Lately, it seems that everyone is interested in the answer to this question: Is RFID the same thing as bar-coding? I find that quite intriguing because there are still many manufacturing companies that use paper travelers that are manually initialed after each process step is complete, as well as paper pick lists for both raw materials and finished goods picking and order fulfillment. In many instances, human readable labeling or instructions provide a valuable secondary process confirmation beyond the systematic use of bar coding or RFID (radio frequency identification).
Does bar coding do the same thing as RFID? The answer: Many of the same things can be accomplished with bar coding as with RFID, but the methods required to accomplish each will vary.
Let's look at a few of the basic differences between bar coding and RFID that will affect how you would use each technology in your operation.
|Bar-coding Versus RFID|
|Bar Codes ||RFID Tags|
- Require line of sight to scan bar codes
- Can only scan and read one bar code at a time
- Can be scanned from 30 or 40 feet away from label
- Scan accuracy nearly 100%
- Can scan several hundred scans per minute with no reduction in throughput or line speeds
- Cannot scan an entire pallet of case labels without breaking down the pallet and rebuilding
- If a specific license plate label (a reusable tote) is lost, you must visually inspect all labels to find the correct one.
- Don't require line of site to read each tag
- Can scan many RFID tags simultaneously
- Scan/read distance limited to a few feet for low-cost, passive tags*
- Scan accuracy of 100% can be achieved, but difficult
- Dwell time required to scan all tags on a pallet or a tag on a case traveling on a conveyor can reduce line speed and throughput.
- Can scan all cases on a pallet with single pass through a portal reader
- Can read and locate a specific RFID tag (attached to that same tote) more quickly
*Active RFID tags can transmit signals over a much greater distance due to their internal power source. As you start to consider the differences from a technical standpoint, you begin to see how the differences will cause process changes to be considered. If you have a high speed packaging line and you are attaching bar-code labels, it is easy to print, verify and apply a bar code label to each item or case at very high speeds. Of course you would still need some method of verifying misapplied labels and diverting those items off of the line for re-labeling. If you try to accomplish the same thing with RFID, you may require several label printer/tag encoders for the same line speeds. You would have two (or more) for the same line that would label every other item/case as it passed by in this scenario. This is further exacerbated based upon product type, packaging materials, plant humidity, local RF interference and a variety of other factors that would impact how many RFID labels/tags could be applied each minute and verified for readability. In a finished-goods warehouse using a warehouse management system, case labels with bar codes would be associated systematically with an outbound pallet license plate (bar-coded) label. The systematic association happens as the picker scans each case label as he/she stacks the case on the pallet. Just before shipping and after the pallet is shrink-wrapped, a pallet label would be printed and applied to the pallet. With bar code labels, this would require manual application of the labels and the scanning of each label before stacking it on the pallet to confirm the pick. In contrast, with RFID labels already attached to cases and a mobile reader attached to a forklift or pallet jack, the system is simply updated by placing the case on the pallet and allowing the reader to confirm the pick automatically by reading the RFID tag. In addition to speeding up the picking process, RFID has the added benefit of auto-printing/encoding the pallet label and having the integrated human readable label/RFID tag printed and ready for application as the picker approaches the shipping dock. Further verification of pallet contents can be done with RFID as the pallet is loaded on the truck to ensure that the customer is getting exactly what he expected. There are many more examples of how you can achieve the same results with bar coding versus RFID tags, and they will be addressed in future issues. Each technology has its strengths and weaknesses, and in many cases can be complementary depending on the problem that manufacturers are trying to address. Chris York is a principal with Raleigh, N.C.-based Tompkins Associates, a global supply-chain-solutions consulting firm. Chris has more than 15 years of experience in the design and implementation of supply chain planning and execution systems, collaboration and visibility solutions, FDA validation and regulatory compliance, AIDC/RFID, TQM, ISO9000, warehouse and TPM in a variety of industries.