RFID

While this article exaggerates a bit, the fact is that the bar code is the first successful auto-ID technology, so successful in fact that more advanced technologies, like RFID or even QR-codes, have yet to displace it. There are barcodes on Kanbans, but you really cannot say that the system depends on them, because Kanbans were used early on without barcodes more than two decades.

The 40th anniversary of the barcode is an opportunity to remember, or learn, who invented it and why. This article does not credit the actual inventors, Norman Woodland and Bernard Silver, who patented it in 1952, but only supermarket executive Alan Haberman, who made its use practical to improve inventory tracking and speed up checkout. In 1974 he led an industry committee to adopt the barcode as a vehicle to implement a Universal Product Code or UPC. It is as much the story of the emergence of a standard as a story of technology.

In Manufacturing, barcodes are used almost everywhere to identify warehouse locations and stock keeping units, to validate picks, and to track component serial numbers. While celebrating the success and the usefulness of this technology, we should, however, remain aware of its limitations. Even in supermarkets, barcode reading remains a largely manual process. A human still has to wave around small items in front of a reader, or a reading gun in front of large items, and it often takes multiple attempts before you hear the beep confirming a successful read.

Fully automatic barcode reading is occasionally found in manufacturing operations where the environment is clean, with good lighting, high contrast, and a controlled orientation. QR codes are less demanding. They can be, for example, etched on the surface of a metal workpiece, and read inside the work enclosure of a machine-tool.

RFID tags hold the promise of full automatic reading at a distance. It has made them successful in public transportation passes like the Octopus card in Hong Kong or the Navigo card in Paris, as well as in electronic toll collection in the Fastrak system in California.

Barcodes are also limited to IDs and cannot be updated. As a consequence, they have to be used in the context of an information system that contains all the data keyed on the ID, which can be “the cloud” in a supply chain, or a local manufacturing execution system in a factory. By contrast, a high-end RFID tag can locally contain the entire bill of materials of a product moving down an assembly line, its current location in the process, and any measurements that may have been made on it at earlier operations. For a finished product, it can contain the entire maintenance history of a unit.