Steed Webzell reports on the latest marking and reading innovations designed to help meet increasing traceability demands in the manufacturing sector.
Strict product liability laws and shrinking margins are forcing more transparency in production processes. As a result, the call for 100% traceability for all components is growing louder. In turn, component marking ensures that every part is given a distinct identity, similar to a fingerprint. But, according to laser marking specialist, Trumpf (0844 482 0188), a targeted traceability 'back to roots' is only guaranteed, if the coding is readable with a high degree of security.
Image: Data matrix code marking, courtesy of trumpf technology
The barcode has been used extensively in the past to mark components, but Trumpf insists that manufacturers quickly come up against the limits of this coding. Information density, for example, is one limitation. This is a growing phenomenon and not only in sectors such as automotive. Shortened life cycles, growing model variety,, and design and production-specific changes are characteristics of nearly all products. At the same time, development is moving steadily in the direction of miniaturisation, so there is simply little room on many parts to place a barcode.
Putting a lot of information in a tiny area with modern laser technology is anything but witchcraft. For example, lasers enable a 24-digit code to be placed in a 2 by 2 mm area. In particular, data matrix code markings can be read with a high degree of security, due to error checking and correction operations. Regardless of the angle under which they must be decoded, even when 20% of the marking is obliterated, the necessary traceability information is not lost, says Trumpf.
ORDER BOOK BOOSTED
The ongoing popularity of laser marking systems is seemingly assured, as confirmed by another specialist in this area, Electrox (01462 472400), which announced earlier this year that the company's order book had risen to nearly £2 million, its highest level since the start of the global financial crisis back in 2007.
Contributing to the growth has been a significant order from a white goods manufacturer in Turkey, although Electrox has also seen a rising trend towards replacing, rather than repairing, laser machines. Electrox's general manager, Paul Mincher, says the trend is being driven by the significant reduction in the capital cost of laser machines over the past 10 years, many of which have reduced in price by almost 70%.
Image: Companies can mark large, heavy components with greater accuracy and speed with FleXYZ workstations
One of the company's latest developments is the enhanced FleXYZ workstation, which allows companies to mark large, heavy components with greater accuracy and speed – around 25% faster. The unit can cater for components of up to 600 by 600 by 200 mm, and up to 160 kg in weight. The FleXYZ is compatible with all Electrox laser marking systems, from the low-cost Raptor to the high-specification Scorpion Rapide. It provides motorised solutions and programmable X, Y and Z axes, using Electrox's Scriba software. There are two lenses to choose from: 163 and 254 mm, which provide marking fields of 140 and 218 mm diameter respectively.
Laser marking has found itself many niche areas of application and among these is production of graduation marks on measuring devices. However, while pocket-sized rulers and micrometers are fairly easy to manipulate, what happens if the instrument is a 3 or 5 m Vernier caliper? This task is extra challenging, because all measuring tools must fulfil certain industry standards defining admissible tolerances. And with measuring units of 0.01 mm being common, these tolerances are in the micron range.
According to laser marking machine manufacturer Rofin-Baasel (01327 701100), standard laser marking systems are generally not configured to meet this combination of large physical size, coupled with micron accuracy. Galvo marking heads are fast, but limited to marking fields in the range of 100-200 mm in length.
An industry-standard alternative approach is to use precision motorised axes to manipulate the workpiece. This solves the size issue, but the problem then becomes cycle time. For a caliper of 1 m in length, the laser marked lines on its scale can add up to more than 20 m. Positioning with motorised axes alone would take too much time, resulting in an inefficient production process.
Image: Marking large calipers is difficult, but is made much easier with Rofin-Baasel technology
MAKING BIG MARKS
Rofin, however, has a solution for such challenges. A massive granite-based machine weighing 7 tons was recently delivered to one of its customers. The construction of this system is highly resistant to temperature change and vibration, allowing it to meet the stringent tolerances required. High resolution X/Y axes move the workpiece precisely within an area of 2,650 by 300 mm, while an unusual double galvo-head system with beam switching completes the set-up to achieve a positioning accuracy better than 2 micron within a marking field of 1 m in length. The set-up also features a rotary axis for marking cylindrical parts.
From the big to the very small, and the even smaller: with the new G3 workstation from FOBA, high precision and repeatable laser marking and engraving of small workpieces is achievable. Available from Kaye-Dee Marking Solutions (0114 256 0222), the 2-in-1 laser processing machine belongs to FOBA's line of laser engraving machines, but bridges the gap to FOBA's all-laser marking machines. For even smaller parts, FOBA is also involved in a project that claims excellent micro-machining and marking on brass and aluminium, using a newly developed pico-second laser system. The Germany-based project is led by a team from Laser Zentrum Hannover.
Industry has put a long list of requirements on micro-machining laser systems – the beam must be easy to focus and non-fluctuating, while the need for beam re-alignment has to be minimal. Fibre-based pico-second lasers, which replace solid-state, free-beam laser set-ups – the result of the PULSAR research project – fulfil these requirements.
The system is adaptable to different settings, not least because the laser oscillator and amplifier are separate. Also, depending on the material and the process requirements, the repetition frequency and average output are easy to change – making rapid optimisation feasible.
Of course, not all traceability requirements centre on laser marking. According to Laurent Boucher, director of group sales and marketing at Pryor Marking Technology (0114 276 6044), the company has been extremely busy in alternative systems development.
"While we have developed laser solutions, we also have new dot peen models that are extremely compact and fast, powerful scribing systems, and integrated field-bus systems," he says. "We have also developed a suite of software for data capture to traceability applications."
Another marking specialist with a pedigree for both laser and non-laser systems is Technifor (01926 884422). The company's latest development is the XF530m portable deep marking system: a quiet unit that uses a domestic electricity supply and can be positioned on the component without clamps or positioning tools. The device has a marking field of 200 by 50 mm, can mark texts in various font types, logos, dates and variables, and can mark in a flat, angled or radiating way.
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Trotec acquires Identify
Adding to its recent acquisition of Suregrave, Trotec Laser Ltd (0121 327 5301), a member of the Trodat Gmbh Group based in Austria, has now purchased Identify Engraving Systems Ltd (0117 953 0800).
Although Identify will continue to maintain the Epilog range of laser systems it has supported since 1996, the company will now sell Trotec lasers, the latest addition to which is the Speedy 300 flexx. For the first time, a CO2 and a fibre laser source are integrated into a single Speedy system. This leads to multi-faceted applications, freedom and flexibility for the customer: a CO2 laser source is well suited to engraving plastics, wood, rubber, glass, leather and many other materials, while for engraving and marking metals and for achieving colour change on plastics, a fibre laser is the preferred tool.
Image: The Speedy 300 flexx sees, for the first time, a CO2 and a fibre laser source integrated into a single Speedy system
