A vision of tracking and traceability

With strict tracking and traceability regulations in place across industry sectors such as pharmaceutical, automotive, medical device, electronics, food and beverage, manufacturers are looking at the latest in vision technology to ensure production processes achieve the required standards in the most cost effective way

Coding and labelling usually takes the form of alphanumeric codes (e.g. lot details and best-before information), barcodes and 2D codes. Products can be tagged either by a stick-on label or by information printed directly onto them or onto the packaging. Label-free direct marking methods are intended to survive the most unfavourable of production and operational processes, as well as environmental factors. ‘Mark and read’ applications are particularly popular for product identification and traceability in safety-critical industries such as aerospace, automotive and medical instruments. In addition, as barcodes have become mandatory in some industries, their quality needs to be analysed and a number of grading standards have emerged in different industries. Industrial identification is extremely challenging due to variations in mark appearance, uncertainty of part position and high production line speeds.

Off the shelf or custom designed vision systems?

The UK Industrial Vision Association, a special interest group of the Processing & Packaging Manufacturers Association, has members who are vision system manufacturers, industrial vision component suppliers and vision systems integrators and they are well placed to offer advice on the most appropriate product or system for a particular application. One of the most popular code reading solutions is a smart camera, equipped with code-reading-specific software. Easy to install, configure and deploy on any production line, these self-contained, industrial grade vision systems combine a library of advanced vision tools with high-speed image acquisition and processing. Typical examples of these are the Cognex Insight vision system equipped with track and trace software and the Teledyne Dalsa Boa IDR identification and verification camera.

Julie Busby, business development director at MultiPix Imaging, comments: “Healthcare product manufacturers preparing for the coming global traceability standards know a successful transition to mass serialisation of product packaging involves more than simply reading a barcode on a label; all of the data on the label must be verified for accuracy. It is vital that code reading systems provide all of the technical controls needed for FDA 21 CFR Part 11 validation, including secure user authentication and automatic audit trail generation with electronic signatures.”

Smart cameras designed for track and trace applications offer a number of capabilities, including: read 2D and 1D barcodes; verify correct ID code contents; grade data matrix codes during production to detect changes in print quality; verify the accuracy of printed text; detect label misalignment and skew; validate and verify patterns; and compatibility with appropriate industry standards.

Steve Hearn, UK sales director at Stemmer Imaging says: “Verification of the quality of the codes being read has become increasingly important as coding becomes mandatory in some industries. 1D grading usually specifies a minimum contrast for a colour of illumination as well as print quality. For 2D codes there are far more parameters such as axial non-uniformity (how square the grid of cells is), grid non-uniformity (whether the cells are positioned correctly) and fixed pattern damage. With many different grading standards for different industries, it is important to ensure that the code reading software supports the required standard(s).”

While the inherent measurement capabilities of these smart camera systems is obviously of great importance, integration into the process is also crucial, so there is a requirement to support standard communication protocols, such as Modbus and Ethernet/IP, for seamless connection to complementary control devices and illumination systems and for integrating into the factory network. Sometimes, though, the application is too complicated to be handled by the smart camera solutions. Robert Pounder, technical director at systems integrator Olmec-UK, observes: “Code reading on some production lines may require a greater engineering input to solve the problem. This may be to do with speed issues, background colour variations, the need to switch quickly and easily between different product or label types, the need for a greatly simplified user interface, or complications with non-standard interfacing – or even some combination of these. In these circumstances it is often necessary to develop a customised solution to meet the specific requirements.”

Applications in logistics

Laser-based readers have always been the system of choice in logistics operations, but all of this changed earlier in 2011 when Purolator, the largest courier service in Canada announced that vision based readers would replace the laser-based scanners currently used at weighing stations within the company’s sorting and distribution centres. The vision-based system offers significantly faster read rates and can also read labels with more highly degraded codes. With the existing laser-based scanners, operators were often required to pass packages under the scanners multiple times before the barcodes could be read. The vision system has been able to read every label on the first attempt, reducing operator processing time by half, and this has significantly improved both operator satisfaction and overall productivity.

Acknowledgements

The UKIVA would like to thank members Cognex UK (www.cognex.com), MultiPix Imaging (www.multipix.com), Olmec-UK (www.olmec-uk.com) and Stemmer Imaging (www.stemmer-imaging.co.uk) for their contributions to this article.

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