We have used hard-cased tags for on-metal returnable transport item (RTI) applications, and have had great success. Now, we want to explore options to track not only RTIs, but the inventory contained within. Our thought is to have a hard tag permanently placed in order to track the RTI, and we can use software to associate the contents to that tag.
The problem is that we are trying to come up with cheaper ways, since tagging hundreds of thousands of metal RTIs would be cost-prohibitive. An alternative would be to use a printed paper label with bar codes, human-readable fields and an RFID chip to encode the part number, quantity and so on. This could work for plastic RTIs, but likely not for metal. That's why I wonder if I could place some sort of buffer, like a plastic substrate backing, on the metal RTI and then adhere the printed paper RFID label to that backing. If I did this, could I avoid interference from the metal?
I have never seen any company use this approach, but it should work, because the plastic would keep the metal tag antenna away from the metal RTI, thus preventing the antenna from being detuned. But companies typically want to protect tags by encapsulating them within hard plastic. Metal RTIs bang together, and if a tag were to take a direct hit, it could smash the chip or break the antenna, thereby rendering the tag unreadable. Using a hard tag designed for this application would prevent that from happening.
Another thing to consider is that when you purchase tags designed to be used on metal RTIs, the distance between the tag antenna and the RTI is optimized, allowing energy to get behind the antenna and power it up. This provides the longest read range possible. If you use a piece of plastic of a random width, you might not select one that could achieve the best read range. It's also labor-intensive to adhere the plastic to the RTI and to then apply the tag.
My advice would be to purchase tags designed specifically for this application. There will be many exhibitors at our RFID Journal LIVE! 2019 conference and exhibition that offer such tags. You might consider attending the event and speaking to some of them.
—Mark Roberti, Founder and Editor, RFID Journal
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