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Laser marking addresses evolving traceability needs

Bone screw

Lasers can generate 2D codes and text in even the smallest areas, such as on the head of a bone screw in the medical sector (Image: Foba)

Andy Toms, Director of TLM Laser, looks at the evolution of traceability and highlights the benefits that laser marking has brought to the implementation of regulatory standards across several industry sectors

The concept of traceability has been with us for many years, and although the term may mean slightly different things, depending upon industry sector or product, the principles of being able to verify the true origin of an item, its authenticity, and whether it conforms to any particular set of standards are common objectives. 

There has always been a requirement for some form of traceability within certain industrial manufacturing sectors, especially where products or components are safety critical, such as in the aerospace and medical sectors. Original methods of product marking for traceability purposes were, by today’s standards, very basic and would include manual marking with alpha-numeric punches or dot-peen marking. Similarly, the methods of recording this information would also be largely manual with paperwork, often in duplicate or triplicate, manually archived for cross referencing purposes at a later date.

Although many may be unaware, traceability plays a key part in our day-to-day routines by safeguarding much of the food that we purchase and eat. Many food products, and especially the fresh variety, are monitored and tracked from the point of production, through transportation, storage, and eventually to the supermarket shelf to ensure the produce we are eating is safe. These same traceability methods and procedures makes it possible to implement fast and efficient recall in the event of a product contamination issue.

Today the vast majority of the product and traceability information present on everything from food products, medical devices, implants, automotive components, and safety critical aerospace parts is generated by laser, often in the form of bar codes, or the 2D data matrix codes which have revolutionised product traceability. These 2D codes can contain significant amounts of data, such as date of manufacture, product reference number, production batch codes, serialisation numbering and much more.

Traceability compatible with Industry 4.0 and beyond

Originally, much of this laser marked information was produced predominantly in the latter stages of manufacturing, and often as the last process. Today however, manufacturers across many different sectors are striving to increase levels of connectivity within their production processes, by implementing smart manufacturing initiatives compatible with Industry 4.0. 

Lasers are now being introduced to generate 2D matrix codes as a first step, allowing a part to be tracked as it progresses through the various different production stages. As the part is presented at each production or machining stage, the 2D code is scanned, verifying initially that this is the correct and expected part variant, and subsequently that the part has passed through this manufacturing operation successfully. In addition, any process parameters associated with the task performed at that stage can also be recorded against the part for quality control purposes.

As any given component moves through the different manufacturing stages such as machining, grinding, finishing and inspection etc., a detailed history of how the part was produced is built up and retained for future interrogation if required. This fast and efficient method of marking parts with a 2D matrix code not only provides an indelible mark but streamlines the process of part traceability.

Traceability on metal components

Laser generated 2D matrix codes enable traceability of the different manufacturing processes used in the production of a part

In manufacturing environments where multiple processes take place, the ability to guarantee that all of the appropriate operations have been carried out successfully on each individual component, provides the highest levels of quality assurance, reducing the potential for product recalls, and also reinforcing the fight against counterfeit products.

In many cases individual manufactured components are then integrated within larger sub-assemblies and final assemblies as part of vehicles or aircraft. In applications where safety critical components require regular operational hour based or annual inspections, as may be the case with certain aerospace components, once again, scanning the 2D code makes it possible to verify that the part has been checked in accordance with requirements.

Also, in the unlikely event of a serious incident or accident, the 2D matrix code makes it possible to retrospectively interrogate both the production lifecycle of a part, together with its associated maintenance and repair records. These same principles and benefits apply in the case of the medical sector, where implants and surgical instruments also need to be both identifiable and traceable. 

The capability of the 2D matrix to hold significantly more information than a conventional linear bar code, combined with the ability of the laser to generate the code in very small sizes and spaces, makes it possible for even the smallest of parts, such as surgical screws, to be identified and traced if required. A further benefit of the 2D matrix code is that even if parts of the code are damaged, it will still be readable by scanners or machine vision systems.

With many industry sectors and businesses now working towards or fulfilling their Industry 4.0 aspirations, the concept of Industry 5.0 is now on the horizon. The European Union definition of Industry 5.0 is described as reinforcing the role and contribution of industry to society through placing the wellbeing of the worker at the centre of the production process. This principle also includes using new technologies to provide prosperity beyond jobs and growth. Just as the laser has been at the heart of Industry 4.0, there is little doubt that the technology will continue to make a valuable contribution to future developments.

The medical sector’s prescription for traceability

The UDI programme (Unique Device Identification) continues to be rolled out with the objectives of facilitating easy and reliable traceability of medical devices, whilst at the same time enhancing the effectiveness of safety-related activities for devices by enabling enhanced monitoring of their status and use at all levels. There are many anticipated benefits from this system including: easier access to recall information, improved traceability of devices of all types including implants, and faster identification of possible counterfeit items. Under these rules, and depending upon risk classes, there is a legal requirement for products and packaging to incorporate a UDI code in both plain text and a machine-readable form such as a barcode or 2D matrix code.

Furthermore, the new MDR regulations may also apply to non-medical devices that are deemed to have a risk category similar to that of a medical device. This is likely to include items such as cosmetic implants and perhaps even contact lenses. In addition to UDI marking, and following Brexit, UK businesses must now start using the new label which replaces the EU’s CE mark. The UKCA mark will be mandatory on certain products and indicates that goods conform to domestic safety legislation. The clarity and durability of the information associated with UDI, MDR, CE and UKCA is key to recognising conformity, and in the case of UDI and MDR, ensuring compliance and ongoing traceability throughout the lifecycle of the item. 

Green laser technology expands marking and traceability opportunities

Foba's latest range of 532nm wavelength "green lasers“, launched last year and now distributed in the UK by TLM Laser, offers marking systems with a low heat impact. These new vanadate laser sources are available with 7 or 14W laser power, and provide outstanding speed and accuracy, especially on substrates that do not exhibit satisfactory marking results using other wavelengths.

Foba Green Laser

Foba's range of green lasers can enhance marking capability even in the most challenging applications

The range of materials include many white and transparent plastics, glass surfaces, highly reflective metals, or combined material parts. In addition, red or orange plastic surfaces, which often only display poor marking contrast, due to their existing colour properties, now obtain perfectly legible codes and characters. On special plastics such as UHMWPE, HDPE or PMMA, the marking quality achieved is just as impressive. The green laser also makes laser compatible additives unnecessary in most cases.

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