RFID Requirements

RFID IS IN-ADDITION-TO BARCODING

If you dissect an RFID tag you will find an inlay on the adhesive side of the label. The inlay contains an RFID chip that is integrated with a thin-film squiggly antenna. The antenna is fairly large while the RFID chip in the center checks-in at about 1 mm by 1 mm square. Any printer can apply print to a label surface, but to print the label surface AND encode the data to the chip requires a specialized printer which incorporates a wireless RFID encoder. The benefits of RFID are many but the primary benefit is that the data on the chip can be scanned wirelessly from as much as 100 feet away. Although that is very impressive, there are limits to the volume of data that can be carried on the chip. Which is why RFID doesn’t replace the other barcode labels that we are so used to seeing in logistics.

RFID

The DoD adopted RFID early on in the evolution of international standards for Auto ID technologies. One key concept for the evolution of Auto ID is that for something to be globally traceable it is going to need a globally unique serial number. The DoD already maintains a globally unique way of tracking defense contractors through CAGE CODES. So naturally combining Cage Codes and RFID Tag numbers is a perfect way to ensure that no two RFID serial numbers would be in conflict with one another.

There is no mil-standard for RFID, but there is a definitive Passive RFID Guide that defines how the DoD’s implementation of RFID fits in the international AIM standards. Mil-Std-129 also provides guidance for applying RFID tags to packaging.

RFID BASICS

When discussing RFID it is easy to think of it as one single technology. In truth Radio Frequency Identification encompasses several technology standards across several different Frequency Ranges. There is Passive Low Frequency (LF RFID @ 135 kHz); Passive High Frequency (HF @ 13.56 MHz); Passive Ultra High Frequency (UHF @ 868-915 MHz) and Active Ultra High Frequency (Active UHF 433 – 5.8 GHz). Passive RFID is a chip that derives its power from the Radio Frequency waves emanating from the Antennas – think of wireless Highway Toll systems. Active RFID tags carry their own power-source and which affords them more power to broadcast their signal. For DoD contractors, the primary technology is Passive UHF RFID. In fact equipment and labels are often designated as being for or compatible with EPC Class 1 Gen 2 RFID (where EPC stands for Electronic Product Code).

RFID tags are tracked via their serial number. The serial number is a 24 character hexadecimal number that is generated from three pieces of information: the contractor cage code; the tag sequence number; and the level of packaging. The three levels of packaging are the PALLET, the EXTERIOR CASE, and the ITEM-level. For shipping, the defense contractor is primarily concerned with PALLET RFIDs and CASE RFIDs.

RFID USAGE IN PRACTICE

RFID tags must be applied to all shipment handling units in a shipment. So if you are shipping 6 boxes via UPS you will need 6 Case RFID tags. If you are shipping a pallet with 10 cases on it, you will need 1 PALLET RFID and 10 CASE RFIDs. That means the shipper will need both PALLET designated and tags that are CASE designated.

All RFID technologies have distinctive performance characteristics. While Passive UHF tags have many desireable characteristics contractors need to avoid the most compromising scenarios which are spelled out in the official compliance guide and mil-std-129. UHF RFID tags do not work well when they are in contact or near contact with metal surfaces. Pallet RFID tags should be affixed to pallet placards – not directly to CASES that are already tagged with their own RFIDs. UHF Radio Waves do not pass through water and other liquids so it is important to organize pallets of liquids in a way that the tags can all be read successfully.

Having boxes and pallets serialized isn’t really all that helpful unless the receiving party knows what products are in each serialized box and what serialized boxes are on which serialized pallets – oh and which contract they are associated with. Accurately conveying the structured data about the shipment is what allows the DoD to achieve the type of efficiencies promised by RFID. We’ve just described what is called an Advanced Shipping Notice – or ASN.

MATERIALS

Contractors should use paper or polyester RFID label stocks with acrylic adhesives. Since RFID labels are put on Pallets and Exterior Containers users will want to have some degree of water protection. One way to achieve this is to overlaminate. There are many types of RFID inlays. So long as the tag meets EPC Class 1, Gen 2 criteria and once applied to the container can be successfully read from at least 15 feet away.

GEARING UP FOR RFID

There are two primary methods for achieving RFID compliance. The first is to bring everything in-house. That means buying software and equipment and getting trained on how to produce and manage RFIDs in-house. The second option is conveniently called “Slap-and-ship”. In “slap-and-ship” compliance RFID production is outsourced thereby eliminating high up-front investments and eliminating the need to manage a new technology. To produce RFIDs in-house the following minimum requirements: A printer for UHF RFID’s; Software to produce RFID Tags; Blank RFID Tag stocks; and (assuming the printer is thermal transfer) Thermal Transfer Ribbon. The ability to read the RFID data set is also highly recommended with a UHF RFID reader.