Making sure your favourite chocolate is in the box

How does technology ensure your favourite chocolate is in every box — and that each doughnut contains just the right amount of jam? Dr Richard Parmee, of Sapphire Inspection Systems, explains.

Opening a box of chocolates to discover your hazelnut favourite is missing would be very disappointing. But just think how much worse it would be if you opened a box of regular medication and some of the tablets were missing or incorrect.

It’s all too easy to take for granted that a product we buy will contain what it says on the box. After all, factories have had strict inspection processes on production lines for decades to ensure that items ranging from food and beverages to medicines and cosmetics are free of foreign bodies.

But the latest X-ray inspection technology can do so much more than detect a fragment of metal or glass in a box of fish fingers or a packet of tablets.

Has a product got the correct amount of filling, for example – and is it evenly distributed? Are there any missing or damaged items in a multipack? Are there dangerous bubbles of air in a drug-device combination product? All these questions – and more – are now being answered in real time, without disrupting traditional factory procedures.

The latest technology can be used to check the mass of a product to ensure it meets weight requirements. But it can also check the individual masses of a series of items within a pack, which is how it can tell if a box of chocolates has the right chocolates in the correct positions – and that each doughnut is filled with the right amount of jam. It can also detect and reject a steak pie with less filling than the others in a pack, even if some of the others have slightly too much filling.

The inspection settings can also be optimised for the different zones within packaging. A chocolate chip cookie, for example, contains relatively dense pieces of chocolate – so the contaminant parameters for that section of a biscuit box insert will need to be detuned. The zone containing rich tea biscuits, however, has no such requirement, so maximum sensitivity can be maintained.

Image processing software also provides the tolerance levels required to deal with the variable shape and thickness of glass containers. The technology can cope with the thick glass often found at the base of glass jars, along with tapered shapes, ridges, and bulges. It can detect shards of glass within glass cosmetic containers, for example, as well as checking that bottles are filled to the correct level.

The presence of bubbles in a fluid within a container can also be detected. The bubbles might be unwanted if they affect the quality of the product or if the packaging has an aerosol attachment. It can also detect where bubbles might be required, in a mousse, for example. In each case, product quality can be confirmed.

Checking there are no extra, missing or incorrect tablets in a sealed blister pack on a high-speed factory production line is an interesting challenge. The latest X-ray systems combine low-energy X-ray imaging with active pixel sensor technology to achieve high sensitivity – with resolutions 10 times greater than traditional end-of-line X-ray machines. That means they can detect not only missing or broken tablets (with an inspection zone created around each tablet pocket) but also contaminants such as metal, even though the products are packaged in metallic blister packs.

The technology can even detect paper inside cardboard using adaptive algorithms, and check that each box contains a leaflet giving instructions for use, which is a regulatory requirement. Quality checks can also be performed on drug delivery devices such as autoinjectors, ensuring the needles are in the correct position and that other parts of the device mechanism are within position tolerances.

As we increasingly rely on factory production lines for all aspects of our lives, it’s good to know that a new generation of X-ray inspection technology is keeping an eye on things.

Dr Parmee is a Cambridge Angels member and founder and CEO of Cambridgeshire X-ray inspection technology pioneer Sapphire Inspection Systems. The company, based in Litlington, has specialised in X-ray inspection technology for 40 years, and has close links to the University of Cambridge.

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