DMC vs RFID in manufacturing
The increasing discussions and regulations on complete traceability and reliable identification of products is making identification systems an inevitable part in manufacturing. Two technologies have been well received: The Data Matrix Code (DMC) and Radio Frequency Identification (RFID).
In order to choose DMC or RFID for your application, you have to understand the fundamental differences between the two technologies. Both have their advantages and disadvantages, and the wrong decision could have costly consequences. The technology you choose will mainly depend on the object being identified: based on size, shape and the environmental conditions.
DMC camera scanners can already reliably read dot patterns of only 2 by 2 mm, so DMC is suitable for very small products or round surfaces where there is little room for marking on the product. With DMC you can place a lot of information in a very small area. Article or batch numbers, manufacturing or expiration dates as well as other important manufacturing data can be stored permanently on the work piece across all processing steps.
Additionally, the error correction when reading a DMC is very high due to information redundancy and DMC’s error correction algorithm, so that even 25–30% contamination or damage of the data field can be fully compensated.
RFID technology makes it possible to unambiguously identify every item that is equipped with an RFID data carrier. An RFID system in manufacturing consists of thousands of data carriers (also called tags or transponders) and a minimum of one read/write device (usually called a reader) with an antenna.
RFID tags are available in many different designs, some as simple as an adhesive tag, while others can be a hard tag such as a disc, bolt or glass tag. Tags of only a few millimetres in size can be used for tool identification and very large transponders for container identification.
Advantages of RFID are that the tag can be read or written without visual contact with the reader, the tag has almost unlimited rewritability and several tags can be read simultaneously. These features open up new usage possibilities that DMC cannot provide. If the RFID tag is integrated in a pallet or tool and you can’t even see it, it can still be identified, even with the greatest possible contamination.
With the rewritability of the tags you also have the chance to change, delete or supplement the data on the chip at any time. Every production step can be documented, read and written directly on the RFID tag in or on the part. To avoid security issues, data can be encrypted, password protected or set to include a ‘kill’ feature to remove data permanently.
Ultimately, the decision to opt for one or the other technology is always a case-by-case decision.
DMC and RFID do not necessarily have to compete. Sometimes it may be beneficial to have a combination of both technologies. An example of a combination solution is an RFID label with a printed DMC. While the DMC can be read directly on the object with a scanner, the RFID tag fulfils further tasks. Thanks to the special technology, goods can be identified even when packaged. In addition, all relevant process data can be stored on the RFID data carrier and offer added value throughout the value chain.
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