X-ray inspection system takes quality assurance to a new level

Inspecting food in jars is particularly difficult because every jar is different in every detail. Nevertheless, foreign bodies must be reliably recognised. The French supplier „Ferme des Peupliers“ produces twelve million jars of yoghurt every year. For product inspection, it relies on a new split-beam X-ray inspection system from Mettler-Toledo.

Located in the heart of Normandy since 1947, the farm „Ferme des Peupliers“ has developed into a recognised brand. The company uses traditional methods to produce Dairy yoghurts and desserts. It regularly receives awards for this at the leading French trade fair for the agricultural sector, the „Salon International de l'Agriculture‘. The natural yoghurts with and without a fruit layer are sold in jars. The company management wanted to Quality assurance and decided in favour of an X-ray inspection solution from Mettler-Toledo.

The main objective of the new, and by all means considerable investment Quality assurance solution should, of course, be to maintain the good Brand reputation of Ferme des Peupliers. At the same time, partners and consumers should benefit from the additional product safety through standardised quality assurance standards.

Ferme des Peupliers has more than 40 yoghurts on offer. There are also two different Filling sizes, namely 125 and 180 gram jars. The challenge was therefore to find an inspection solution for each production line that could detect impurities such as glass and glass residues. Metal fragments in liquid yoghurts - some of them with a fruit layer - can be reliably detected. The use of a standard metal detector was not possible due to the Product moisture and the density of the Glass packaging not possible in combination with aluminium sealing.

Two X-ray beams ensure reliable detection

At this point in particular, Mettler-Toledo was able to point to tests that had already been carried out with this type of glass container and machine. This was a key reason why Ferme des Peupliers decided in favour of the offer from the specialist for Measuring and precision instruments and the installation of a X3730-system. This X-ray inspection system is not affected by temperature fluctuations and has two horizontal X-rays. This opens up two different application possibilities: On the one hand Foreign body - Even glass-in-glass contamination is reliably detected, while the fill level of the jars is visually inspected.

„Even after more than 24 months of use, we are still amazed at the inspection quality and safety offered by the X3730.“
Edouard Chedru, Co-Manager of Ferme des Peupliers

Mettler-Toledo also scored points because it has its own Project management interface for the French customer. „Mettler-Toledo has supported us at every stage of the project and continues to assist us with fine-tuning to find the best possible settings for our production. We appreciate the team's responsiveness and availability,“ praises Edouard Chedru, co-manager of Ferme des Peupliers.

Split beam function increases detection sensitivity

The X3730 was integrated directly into the production line. It guides the products to be analysed by means of Side-to-side transfer from the main conveyor line to the X-ray conveyor line and back again. The X-ray solution with split beam function increases the Detection sensitivity, by x-raying each jar twice per pass. As each pack is inspected from two different angles, there are virtually no blind spots. Foreign bodies can be detected in any position - even at the bottom of the jar. The Aluminium sealing on the lenses has no influence on the detection sensitivity. The 360-watt system installed at Ferme des Peupliers checks the glass despite the high X-ray absorption rate of glass can currently fill 150 jars of 125 grams or 120 jars of 180 grams per minute.

The challenge of glass inspection

Glass is particularly suitable for packaging dairy products. It is also 100 per cent recyclable. However, glass packaging is a challenge for quality control. This is because the thickness of the glass walls can vary by up to 20 per cent depending on the production process. Furthermore, inclusions and glass strands inside the container, known as bird swings, harbour an additional risk of contamination.

Glass containers differ in their density and chemical composition depending on the product, which influences the absorption rate for X-rays and thus reduces the detection sensitivity of the inspection system. The more complex the shape, the more demanding the product inspection. Glass and metal fragments can be hidden in areas that are difficult to access. A typical example of this is the inner edges of glass containers with a curved base, such as milk bottles. The type of product to be packaged and its viscosity also have an influence on where foreign bodies are most likely to occur.

With so many influencing factors, the X-ray inspection solution, the conveyor system and the ejection mechanism must be precisely tailored to the application in order to achieve optimum inspection results and a low false reject rate.

Now that the new systems have been in use for two years, it is clear that the potential of the Inline inspection technologies are fully utilised. Foreign bodies are better recognised and product quality has been improved. Even the Production efficiency rose.

Processes are constantly being optimised

The strategic investment decision was also based on the experience of other companies, reports Edouard Chedru. „We wanted to ensure the integrity of our products while maintaining our traditional production methods.“ This has been successful: „This approach offers maximum security for the Stakeholders of our sales channels - such as supermarkets and local distribution - and opens doors to new markets such as Asia,“ says Chedru with satisfaction.

With the operation of the new inspection facility, Ferme des Peupliers has laid the foundations for a continuous Optimisation process the yoghurt and Dairy dessert production laid down. Best practice experience from other dairy product manufacturers was also used as a guide. Edouard Chedru finds the data provided by the X3730 helpful: „We can learn a lot from analysing the data collected by the new system, especially when it comes to rejects by defect type.“

Find out more about the product inspection solutions from Mettler-Toledo here.