Manufacturers know that costly production and sequencing errors can be prevented by carefully tracking components, parts and assemblies throughout the manufacturing process. The dificulty lies in execution. Bar codes provide accurate, eicient identification and can assist with product genealogy data, but bar code symbols are not viable in many common industrial processes. Wireless radio frequency identification (RFID) is an excellent alternative to bar codes, but this technology has traditionally had its own environmental challenges. Most RFID systems are highly sensitive to interference from metal, which has limited RFID use for manufacturing tracking applications.