Tagging Partial or Mixed-Case Pallets

By D'Anne Hotchkiss, Editor -- RFID News & Solutions, 8/30/2005

The problem of tagging partial or mixed-case pallets with RFID is being successfully solved through minor adjustments to business processes and RFID systems. Reading tags is the challenge. Tags on inside cases are not always read, and readers can pick up cases that are nearby, but not on the pallet.

Full pallets can be checked against the advanced shipment notice (ASN) to determine which case tags are not read. But once the pallet is broken down, the ASN information is no longer valid. Cases must be counted individually. Advises Ali Ebrahimi, product strategist for Menlo DirectTech, “The only way to do it is to move the pallet on a stretch wrapper to pick up all the signals and then assign a new ASN with the pallet number and all the cases on that pallet.” The customer can then use the new ASN for receiving.

The biggest challenge is reading tags attached to cases with high concentrations of metal or liquid, such as soup. Ebrahimi says, “the need to create a tiny amount of space (between cases) for the reader to pick up the signals is essential.” Because mixed pallets are frequently also only partially full, it’s easier to create that space.

On the outbound side, dealing with RFID tagging requires, “a sophisticated WMS (warehouse management system) because you’re telling it you expect to see 34 RFID tags, regardless of case size or case content. The WMS checks based on whether all the cases are captured or not.”

There are two easy ways to capture the information. One is to read each case as the pallet is built. The other is to read the tags by rotating the pallet on the stretch wrapper, without wrapping. Ebrahimi reports that with proper positioning of readers, it’s possible to recombine the reading and wrapping steps.

As with bar coding, when mixed cases are sent on a pallet, that pallet is assigned a Serialized Shipping Container Code rather than a Global Trade Identification Number Information, as dictated by business rules for the customer.