Magazine Article | February 1, 2006

RFID Solution Ensures Quality Manufacturing

Source: Field Technologies Magazine
Integrated Solutions, February 2006

The electric motor business is a highly competitive worldwide industry in which Reliance Electric US, a Division of $5 billion Rockwell Automation, continues to thrive despite competitors with Asian manufacturing facilities. Part of this competitive edge lies in Reliance's industrial RFID system from RFID solutions provider Escort Memory Systems, which controls and identifies motors as they flow through the production facilities. U.S. regulations require that each motor have start-to-finish traceability; this requirement is met within the manufacturing lines through the use of durable RFID tags that identify each motor at every step of the build process.

The plant tried other auto ID solutions, ranging from an early RF (radio frequency) implementation to bar codes. After significant experimentation, the best solution proved to be industrial RFID. Reliance decided to go with HMS150 passive RFID tags (operating at 13.56 MHz with 712 bytes of read/write memory) from Escort Memory. The tags are mounted in the base of each motor manufacturing pallet. A unique identification is written to each tag as it enters the manufacturing cycle using an Escort Memory Systems HMS827 reader/writer.

A reader/writer at each processing station automatically notifies the manufacturing host as a motor/pallet arrives for processing. Reliance Electric's WIP (work in process) system then sends the process instructions for that motor to the process tool and operator. The pallet is held at a station until the WIP system confirms that the processing is complete and that the parameters for that operation are within specification. The process data from each step is then recorded into the WIP system database and is associated with the specific motor serial number. Thus, detailed process information is recorded and stored with the serial number for permanent retention. The pallets are recycled after each use and sent back to the beginning of the lines to await the next motors.

The processing details for each of the 30 manufacturing steps required to build a motor often vary based on the requirements of the order. Motors must be scrapped or reworked if any one of the process steps deviates from the specifications. Studies have shown that humans make a mistake anywhere from 0.1% to 1% per operation under ideal situations (no stress). Statistically, a process with 30 steps and an error rate of 1% at each step has a final yield of 74%, or a 26% scrap/rework rate with manual processes.

RFID automation systems such as those used in Reliance Electric's manufacturing plants reduce the error rate to well below the 0.1% level. With the RFID-enabled pallets, Reliance Electric's engineers ensure that motors are not processed until the pallet RFID number, work order number, and associated operation codes are correctly displayed at each process step.