Smart partnering for a high-tech titan

For years, the company has experimented with RFID, but early in 2003 it embarked on its RFID compliance adventure by generating its own study on the benefits of RFID implementation in the supply chain, then created a smart partnering strategy to get there.

This company had developed an expertise in tag types, read ranges, tag placement and automating RFID into production and distribution processes. It has built up an RFID practice among its customers in the manufacturing arena, supporting deployment to comply with the Wal-Mart mandate of January 2005.

Partners for a pilot
In deploying its own RFID systems in the retail supply chain, the company started a pilot programme in January 2004. Turning to other RFID experts, it established dynamic partnerships in a go-to-market strategy combining robust software with end-to-end services.

Working closely with several middleware providers to integrate RFID into its existing system, the company set the groundwork. For RFID label printing, the project selected Printronix Smart Label Printer Applicators to tag cases and Smart Label Desktop Printers for pallets. Though initially only a few of the many consumer products the company ships to Wal-Mart were EPC-tagged, the entire range of consumer products sold in the stores will soon be readied for tagging.

RFID challenge
Various contract manufacturers package the company’s pilot products at several plant locations. Given the wide variety of products produced, a facility gave products with a one-to-one relationship to the package, or products with a many-to-one relationship. If the product has a one-to-one relationship, the tag is placed on the outside of the sales floor packaging. If it has a many-to-one relationship, the tags are placed on the outside of the master cartons. Both situations require a manual application of RFID labels to each pallet, but the faster moving lines require automated encodeprint-and-apply process for applying RFID labels to cases.

Solution system
Together, the middleware and Printronix RFID hardware address EPC and RFID requirements to tag both individual pallets and high-volume, high-speed conveyors of cases, before being shipped to select distribution centers.

The company needed a solution that could accommodate reliable encoding of tags by Rafsec, Omron and Alien. Early in the pilot, the company utilised the Printronix SL5000e MP RFID printer for printing RFID labels on cases. When Printronix expanded its SmartLine printer family with the SLPA7000e in June 2004, the company conducted extensive review and demonstrations to outline their automation requirements with its capabilities. The company selected the SLPA7000e for its ability to encode, verify, print and apply multiple sizes and EPC classes of RFID labels, and its competence in preventing application of bad tags to cases. A set-up interval occurs between production orders to accommodate case size changes, product size variations, and the changing application heights and distances of the SLPA7000e resulting ad rates. The product’s shipping pallets are manually labeled with pallet tags encoded and printed with the SL5000e MP. The Printronix printer uses a multi-protocol UHF encoder (compatible with Class 0, 0+ and 1 tags) to encode multiple tag classes and sizes.

Extensive testing was done on label sizes, RFID tag read rates, and tag types. The exact location and size of the label was critical because of the existing package graphics and geometry of the single item case. Labels from Rafsec, Omron and Alient were eventually selected given the existing shipping label size requirements and read ranges. The original Printronix RFID printers the company installed did not initially support all selected tags, but due to the flexible and modular design of the SL5000e, the company easily updated their printers with the tag suppliers’ support via an update.

How the system works

Step one
In multiple production lines, flat, collapsed, cartons are automatically placed on a conveyor, formed into shape by a case erector, and then filled with product. By experimenting with the tag placement on the carton, the company learned that if a gap existed between the product and the place on the carton where the tag was attached, they could avoid many interference problems. Even so, work continues in order to achieve 100 percent read rates with the cases on a shipping pallet. The full case is then packaged by taping the case shut, and a barcode is printed on the box. Like other Wal-Mart compliance suppliers, the company will continue to use barcodes in addition to RFID tags. Barcodes are used to identify products as they move through the supply chain, as well as at the retail level, and act as a human-readable backup, should it be required.

Step two
The cases activate a box sensor attached to the conveyor, and trigger an ‘event’ in the SLPA7000e ’s General Purpose Input/Output (GPIO) to apply an encoded label. The GPIO is a Printronix input/output device manager, designed to enhance the ability to send and receive signals to and from a materials handling system or external device, to complete complex tasks such as system alerts, driving multiple applicators.

As the SLPA7000e receives a signal, it advances a 96-bit Class 1, RFID label to be verified, encoded, printed and applied to cases as they move down the conveyor. Conveyor speeds are approximately 20 boxes per minute. If the SLPA7000e detects a bad or ‘quiet tag’ as the label advances off the roll, an attempt is made to encode several times over the course of a fraction of a second. The bad tag is then over-struck for easy identification, and advanced on the rewind wheel for analysis. This feature provides users traceability of bad tags. It also eliminates the user intervention commonly found in less sophisticated mechanical arm reject designs.

Step three
Tagged cases move down the conveyor past an external reader for re-verification of label application, signal strength and read-range of that label. If the case does not have an RFID tag, the case is rejected and diverted off the conveyor into a reject bin for rework. Cases will subsequently be sent down the conveyor a second time for re-application of tags.

Cases with verified, (good) labels move down the conveyor to an accumulation conveyor. Here the cases are stacked on pallets; shrink-wrapped and transferred to a new conveyor. At this point the SL5000eMP desktop RFID printer prints a batch of Class 1, 4" x 6" labels with EPC numbers. These labels are applied to the finished pallets to complete the labeling process. Pallets are moved to dock doors for final verification. An Advanced Shipping Notice (ASN) will be sent to the Wal-Mart distribution centre.

On the other side
When the tagged pallets and cases arrive at Wal-Mart’s distribution centre, readers at the dock doors automatically scan the tags. The data passes to an application that will alert the company, along with the retailer’s operations and merchandising teams that the specific shipment has arrived. Cases are removed from the pallet and processed as usual, then trucked to the participating Wal-Mart stores.

When tagged cases arrive at the back of these stores, the tags on the cases will be read and automatically confirm the arrival of the specific shipment. Signs featuring the EPCglobal logo are placed at the shelf where the company’s products are sold to help customers identify tagged items. Understanding and appreciating consumer privacy concerns, the RFID tags do not contain nor collect any additional information about consumers, and do not track customers after the product leaves the store.

Conclusions
In May, 2004, the company began shipping EPC-tagged products to Wal-Mart’s Dallas/FortWorth distribution centre as part of the retailer’s trial. As the implementation expands, the company sees RFID’s potential to drive significant gains in productivity. The company concluded that a pallet of one of its products ready for shipment could be processed in just 11 seconds – down from the 90 seconds it had taken previously. It is understood that in electronics manufacturing there is a high degree of variability, where every item could mean a shift in configuration. But the company realises products can be shipped and received more quickly, making RFID development worthy of pursuit.

During 2005, several more SLPA7000e printer applicators and SL5000eMP printers will be installed. The company continues to share its growing knowledge of RFID to its business divisions and manufacturing partners.

The good, the bad and the quiet
A label is considered good when the RFID data is written to the tag correctly, the correct image is printed, and content data is verified against the source and the tag can be read at an expected distance. If the printed and encoded data can’t be verified against the source, the label is considered bad or defective and voided from the system. To ensure that no EPC numbers are lost, the printer can be programmed to clearly overstrike and void the defective label and print another label using the same EPC data. When an encoded tag can’t be read from a normal distance, it’s called a quiet label. In some cases a quiet label may be the result of a defect in a specific label within a roll of good labels.

Print/encoding systems should be designed to identify quiet labels and to void and overstrike them, removing yet another source of error. A quiet label needs to be eliminated from use to achieve 100 percent read rates.