Tim Ansell, sales director of Dubai-based Al Thika Packaging, explains why he is convinced that X-ray inspection has a strong future in the Middle East.

Although X-ray technology currently enjoys only a limited share of the product inspection market, as manufacturers begin to understand its advantages and realise its suitability for different applications, many more of them are beginning to embrace the technology.
X-rays started making inroads into the food industry in the early 1990s. The driving force behind this was the increasing number of foreign bodies which could not be identified by metal detectors. Other than contaminants like glass, bone, rubber, stone or plastic, some specific applications are also more challenging for metal detectors, such as fresh meat and poultry, or foil-wrapped products.
Another benefit of the X-ray is its ability to carry out other types of inspection, including component counting, the identification of misshapen parts, and mass and zoned mass verification. Also, compared to other inspection equipment, it is relatively immune to product effects and similar physical interactions, including:
• the effects of metallised film and foil packaging. In fact, X-ray   systems can inspect aluminium and steel cans
• the presence of metallic items, such as premium inserts,   pouring spouts, clips, etc
• the effects of conductivity or polarised molecules, and    products produced in brine or similar conductive liquids
• temperature. Products to be inspected at temperatures    between -20°C and +90°C
• vibrations from surrounding equipment
• the proximity of metallic objects, magnetic fields or    conductive materials.

The role of the metal detector
Apart from the cost implication of installing a new inspection system, the main reason behind the enduring prevalence of metal detectors is that, for many manufacturers, they remain an effective “first line of defence.”  If there is minimal risk of non-metallic contamination in the product, a metal detector will consistently and accurately identify the most likely foreign bodies – swarf, filing, nuts and bolts.
Similarly, due to more rigorous demands from their customers and legislation, many food processors require inspection systems at various points on their production lines. Often these will be early on, for incoming ingredients; after mixing/immediately prior to primary packing; and just before dispatch.
So, if it can detect metal and do so much more, why have manufacturers not replaced their metal detection systems with X-ray?

Fear of the unknown
Some manufacturers, whose processes are suited to X-ray inspection, have concerns over installing new equipment. There is a perception that it is difficult to set up and operate more complex technology. In fact, the opposite is true. X-ray technology is surprisingly simple – the machine looks for objects that are denser than the surrounding food or beverage product. With a simple user interface and touch-screens, the equipment is also very easy to navigate.
The safety of the equipment is also a subject of discussion when considering X-ray inspection systems. X-ray beams (which are electromagnetic rays, as are microwaves and visible light) are contained within the machine and do not pose any risk to human health or safety. No protective clothing or equipment is required, and no impact on health has been found among operators who have used X-ray machines for extended periods of time.

Installing the right inspection equipment
The choice of inspection equipment is based on many variables, including the product itself, its packaging material, the potential contaminants and, of course, budget. As a result, it is advisable to speak with suppliers who offer a range of solutions rather than only one product. It is not uncommon for food manufacturers to have three or four different machines installed at different positions on the line. A gravity fall metal detector or bulk flow X-ray machine to inspect incoming raw materials may be followed by a vertical packaging detector between weighing and bagging. Then, after a checkweigher, an X-ray machine or metal detector may be employed to check the case-packed product.

Understanding how X-ray works
X-rays are generated by a heated filament creating a stream of electrons and directing them towards an anode, which is embedded in an angled plate. When an electron strikes the anode target, an X-ray beam is emitted and directed down, out of the X-ray tube.
The beam, which is fan-shaped, is directed towards an X-ray detector. This is normally a line of photodiodes positioned under the product conveyor. As the product is transported along the conveyor, it passes through the X-ray fan beam and absorbs some of the x-rays. As a result, fewer X-rays reach the detector than left the generator, and the detector measures the level of X-rays that pass through the product. Each photodiode (pixel) measurement is converted to a grey level value. The pixels are then combined, line-by-line, into a coherent, formatted image, showing areas of different density, which is analysed by a built-in purpose-designed computer.
Where products display density or mass variations outside the parameters specified by the user, a reject mechanism removes them automatically from the line. Many X-ray systems can inspect with belt speeds of up to 80 metres per minute in the food industry – and very high inspection rates are possible (depending on product specifications) with market-leading equipment such as Mettler-Toledo Safeline‘s GlassCheK (1,000 jars or bottles per minute), CanCheK (1,200 cans per minute)  and AdvanChek (500 packs per minute).

Starting to work with X-ray
There is no doubt that X-ray inspection has considerable advantages in many food and beverage processing environments. Easy to install, safe and simple to use, even without previous experience, X-ray offers comprehensive contaminant detection and much more. It quickly and consistently identifies substandard products, reducing product recall, customer returns and complaints, therefore protecting manufacturers’ brands. It helps them demonstrate due diligence and comply with HACCP and other industry standards, retailers’ QC requirements, and national and international regulation and legislation. The use of X-ray can improve customer confidence, satisfaction and retention and assist in the generation of new business.
With all these benefits on offer, and reassurance about installing and using X-ray systems, the future is looking bright for this innovative and exciting technology.
Al Thika Packaging specialises in end-of-line packaging and inspection systems and has been the exclusive Mettler-Toledo Safeline distributors in the Middle East for more than 10 years.
Mettler-Toledo Safeline is the world’s leading supplier of metal detection and X-ray inspection solutions for the food and pharmaceutical industries. Together with Garvens checkweighing, Mettler-Toledo Safeline forms the “Product Inspection” division of Mettler-Toledo.