Cessna Looks to RFID for Unlimited Visibility

Jan. 7, 2013 − Cessna Aircraft Co. was founded in 1927, the same year Charles Lindbergh soloed across the Atlantic Ocean. Since then, the Wichita, Kans., firm has sold and delivered approximately 193,500 aircraft-more than any other company in aviation history.

Adam Bradford

As a business that got its start by building something many experts at the time deemed impossible -a monoplane with a wing that would not require supporting struts or braces-Cessna has never been reluctant to embrace innovation. The company is now moving into the radio frequency identification age, using cutting-edge technology to track the precision tools employed at its Wichita metal-bonding facility, where aircraft fuselage, wing and tail assemblies are manufactured. "The ability to get our hands on these tools quickly, get them in the process, get the parts through, was deemed as a critical area of opportunity for us," says Adam Blackford, Cessna's director of process engineering, who headed the transition to RFID.

Prior to the introduction of RFID technology, locating the proper tools for specific tasks performed on the metal shop floor was an inefficient, productivity-sapping task, the company reports. The new RFID system, which began full operation last May, allows tools to be located within minutes. Blackford says he began working on the project in 2010 in partnership with OatSystems, a Waltham, Mass.-based systems integrator. "We are tracking the location of over 1,000 assembly tools, occupying over 50,000 square feet, in our metal-bonding facility here in Wichita," he says.

Seeking Efficiency

Project research began informally, Blackford recalls. "We really just started talking with vendors," he says. "We called probably a half-dozen different RFID vendors and started to understand the technology better-what it could do, what it couldn't do-and had them look at our process with us, and really kind of scope out some potential solutions."

This preliminary research led to the establishment of a cross-functional team drawn from the firm's IT, operations, quality and process-engineering departments. "We formulated a team. We set an objective. We started to really map a process," Blackford states. "We wanted to understand how the tools were used, and what we needed to understand about them to make the process better. We do a lot of adhesive, pressure bonding for structural components on our airplanes,"

Producing metal bonds for wing, fuselage and other panel assemblies requires expensive, sophisticated tools-and a tracking technology-that can survive extreme pressure and heat. "We started looking at this technology, RFID specifically, thinking that it might be the answer-and we found that in fact, it was," Blackford says.

The metal-bonding facility's requirements dictated the type of RFID technology that would be used. "The tools have to go through an autoclave curing process," Blackford says, "so that eliminated our opportunity [to employ] active RFID technology, because the batteries and circuitry inside the active tags couldn't make it through the autoclaves."

As the solution was being designed, the Cessna and OatSystems representatives knew that whatever was eventually deployed would need to meet the requirements of a complex schedule mandated by production lines in Wichita and Independence, Kans., running at different rates. "The metal-bonding process is days long," Blackford explains, "so you have to know when the tool is going to come out, where it's going to be and to get it cleaned up and back into the process flow."

With certain production processes running faster than others, workers had trouble remembering and estimating where specific tools could be located at any given moment. "What we found, over time, was that people in the process, such as operators, schedulers or tool controllers, were spending hours physically trying to track down these tools," Blackford recalls. "Spending all of this time tracking the tools down was taking workers away from them solving problems and getting parts through the systems."

System Components and Configuration

The final system was designed to be easy to use, fast and highly accurate. OatSystems provided a STAR 3000 system from Mojix, an RFID technology developer headquartered in Los Angeles, Calif. Designed to cover large spaces, and built on deep-space communication technology intended to detect very weak radio signals, the EPC Gen 2-compliant STAR 3000 system can read a signal from an excited passive RFID tag located as far away as 600 feet (183 meters), Mojix reports. According to the company, the solution's range is 20 times the coverage of traditional systems.

The STAR 3000 system supplied to Cessna also includes 44 eNodes, autonomously operated RF repeaters designed to excite all EPC Gen 2 ultrahigh-frequency RFID tags within designated interrogation spaces, with an excite range of 30 feet and a coverage area of 2,500 square feet. The overall solution helps to maximize coverage and enhance accuracy without driving up costs. A triangulation signal-detection approach enables a few readers to perform the work of many. "If you get a couple of reads on a couple of different antennas, you can isolate where the tag is and then display it visually on a layout," Blackford states. "It's pretty ingenious, because they've effectively replicated an active tag through the passive technology."

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Ceramic tags supplied by Hong Kong-based Xerafy were specified for all tools that needed to travel through the high-temperature autoclaves. "We had to do some testing," Blackford says. "For validation, we brought in some different tag types and put them through autoclave cycles to see how they responded."

OatSystems provided the system's software, including OAT Foundation Suite 7.5, a middleware platform designed to provide two-way process integration between enterprise applications and real-time information from readers. According to OatSystems, the software captures and normalizes large volumes of sensor data, adding business context and consistency logic for enterprise applications, and providing an immediate and accurate record of process steps and asset movements. The firm also supplied its OAT Asset Tracking software, including tool tracking and visualization modules. The software is designed to provide real-time status updates for assets of any shape or size.

Tool Management

The final deployment achieved the cross-functional team's goal of speed, accuracy and intuitive operation, Blackford reports. Whenever a specific tool is required, a user types the item's unique number onto a keyboard, after which a database matches that number with data supplied by readers mounted above production floor workspaces. The system is then able to provide the user with the last known location of the tool within a 20-foot range. "The technology has become a great productivity enabler for this department," he says. The autoclaves themselves are also portals, he adds, noting, "So we know what time and into which autoclave a tool went into."

The facility's tools come in a wide array of shapes and sizes, Blackford says. "The tools range from a size that would fit on your desk to something that is the size of a small boat, maybe weighing 3,000 or 4,000 pounds," he states.

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The larger tools are stored at or near the point at which they are used. "They're so massive that they need to be on the concrete production floor," Blackford says. Portable tools, which comprise the majority of the inventory, are stored with the help of an automated storage retrieval system linked to a series of racks. "We have some simple cantilever racking we use to put tools away," he states.

Unless already in use on the production floor, tools required for specific tasks are delivered from several storage locations around the facility, and are then placed in a queue lane within a layup room. "The users can then go and pull those and bring them into their work lanes," Blackford says.

In the Future

With RFID now playing a critical role inside the metal bonding facility, Cessna is already looking forward to possibly using the technology in other areas as well. Blackford characterizes the current metal-bonding deployment as a toehold showcasing RFID's capabilities.

"What we have discussed as a future step is using RFID for work confirmation," Blackford says. "Every order has a document-a 'traveler' that goes along with it." Employees are responsible for confirming their work as they complete each step of the process. "We are talking about potentially using RFID in the future to automate some of that confirmation of work," he explains. "We've done some benchmarking, and we think that's an area we could look at in the future."

For now, Blackford says, the metal-bonding facility workers using the RFID system on a daily basis are providing some very positive feedback. "We've heard that RFID is making their jobs easier," he reports. "I've gotten very positive feedback about the results and time saved."

The technology also helps the facility's managers, since in addition to making essential tools easier to locate, it has streamlined maintenance scheduling. "The tools have to be calibrated and qualified on an annual basis," Blackford says. "This is another great aspect of RFID technology; the system now alerts us when maintenance is due."

Blackford credits much of the project's success to solid research and careful planning. Failing to lay the proper groundwork, he says, can easily lead to financial waste and missed objectives. "Because you could overspend, or buy things you don't need in the name of technology," he states, "you've really got to boil everything down to one question: What process will the system solve for your business?"

Adam Bradford