For big stores like Wal-Mart or any other agency that involves large number of people and requires maximum security, how they monitor the goings and comings of every product or person makes for a very interesting study.
Good thing someone invented the bar codes. Since every merchandise has a bar code on it, shoplifting has been avoided, if not minimized. Airports and car-rental companies and even NASA rely on bar codes for easy tracking and monitoring.
These kinds of codes however have flaws—line-of-sight requirements and the inability to write additional data to a bar code. Probably seeing this limitation, Harry Stockman invented the RFID tag.
Radio frequency identification (RFID) tag is a small object that can be attached to or incorporated into a product, animal, or person. RFID tags contain silicon chips and antennas for them to receive and respond to radio-frequency queries from an RFID transceiver.
The key feature of the technology is the ability of an RFID-tagged object to be tracked instantly from anywhere in the world, provided that a reader is in range. The main application for this today is tracking products along a supply chain. Everyone in the RFID-enabled supply chain, from the manufacturers at the factory to the inventory trackers at the retail location, has the ability to instantly call up the location, condition, and supply of a particular product. (Read more: The Future Is Here: A Beginner’s Guide to RFID)
Knowing the extent of the use of RFID, it’s only proper that Six Sigma be utilized to ensure 100% of use. Simply put, when we receive a data read, it must have Six Sigma reliability.
RFID reading can be unrealiable for two reasons: the interrogator’s RF field is not uniform and is even distorted by the mere object in the field (environment) and nearby. Because of these, if you introduce the same tags over and over again, you will run the risk of missing one of them at any given time. If multiple tags are in the field and you read them, you cannot be certain you actually read all of the tags.
To solve this problem, you must know how to read one tag reliably. What are the limits—in terms of speed, distance, attenuation, orientation, interference, etc., of your ability to read a single tag? Once you have answered that question, you have the raw material for a successful implementation of a Six Sigma RFID system and can look forward to automation with assurance and confidence of high reliability.
Below is a sample case study.
Case Study 1: A number of items (with tags) are on a shelf, and you want to do an inventory.
If you merely want to scan the goods as a bulk audit, then you can sweep the reader in the area of the products and record the tags. This method is good only for a general information record. You have no certainty that you have read all tags and should not assume you have. To read the items reliably, you must assure that the RF field includes only the number of items you know to be in the field (be careful, though—if you cannot see a field and merely aim it at a tag does not preclude reading its neighbor). In this case, you may sweep the tags at full power so the interrogator can get a general idea, and then at a lower power, operating closer to the items of tags, so that the interrogator can read them individually.
So why is this better than bar codes? Time-and-motion studies will show it to be significantly faster because you do not actually need to find the tag and observe it visually.
Read more: Six Sigma and the Single Tag
