according to the automaker, is to run a pilot at two of its Unterturkheim plants, involving a total of five gateways at four supermarkets.