An explanation of how 2D bar codes can benefit tracking and tracing of consumer packaged goods throughout the supply chain, including a quick overview of recent advances that simplify integration and operation of 2D bar code readers.
Data matrix codes bring manufacturers plenty of benefits without adding a lot of cost or complexity to manufacturing lines. These 2D codes can help marketers create a range of variants such as regional packages and holiday specials, while also providing detailed tracking information that can aid in recalling isolated products or packages that must be recalled or speed responses when problems arise.
Data matrix codes have been used in automotive and aerospace manufacturing for years, but they’ve only recently begun seeing use in packaging and other areas where there’s a need to store lots of information in a small space. The benefits are so significant that some analysts say companies may fall behind if they aren’t using these codes for data tracking.
The symbols can be printed on the components of a product, providing serial numbers that track them throughout their entire lifetime. That can be extremely important if recalls arise.
Data matrix codes can be changed quickly to respond to changes in production techniques or materials. Codes can be altered each time materials or small components are changed, or even when they come from different suppliers. If any of those materials or components prove defective, manufacturers can pinpoint the units that may have problems.
Companies can then target products that have potential problems, saving plenty of time and money. Suspect products could be pulled before problems arise, potentially preventing the high cost and bad publicity that comes with product-wide recalls.
Data matrix codes also help vendors cope with the need to supply many versions of a product, adding a layer of protection by automating inspection. For example, lip gloss, body lotions and other that have SPF ratings for sunburn protection must be properly labeled. With 2D codes, those ratings can be easily detected with comparatively inexpensive readers. Previously, matching labels to the right products required pricey and complex machine vision systems were needed to check the human-readable labels.
In many markets, the codes can augment conventional UPC codes. The 2D images don’t have to be registered like the bar codes that must be read by machines outside the manufacturer’s control. Of possibly greater importance, they hold far more information.
Storing data along both the height and length of a symbol lets them hold more than 3,000 characters, although most component verification applications use 10-14 characters.
This storage capacity can also provide a big payoff in manufacturing processes. A code can tell equipment operators or automated systems which component is coming down the line. When similar-looking products require different drill bits, for example, the 2D code can store the information, dramatically reducing the likelihood that the wrong size hole will be drilled.
Adding 2D coding to a manufacturing system doesn’t require a huge amount of time or add great expense. Readers and lighting systems are less demanding than those used for machine vision systems, and the relatively small amount of data means that control systems don’t have to have nearly the computing power required for automated vision systems.
Advances in 2D bar code readers
One of the keys for any optical code reader is lighting. In many applications, readers with built-in illumination fill the bill, so installation is straightforward. One example is the Siemens SIMATIC MV420.
The compact reader has built-in illumination and can achieve operating distances of up to 30 cm – subject to ambient light and conveyor speed. This greatly reduces the costs that would otherwise accrue with an external illumination. For more complex applications, the MV420 has a fast trigger output for easily controlling an external light in synchronization with the image capture.
Frequently, a wide range of operating distances needs to be implemented, depending on which product is to be packaged or processed with the machine. Here, flexibility is important. When readers have high-quality integrated optics, they can be adjusted to different object distances by simply rotating the lens barrel. That’s another benefit of MV420, one that eliminates the need to order and stock various models in order to implement different object distances.
The reading result is normally reported to a controller or a central server. More complex tasks may also require the handling and depiction of the results by a visualization component (Human Machine Interface, HMI). The integration into the higher-level automation systems is often very complex and may require special hardware converters and programs in the controller or the visualization component. However, this step can be minimized when readers have software and hardware that’s ready to use.
This can dramatically shorten setup time. In many instances, operators simply need to aim the reader at the right area and enter various parameters such as system speed before they can start production.
Ease of installation and a high cost-to-benefit ratio are driving a rapid expansion for data matrix codes. A growing number of retail packages sport them, and fields like pharmaceuticals are also making extensive use of 2D codes. As usage grows, the knowledge base for system integrators will continue growing, making it easier for companies to install systems and begin reaping the benefits of data matrix coding.
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