Auto ID is a general name for technology used to identify specific components. For example, bar codes are an easy way to identify what product you are purchasing. You can use a Radio Frequency (RF) tag on a pallet to tell a work station what assembly is entering the work station.
There are many different ways to perform auto ID. We typically work with bar codes, RF ID, magnetic cards and the oldest method, printing.
Bar Code
Bar codes are in use everywhere from the grocery store to security systems. Bar codes are easy and inexpensive to use. The most common problems are temperature extremes and dirt. Most people now have experience with bar codes since almost everything we purchase has a bar code label that is scanned at check-out. Most of the advantages and disadvantages you see while making purchases carry over to manufacturing. However, note that these bar codes are designed to last for a short period of time and to be used once. If you label a pallet, storage bin, tank, or other device you might expect that bar code to be read many times over several years. Bar codes become less reliable the longer they are exposed to the real-world environment. Another disadvantage of the bar code is that it use to contain very little data -- a single number -- that referenced a database. This has changed since there are now 2D (dimensional) bar codes that can store much more data and are more reliable. However, they are more expensive to read and print.
RFID
Radio Frequency "tags" are small enclosed devices that when in range of a read / write device will communicate. RF tags can be read-only or read-write. These tags are more rugged than barcodes and are typically placed on pallets, machine tools, and other items. The tags are not very expensive but the read / write heads can cost thousands of dollars (read only heads being less). Tags are designed to be reusable.
Magnetic Stripe
Most employee badges now have magnetic stripes that allow them to use building access security systems. We sometimes use the same badge to log in / out an operator at a machine.
Printing
Printing is still an option and is sometimes combined with a bar code. For example, the status of an assembly can be determined and then a label can be printed and applied to the assembly. Newer advances do not require labels. Three methods we have used are laser, impact and ink jet printing. Note that these are industrial printers -- not office printers. Laser printers fire laser beams that burn the characters into the surface. These are used a lot in pharmaceuticals and semiconductors. With impact printing you fire metal rods to create a dot matrix character. The inkjet printers fire drops of ink in precise locations to form characters.
See Also
Auto Id Links