Aircraft Parts Maker to Use EPC Tags to Track Moisture Exposure

By Claire Swedberg

March 18, 2007—Universal Avionics, a flight-management systems manufacturer based in Tucson, Ariz., is about to install an RFID-based system to track how long moisture-sensitive microchip components are exposed to air. Designed by a team of three researchers at the University of Arizona, the system is slated to be put in place next month, at a cost of about $2,000.

Universal Avionics first contacted the researchers in the fall of 2007. "They came to us looking for a solution," says Bonnie Latham, a senior at the University of Arizona majoring in industrial engineering, and the project's lead systems designer. "We were presented with a problem, and they said they saw RFID as being a potential solution."

From left: Jesse Green, Bonnie Latham and Jeremy Wright

To manufacture the circuit boards it makes, Universal Avionics assembles the components and fuses them together through a baking and soldering process. If overexposed to humidity, the components no longer fuse properly when they are heated, says Universal Avionics' material control manager, Brenda Hughes. Some components can tolerate 156 hours or more of contact with the open air before absorbing too much moisture, while others can withstand only about 50 hours. If they near their exposure limit, the parts must be put through the baking process immediately, or else be thrown away.

It is often time-consuming to measure the exact length of time components are exposed to air. In the past, parts have been stored in vacuum-sealed bags identified by means of paper labels. When a bag is opened or resealed, an employee records the time on the attached label.

With the new RFID-based system, Universal will place parts on trays or in reels, then store them in desiccators, also known as dry boxes (provided by TDI International), that use nitrogen gas to displace moisture-filled air. Researchers are attaching a SkyeTek ultrahigh-frequency (UHF) reader complying with the EPC Gen 2 standard to the dry box, using a USB cable to send data to a dedicated computer running software developed by the research team.

Each tray will have an Alien Technology EPC Gen 2 RFID tag attached to it. If a tray is removed from the dry box, the reader will fail to receive a transmission from the tray's RFID tag, and will send an alert to the back-end system, at which time the system will begin tracking how long the tray is outside the box. The software is designed to correlate specific RFID tag numbers with that reader so that the interrogator can send an alert if a specific tag is not present.