RFID Heats Up Production at U.K. Boiler Factory

"The greatest priority was controlling the process," Sainsbury states. If a mistake were made (for example, if a step in the assembly was skipped), it would be caught only at the end of assembly, when the product was tested. Rectifying that error would require taking the piece of equipment back through the assembly station where the slip-up occurred, and making the necessary corrections—which, he says, was a time-consuming process. "If one element [in the assembly process of a piece of equipment] was missed, and it wasn't found until the final test, we lost time and efficiency—time that could've been used for assembling."

With the RFID system—which was installed in February 2010—the Vaillant Group has been able to reduce errors by removing the decision-making process from the assembly staff's responsibilities. Instead, the company utilizes an RFID-enabled automated system to track when each task is completed, and to allow the next station to become operational only if all tasks have been completed at the prior station. Electronic tools that provide feedback to the company's back-end management system are used in conjunction with RFID readers, so only the correct boiler can activate the subsequent station. In addition, the system can detect mistakes and ensure that no further assembly takes place, by showing a failure in the process to the station's operator and not allowing progression until all necessary work at that station has been carried out.

A Power-ID battery-assisted passive UHF EPC Gen 2 RFID tag was attached to two opposing legs of each trolley.

With the RFID system, the company attached a battery-assisted passive ultrahigh-frequency (UHF) EPC Gen 2 tag, provided by Power-ID, on two opposing legs on each of 20 trolleys. Vaillant Group needed the system to read tags quickly and send data to the assembly-management system (AMS), which would then permit the powering of tools only if the trolley ID number indicated the proper chassis had arrived at the station. The battery-assisted tags provided that quick response time from the reader. The company had tested passive, active and battery-assisted systems, Sainsbury explains, and had selected the battery-assisted solution as the most accurate. "We found passive tags did not provide a high read rate in the highly metallic environment," he says, "while active tags were capturing stray reads from carts passing through other parts of the assembly line."

All boiler variants can automatically be accommodated through reading the RFID tags and cross-referencing against the components being assembled. When a boiler chassis is placed on a trolley, the ID number encoded to the trolley's RFID tags is read and forwarded to the AMS database, where the tag ID is linked to the chassis' serial number. The trolley's tag is coupled with the chassis' serial number for the duration of the assembly process. In addition to the serial number, the AMS database also contains other information, such as the assembly worker's bar-coded ID number, and component items installed on the boiler.