GE-Aviation, the engine-manufacturing division for civil and military jet aircraft at General Electric, recently brought an RFID-based order-tracking system into production, according to Trey Keisler, GE-Aviation’s information management leader for planning and logistics.
According to Keisler, the system is streamlining the company’s internal supply chain between its warehouse in Erlanger, Ky., and its assembly plant in Durham, N.C., while also increasing its accuracy. And given that GE-Aviation has, in recent quarters, received record orders to supply jet engines for new Boeing and Airbus commercial aircraft, the timing couldn’t be better.
In Erlanger, workers create kits of engine parts and assemble them into plastic totes, which vary in size based on the particular kit. The parts are generally small. “They are kitted so that operators on the assembly floor can move quickly [through the assembly process] without having to hunt down small, individual pieces,” Keisler explains. “The kits are basically used for pre-staging.”
Previously, GE-Aviation maintained accurate records of the number and types of kits the warehouse prepared for shipping each day. What it didn’t have, however, was a means for obtaining a quick view of exactly which totes made it to the Durham plant each day.
Workers would apply a bar-coded adhesive label on each tote while assembling them onto pallets for shipment. As they did this, they’d scan the bar code, which contains a unique number (which GE refers to as a license plate) stored in its warehouse management software and used to create a daily manifest of shipments. In a perfect world, Keisler says, all of the pallets in a given shipment made it onto a single truck, which was received in Durham the following day.
Often, however, a less-than-full shipment made it onto a single truckload, and because the manifest Durham received with the truck reflected what was prepared for shipment rather than what was actually shipped, the record was often incorrect. To determine what was actually shipped, Keisler says, personnel in Durham spent a good deal of time running around with clipboards, inspecting each pallet. Using RFID has all but eliminated this manual process, and is currently saving Durham personnel precious time previously spent receiving the kits and bringing them into the production process.
Workers at the Erlanger warehouse now apply bar-coded RFID labels to the totes. Each label has an embedded passive ultrahigh-frequency (UHF) RFID inlay compliant with the EPC Gen 2 and ISO 18000-6C standards, which comes pre-encoded with a unique ID number. An RFID printer-encoder captures this unique ID, then prints the label with a bar code containing a license-plate number generated by the warehouse management system (WMS). The license plate and tag ID numbers are then associated with each other in the WMS. GE-Aviation still uses the license plate numbers because they are utilized for other shipping and production functions.
Two to four totes fit on each pallet, depending on a particular tote’s size. Before placing each tote on a pallet, workers apply a printed RFID label to it and use a handheld scanner to collect the license plate number from the label’s bar code. Then, as each pallet is loaded onto the truck, it passes through an RFID reader portal, which collects the unique ID from each RFID tag. Once the truck is full, the WMS generates an electronic shipment manifest based on all RFID reads collected from the portal readers. It can also report which totes have been labeled, based on the bar-code scans collected, but not loaded onto the truck. These totes will then appear, correctly, on the manifest of the truck in which they are later loaded.
In Durham, the pallets are moved though an RFID reader portal as they are unloaded from the truck. The WMS then compares the tag IDs collected from the readers with the electronic shipment manifest, to confirm the accuracy of the shipment.
Placing the labels on the plastic tote, Keisler says, offers enough of a buffer between the inlay and the metallic content of the kits within the tote to eliminate most RF interference. The portal reader in Erlanger captures more than 95 percent of the tags, he adds, based on comparing the shipment manifest generated by the WMS with successful tag reads.
After the totes are received in Durham, they are stored in an area known as the kitting room. As the totes are brought into the room, they move through a portal that captures each label’s RFID tag ID number. This code is again captured as the totes are later removed from the kitting room, providing Durham with a real-time inventory list of tagged totes in the room. Once the totes are empty, they are returned to Erlanger, where the labels are removed before the totes are reused. This is the same process previously employed with the bar-code-only labels.
GE-Aviation began a pilot test of the system in late 2006, then decided to make it permanent in December. Keisler declines to name the RFID hardware and software vendors involved.
This is one of many RFID systems GE-Aviation has tested or deployed. The company began tagging spare parts shipped between its Flight Support Center in Lynn, Mass., and the Erlanger distribution center in 2005 (see GE Aviation Finds Value in RFID).
Keisler says the company has also begun testing an active RFID system for tracking high-value tools inside a Cincinnati research and development facility. The hardware, he adds—which consists of active RFID tags that communicate over the facility’s existing wireless LAN and software that maps the location of tagged tools in real time—may be made permanent later this year. If so, the company will initially track hundreds of tools in the facility.