RFID in the Warehouse and Distribution Center


The UHF passive RFID revolution began in
the warehouse. Long before there was item marking in retail, before races were
being timed, before RFID enabled access control took hold, there were tags being slapped on pallets and cartons in the warehouses of
consumer goods manufacturers in preparation for shipment to Walmart
warehouses around the world. The early carton based compliance programs never
matured, as at that time the technology was not reliable enough. in the Delta of
value, the barcoding on cartons and cases was not wide enough to continue on that
pathway. But, times have changed. With today’s 100% read rates, passive RFID is
generating massive amounts of data and creating real efficiencies in the warehouses of today. Let’s take a look at some common applications. Even five years ago, encoding large numbers of tags on a high-speed conveyance line was next to
impossible. However, with the improved sensitivity of today’s Alien Higgs-4 and
Higgs-EC tags, hundreds of individual item tags inside a carton can be
programmed instantly with a unique EPC as it moves past the reader and antenna.
Even on a conveyor moving at 500 to 600 feet per minute or faster. What’s more,
the system knows the type and quantity of items which are to be within each
container, so that if a stray item is included or missing, the container can
be sent off to the rejection shoot. Many apparel manufacturers have established
their own serial number methodologies, so the encoding of tags quickly has become
a critical piece of the retail supply chain, which is now driven by tagging at
item level. Aggregation is the means by which
several tags are associated to a single tag. A typical warehouse management style solution entails item-level tags getting abrogated or identified to case tags and
case tags, in turn, getting aggregated to pallet tags. When a series of tags are
aggregated to a single tag, this series of tags are known as child tags while
the single tag is referred to as a parent tag. Upon reading a parent tag at
any given RFID checkpoint, all of its associated child tags are deemed to have
also been read at that checkpoint. What are the core benefits of aggregation. One-
you don’t have to read every tag. When large populations of tags pass through a
single checkpoint. By reading the parent tag, you are, in essence, reading all of
its child tags Two- when doing inventory cycle counts of goods, be it with handheld scanners or with a mobile, fixed reader configuration, you don’t have to
read every item-level tag to reconcile every item in a case, and you don’t have
to read every case level tag to reconcile every case in a pallet.
aggregation is an excellent RFID solution design approach that helps
enable 100% reconciliation of goods, even if 100% read rates of all your RFID tags
is not possible. Thus, your RFID Hardware implementation doesn’t have to be perfect, particularly in difficult environments. This method
lessens the expense of implementation while providing significant benefit over
barcode based solutions. Turning a negative return on investment
into a positive ROI could be in tracking individual cases on a pallet. The best
way to read all these cases on the pallet would be to have the interrogation station with RFID readers on the shrink-wrap or collar wrap
station. The best way to set up this station would be to install antenna on
both a fixed location next to the pallet turntable and another on the movable arm
dispensing the shrink-wrap. When the pallet is spun on the turntable, the
movement on the tags both on the cases and the individual items within assist
in the readers penetration within to ensure accurate and comprehensive
results. Once the pallet is stretch wrapped, an aggregated tag for that
pallet is generated, allowing a single designation to represent all items
contained within that pallet. The last step out of the warehouse or distribution center is through the dock doors. This is one of the most common
applications for RFID technology. The reader and antennae are typically
incorporated into a portal system, which focuses the RFID interrogation to a narrow region, typically by the outgoing or incoming dock doors. Your inventory or
ERP system knows what you are expecting to ship to your customer or receive from
your supplier. As the pallet passes through the RFID portal, the items
identified on that pallet are compared against your shipment record. If the records do not match, an exception is generated which can alert personnel via light stack
or audible alarm. The shipment contents could then be corrected to ensure
continued customer satisfaction, reduce costs due to making up for incorrect
shipments, and correct inventories for both customer and supplier.

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