Continental Foods implements seal inspection for pouch packages with powder mixes

Pouch filling and sealing of pudding powder

More than 100 years ago, Jeanne Verelst created the first Belgian recipe for powdered pudding preparation. Today, powdered desserts are still a classic in the Continental Foods range and millions of units are packed every year on state-of-the-art packaging machines. For the automated, 100% quality control of the seals of the pouches, Continental Foods recently switched from vision-based control to SealScope™ in-line seal inspection.

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Continental Foods is one of Europe’s leading food companies with branches in Belgium, Finland, France, Germany and Sweden. The group has recently been acquired by GB Foods of Spain, serving an even larger, complementary market. The food group represents brands that are steeped in tradition and quality, with products that have been used daily in most kitchens for more than 100 years.  Well-known brands include Devos-Lemmens, Royco, Heisse Tasse, Liebig, Aïki Noodles, La Gallina Blanca, Blå Bland and Imperial.

It is for these last two brands that Continental Foods, based in Puurs, looked for a new inspection solution that better detected open or leaking paper pouches. These individual packages are typically packed in a carton of six. If certain pouches are not 100% closed after filling, there is a high risk of contamination further along the packaging line, resulting in production stoppages and clean-up actions. If an open package slips past the quality control and is still delivered, there are additional risks of faster spoilage and damage to reputation if the consumer is confronted with a box with a powder film due to open pouches. Bart de Bont, Engineering Manager at Continental Foods, confirms: “It is extremely important that open or leaking pouches are detected and removed from the packaging line.“

Dust – the enemy of a camera inspection system 

Continental Foods processes the pouches on state-of-the-art HDG rotary pouch machines. Three pouches are simultaneously opened, then filled and finally sealed at different stations. At the end of the line, there is a reject system where defective packages are removed from the conveyor belt. Initially, the seal inspection was handled by a camera system, which analyzed the number of ridges in the seal and -based on this analysis- approved or rejected the pouch. However, the fine dusting powder contaminated the camera lens, resulting in too many faulty analyses with unnecessary rejects or failures to emit defective packages. In order to cleanse the camera lens, the line had to be stopped each time, resulting in considerable production downtime. The camera was also mounted just before the ejector system, which often meant that the response was too late to remove a faulty package.  In practice, the camera was often turned off and then replaced by manual inspection. In order to implement a fully automatic, in-line inspection system, Continental Foods was therefore looking for a new, more robust solution. At the same time, it was decided to invest in a new packaging machine due to increased capacity requirements.

Automatic, 100% seal inspection

Distance sensors are installed on a triplex HDG pouch packaging machine

Distance sensors are installed on a triplex HDG pouch packaging machine

It was the German machine supplier HDG that introduced the Engilico SealScope™ system to Continental Foods in May 2019.  After a presentation of SealScope™ by the Engilico team, it was decided to first equip an existing machine with the Engilico system. The SealScope™ solution consists of specialized distance sensors mounted on the existing sealing bars, the industrial controller that processes all incoming and outgoing data, and the HMI presenting the results in an intuitive dashboard.

When closing and sealing the package, the distance between the seal bars is measured with high precision. This measurement is then compared with a good reference seal measurement. If there are any folds or product in the sealing area, this is instantly detected and SealScope™ sends a signal to the sliding hatch to remove the defective product from the packaging line.

The existing HDG machine used to seal three pouches simultaneously on a single seal bar. Because it could not be determined with 100% certainty in which of the three pouches there was a defect – and therefore in principle all three pouches had to be manually verified or removed-  it was converted into three individual, synchronized sealing bars, each equipped with separate SealScope™ sensors. Switching to just a single pouch per bar, they were able to reject the individual pouch with defect, and no more.

Smooth integration on packaging machines

The cause of defective seals is inherent to the type of product to be packaged: because powders create a lot of dust during filling, the pouches are not always correctly transferred from station to station by e.g. contaminated grippers or because a part of the machine is no longer correctly tuned. As a result, folds may occur during sealing or the seal may be skewed. In addition, the pouches sometimes stick to the sealing bars due to the presence of (vanilla) sugar in and around the sealing area, which then melts on the hot sealing bars.

Initially there was some internal skepticism to whether this sensor-based system would work due to the presence of the powder dust, but it soon turned out that SealScope™ was much more reliable and efficient than the original camera system. After SealScope™ proved itself with extensive real production tests, it was decided to also equip the new HDG Triplex machine with the seal inspection system. This retrofit was carried out at HDG in LindLar, before the machine was installed in Puurs. “We are very satisfied with the service provided by the Engilico engineers and their perfect coordinated collaboration with HDG,” continues Bart de Bont, “The fine-tuning of the SealScope™ system went smoothly and even in the dusty conditions the system continues to work reliably.  The new pouch packaging machine also works much more efficiently than the existing 2012 model. On the new machine we have a rejection rate of 1 per thousand pouches, where on the old machine we often had a rate of 1% to sometimes 5%. “

Better packaging process through SealScope™

Folds in the sealing area

Folds in the sealing area can lead to open or leaking packages

SealScope™ brings another important advantage. Since the sensors are mounted directly on the sealing bars, the condition of the sealing process can also be monitored and tracked.  If rejects of pouches increase at any point in time, it is often because there is something wrong with the tuning of the machine or maintenance is required, such as the cleaning of the sealing bars. Due to the instant reporting and newly gained insights by using the SealScope™ system, Continental Foods decided to clean the sealing bars once an hour. By planning this preventive maintenance correctly, the machine is kept in optimal condition and rejects are significantly reduced.

On the packaging lines, several products with different paper thicknesses are packed, which is no problem for the inspection system. SealScope™ keeps track of all packaging statistics per product type, such as number of correct and wrong packages, total number of checked pouches per hour or per batch and even per operator. This data enables comparisons to be made between operators and packaging machines for different products. Based on the information, it can be determined what are the optimal operation settings and these can be applied by all operators and for all machines.

The installation of the SealScope™ inspection system has both increased production quality and made it more robust. With the old camera system, one person was continuously inspecting the quality of the pouches, a challenging and mentally tiring task that cannot guarantee a 100% inspection.

“Engilico’s SealScope system for the inspection of the seals exceeds our expectations”, concludes Bart de Bont, “At Continental Foods we also strive to exceed the expectations of the consumers by always delivering top quality. That’s why we continuously innovate and invest in our production and inspection methods, so that our products will remain the first choice for future generations”.

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