Clear lessons

Following the recall of millions of hazardous toys, total product traceability must be a key requisite of modern day distribution systems. Colin Carter reports

Marking and traceability have recently been in the news with the recall of millions of Mattel‘s Chinese-made toys, some containing hazardous small, powerful magnets and others containing excessive levels of lead paint. If all the toys cannot be traced the legal costs could be astronomical, and the company’s reputation would be further damaged.

The giant Toys ‘R’ Us chain has also had to recall sets of Chinese-made crayons and paints because the packaging of the wooden boxes contained lead. And the Chinese themselves have discovered microscopic nematode worms in packaging of goods from the US as well as ‘sub-standard’ vitamin and fish oils.

It’s not just toys though. Bags of spinach from California were recalled when it was discovered that some batches contained traces of salmonella.

Clear marking is obviously a key requisite of modern day food distribution systems and EU regulations have been in force from 2006 to ensure this. According to Nadine Hansen of Linx Printing Technologies: ‘While most food packs already include traceability information, it is now essential to be able to trace information right back to the source of a problem, should the need arise. If there are any issues with the packaging, the food company needs to be able to pinpoint exactly from which supplier the pack came.’

She explained: ‘Once the pallet or case is broken down, information about an individual pack’s manufacture can be lost. There are, of course, a variety of ways in which these details can be stored and accessed if needed but a simple discrete manufacturing code on the pack, using UV ink or laser technology, would help simplify this part of the traceability operation.’

Laser marking is very popular for everything from metals to labels and there are many manufacturers offering this in various configurations for specific applications.

Joshika Akhil of Laser Quantum, manufacturer of CW green, blue and infrared diode pumped solid state lasers — including single frequency and stable high-power visible lasers — explained: ‘We feel that laser marking and etching is the preferred technology across industries which require precision techniques. The technology is being used for marking and anti-counterfeiting applications in many areas including diamond marking, subtitling, bar-coding and invisible encoding.’

She said that holographic marking is increasingly becoming more popular as an anti-counterfeiting measure, not only for security purposes but also in more domesticated applications such as brand authentication.

‘With recent trends towards heightened security measures there will soon be a demand for better traceability of every component in most common domestic products,’ said Akhil. ‘We have already seen this introduced through new packaging traceability laws in the hospitality industry.’

SPI Lasers manufactures a range of optical fibre-based lasers for applications which include cutting and welding as well as marking, and the company has recently launched a new 10W pulsed laser for marking in high-volume single applications areas. Others in SPI’s range are designed for the marking and micromachining markets and were, in some cases, over-specified for simple applications.

Tyco Electronics, meanwhile, offers a closed loop ytterbium-doped fibre laser system designed for marking flat label materials as well as direct marking of metallic and plastic substrates. The system — which is software controlled and can handle many configurations — is able to mark just about everything from plastics and resins through to stainless steels and hard materials such as titanium and carbides.

Rofin-Baasel has announced a new system aimed at marking pre-coated and heat-sensitive materials such as vehicle parts with painted or lacquered surfaces. The company’s StarDisc laser operates using a multiple pass process designed to mark previously problematic components such as car and truck bodies.

One area where there is a legal need for traceability is medical instruments, which have to be traceable under legislation brought in to help reduce the number of CJD cases in 2000. Meditrax, specialising in providing traceability services for healthcare industries, provides computerised tracking of individual surgical instruments by laser marking and identification.

The company employs a couple of Pryor Marking‘s laser systems to mark instruments as small as 2mm with unique 2D matrix markings. Pryor’s Absolute Readers can ensure instruments are in sets, typically 60-70, for autoclaving and cleaning and ensure they are delivered in the correct sets to hospitals.

Laser marking is not the only option for medical instruments however. Technifor offers a data matrix marking option, made using ‘Micro Percussion’.

Of course, once the items have been marked there is often the need for an automated system to recognise the marks. Vision sensors are especially good at recognising defined patterns such as numbers and are used extensively. One example is top New Zealand ice cream manufacturer Tip Top from Auckland, where a challenge was presented when the company decided to remove the barcode from the lid of its packaging.

To avoid packaging mix-ups the company installed a vision system — which can identify the packaging in variable light conditions — using Cognex In-Sight sensors with the company’s PatMax pattern matching solution.

This indicates the different ice cream packages and can avoid product recalls through potentially hazardous mistakes such as preventing ice creams containing nuts from reaching people with nut allergies.

So, if manufacturers across all sectors are to ensure their products are fully traceable in the event of future recall they are, as can be seen, spoiled for choice.