When Wal-Mart asked 100 of its top suppliers to tag shipments with radio frequency identification (RFID) tags by January of this year, not everyone was optimistic that it could be done. But eight months into the program, Christi Gallagher, Wal-Mart's spokesperson for RFID technology, confirms that more than 100 suppliers currently are shipping tagged cases and pallets to Wal-Mart's Dallas/Fort Worth distribution centers.

Helping the adoption along are newly ratified standards that are making RFID more affordable and functional. The reliability of readers, antennae, and other RFID components has improved as technology providers learn more from their test facilities. It comes as no surprise, then, that other major retailers are now jumping on the RFID bandwagon. Warehouse managers must face the inevitable and ask themselves, how can I prepare my warehouse for RFID?

There are many ways to apply an RFID tag, but they all share a few common steps. Unique product information must first be translated into an Electronic Product Code (EPC). This EPC data must then be electronically written to an RFID tag. The tag is applied to the pallet or carton, then verified to ensure its readability.

The most popular tags in use today are the passive ultra-high frequency (UHF) tags that have no on-board power supply. UHF tags' antennae capture energy from RF signals to power the chips. These tags are available either as adhesive inlays that are separate from the bar code label, or as "smart labels." Smart labels have RFID adhesive inlays attached to thermal-transfer labels for use in printers, allowing bar-coded and human-readable information to be printed on one tag.

How you set up an RFID tagging operation depends in large part on the volume of cases and pallets requiring tags. At this early stage, the number can be surprisingly small. Conair, one of Wal-Mart's suppliers, has been tagging since January. "Currently we are working with only one Wal-Mart [distribution center], so we are looking at about 10 to 15 pallets per week," says Ben Albence, corporate director of warehousing and distribution.

Many shippers are in the same boat. With only a small volume requiring tagging, the so-called "slap and ship" approach is most commonly used. In this type of operation, pallets of picked orders headed for RFID-enabled facilities are transported by lift truck to a section of the warehouse where RFID tags are manually attached and their readability verified before shipping.

Shippers that have advance knowledge of orders may hire outside contractors to generate encoded RFID tags, or they may create tags themselves. The tags are brought to the slap-and-ship area, where workers match them to the proper pallets or cartons.

When cartons carry RFID tags, the tasks of de-palletizing, labeling, verifying, and re-palletizing become more labor-intensive. Ergonomic workstations can help to improve throughput. For example, pallets can be accumulated onto gravity-flow tracks that index each pallet to a lift table. The lift table adjusts to the elevation desired by the worker. He or she slides (rather than lifts) the carton from the pallet, scans it for identification, and prints a smart label on a tabletop printer/encoder. The worker applies the label, then slides the carton to a second worker, who uses a handheld device to verify the tag's readability and then re-palletizes the carton.

Workers at a slap-and-ship operation need to be trained in basic RFID principles, as well as the following:

• Proper tag placement for maximum readability. The tag position for one type of item may not work for another. For example, metals tend to reflect and liquids tend to absorb radio signals;
• Proper method for removing the adhesive layer to reduce damage to the RFID inlay;
• Tracking the quality and quantity of tags on hand to ensure sufficient quantities are available when needed;
• Proper arrangement of cartons on a pallet so that RFID tags are not buried or near RF-interfering material;
• Correct use of the printer/encoder;
• Keeping cell phones, cordless phones, and wireless LANs away from workstations, as they interfere with radio frequency signals.

Scanning equipment for RFID is similar to what's already in use. Instead of pointing a scanning gun at a bar code, workers must be taught to wave handheld readers in a specific area.

As with any new technology, errors, problems, and lessons learned must continually be shared between suppliers and customers, as well as with warehouse workers. But all in all, minimal training is required, and RFID application remains a simple pick-and-label process, says Conair's Albence.  Continued...

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