X-ray Inspection puts Certainty into Product Consistency and Brand Promises

There's more to x-ray inspection than detection of contaminants. The technology that can identify foreign bodies can also spot a huge range of product faults from missing components to compromised seals. Niall McRory, Regional Sales Manager for Europe at Mettler-Toledo Safeline X-ray, believes that manufacturers now have the technology to close the door on product variations. They can almost guarantee the promise of their brand.

How much jam should there be in a doughnut? It's an intriguing question. Most people won't know the answer until they bite into one. That's when they discover that the centre is delightfully red and jammy – or disappointingly bare. The outcome may well determine their future choice of brand.

More to the point, how does the doughnut-maker know how much jam the doughnut contains? They know how much should be there, but they can't see inside, so they have no idea if the next doughnut will delight or disappoint.

Tricky problems like this of quality control have challenged manufacturers for decades. Now, after 20 years of rapid development, x-ray inspection systems can give a definitive answer – and in a fraction of a second.

Taking quality control to areas where human eyes and electronic sensors cannot reach

Since the early 1990s, the food and pharmaceutical industries have used x-ray inspection systems to catch common product contaminants such as metal, glass, stone, bone, and high-density plastic or rubber. These industries were early adopters of the technology because they understood the value of brand reputation and the costs of bad publicity. To prove the point, a 2007 survey by Harris Research* showed that more than half of consumers would switch brands in the event of a product recall.

As the technology has improved, so have the analytical methods. Sophisticated image recognition and analytical software can now examine a single x-ray image for a range of product faults from breakages to missing components to faulty packaging. The result is quality control so precise and so accurate, it can detect a single missing tablet within a sealed carton containing four layers of pharmaceutical blister packs.

Making sense out of shades of grey

All objects and materials absorb x-rays. The rule is that denser materials absorb more x-rays than less dense ones. On a digital x-ray image, dense objects show up as dark grey, while less dense ones appear light grey. The overall result is an image in varying shades of grey.

By examining the image for areas that are darker (ie more dense) than their surroundings, the software detects anomalies such as a stray shard of glass in a jar of baby food. By comparing images with known good ones, the software spots products that fail to meet quality standards. The baker can at last catch the doughnut that contains too little jam because its x-ray image appears too pale.

From this simple analytical technique comes unexpectedly sophisticated quality control. The digital x-ray image is a window on an endless list of hidden product faults: the burger that's not appealingly circular; the garlic loaf that has too little garlic butter in one slot; the contact lens pack that's missing its instruction leaflet; the coat that's lost a button; the box of heart-shaped chocolates that contains a broken heart.

Protecting product integrity at high throughputs

Speed and exhaustive checking rarely go together. In manufacturing, one usually comes at the expense of the other. But not with x-ray inspection systems. Depending on the product and the checks being performed, the equipment can remove faulty products from the line at speeds up to 1,500 units an hour.

As soon as the product passes through the x-ray beam, the software goes to work, often performing several analyses in parallel…searching for contaminants…looking for missing components…checking the integrity of the packaging. If the product fails on any one count, it's ejected from the line.

Multiple inspections of this kind put brand owners in control of their brand values in a way that was unimaginable 20 years ago. In the past, consistency of quality and presentation relied on visual inspections and statistical analysis; now manufacturers can prove that every single product meets the standards they've set themselves.

X-ray inspection ensures compliance with standards such as HACCP

Meeting one's own standards is one thing; measuring up to someone else's requires systems and proof. And here, too, x-ray inspection helps manufacturers comply with external yardsticks – legislative and regulatory standards such as Hazard Analysis Critical Control Points (HACCP), the Global Food Safety Initiative, and Good Manufacturing Practice, as well as ad hoc standards set by individual retailers.

In this safety-conscious production environment, x-ray inspection is the surest way to prove that a manufacturer is serious about protecting customers and meeting its legal obligations.

A full jar, a square carton, a capped bottle, a promised give-away

The range of product features and attributes verified by x-ray analysis is huge. In every case, the software compares what it sees in the image with what it has been trained to expect.

This type of analysis makes product shortfalls a thing of the past. The software can examine fill levels, perform content counts, and check that the meat, potato, and vegetable compartments in a ready-meal are all properly filled.

By comparing product shapes, inspection equipment can spot if a carton has been crushed or deformed; by examining the image density at the top of a jar or bottle, it can tell if the lid is present; by inspecting product seals, it can tell if particles of product have compromised seal integrity.

The same techniques can verify that nothing is missing: that product literature is in place, that premiums and promotional give-aways are in the pack, and that garments have their zip and a full set of buttons.

No shocks, no surprises – x-ray inspection enforces brand values
The latest generation of x-ray inspection equipment is the great defender of brand values. The technology gives brand owners the tools to maintain quality control and product integrity at every stage of production for raw, bulk, pumped, and packaged products.

By setting appropriate parameters and fine-tuning the sensitivity, manufacturers can investigate numerous quality issues from catching contaminants to checking that a product looks exactly as a customer expects it to look. The product that successfully passes x-ray inspection contains no shocks, surprises, or disappointments. The manufacturer knows that it fulfills its brand promise.