Reliable, non-destructive leak testing of coffee packaging
The food and packaging market is facing major challenges: longer transport routes and growing demands on products today require better shelf life. In addition, there are increased demands in terms of environmental compatibility, legal requirements and consumer wishes. In order to fulfil these criteria, it is necessary to carry out leak tests on packaging during production to prevent leaks and damage. These tests ultimately serve to ensure product safety and consumer protection such as in the case of vacuum-sealed coffee capsules and packaging. Here, manufacturers attach particular importance to brand-relevant quality features such as freshness, color, creaminess and aroma and flavor intensity.
Expertise in the food and packaging industry
Established suppliers of leak testing systems have proven to be reliable partners for coffee producers. With its extensive expertise in the food and packaging industry, INFICON, for example, has tried-and-tested products for this application in its portfolio. The easy-to-use systems are used where quality requirements are particularly high: for coffee packaging. “This is not least due to the special properties of the popular hot beverage,” argues Arman Khazali, Operations Manager at Italian coffee manufacturer and INFICON customer Bialetti from Coccaglio, in the province of Brescia. According to Khazali, coffee is a luxury foodstuff that, like wine, is based on a raw material. Due to natural influences, such as the climate or soil conditions, the fruit is not identical for every harvest.
Test tolerances ensure product quality
“To ensure our product quality, it is therefore important that we have established valid test tolerances in production”, explains Arman Khazali. These include, for example, the quality of the roasting, i.e., the uniformity of the beans, color and integrity. “Another criterion concerns a uniform degree of grinding with a certain proportion of powder, which we ensure,” emphasizes Arman Khazali. “Last but not least, we focus on the efficiency of our production machines during assembly and packaging”, adds Khazali.
Added value through non-destructive leak testing
Plant manager Arman Khazali puts Bialetti’s annual output at 180 million coffee capsules and 2.9 million soft packs. And because these products are exposed to high water pressure during the brewing process in the coffee machine, a leak would impair the delivery into the cup and therefore the quality of the coffee. According to Khazali, the main focus of an
intelligent leak test must therefore be on accuracy and the ability to provide a numerical quantification for each test in order to carry out a statistical analysis. “In addition, non-destructive testing offers added value compared to a destructive test,” reports Arman Khazali. “Other advantages are the significant reduction in testing time and the fact that we are autonomous in terms of personnel and can therefore produce 24/7.”
Fast, reliable and non-destructive
Bialetti has only recently switched from destructive water bath testing to the non-destructive method. This is why Bialetti has been testing its product quality with leak testers from INFICON’s Contura S400 series. With the help of the applied pressure increase method (see below) in the flexible test chamber, both the smallest and largest leaks are detected quickly, reliably and without test gases. “The INFICON system therefore makes a significant contribution to the consistent quality of our capsules and packs,” says Arman Khazali. At Bialetti, the process extends to three automated lines for the assembly of capsules and one line for the assembly of soft packs. A total of 60 employees works in Coccaglio. The production includes roasting machines, automated lines for capsules and soft-pack assembling, automated machines for coffee makers assembling and die-casting press.
Longer minimum shelf life for food
The testing process with the mobile Contura S can be easily integrated into production: During evacuation of the test chamber, two flexible membranes enclose the test objects so that they remain intact. If there is a leak, gas from the packaging penetrates into the evacuated test chamber causing a measurable increase in pressure in the vacuum of the chamber. Gross leaks and micro leaks of less than 10 μm are detected in seconds. Thanks to the Pressure Increase Method, the minimum shelf life can be increased.
User-friendly color display
The user-friendly touch display of the Contura S is a major benefit for Bialetti: “It shows the relevant test results and information in color at a glance – and an acoustic signal can also be heard,” reports Arman Khazali. The display also shows the exact leakage rates for the set time interval, giving users a quick overview of the quality of the coffee packaging.
Full support from INFICON
“All in all, INFICON not only gave us full support with the Contura S, but also with its sales and technical team,” says Arman Khazali, pleased with the well-coordinated cooperation. INFICON has also demonstrated its technical expertise and reliability with tests, results reports and analyses. “Building on this, we can very well imagine further joint project work between INFICON and Bialetti in the future. And why shouldn’t we expand our production capacity on this basis one day?” says plant manager Arman Khazali, looking confidently to the future.
Excursus: Non-Destructive Pressure Increase Method
To detect leaks in packaging, various methods can be employed, such as bubble bath or CO2 testing. The common principle among these methods is the creation of a pressure difference between the test object and the surrounding environment. This pressure difference forces any contained gas to escape through leaks. The higher the pressure difference, the smaller the detectable leaks. However, high pressure can damage the seals and packaging, which may lead to misinterpretation of results, as intact packaging might rupture and be mistakenly identified as leaking (picture attached).
Additionally, traditional testing systems like bubble baths are highly dependent on the user and must be adjusted differently for each volume and type of packaging. The results are recorded manually, and all tested samples, whether they are found to be intact or leaking, must be disposed of after testing. This practice harms manufacturers due to high write-offs and impacts the environment by causing food waste and additional avoidable waste.
In contrast, the Contura system measures leaks using a pressure increase system within a flexible film chamber. It is very easy and quick to operate: simply place a test item in the chamber, close it, and the system automatically evacuates to 30 mbar while the membrane protects the packaging from expansion and seal stress. The system then uses highly precise, self-developed and produced pressure sensors to detect potential leaks, providing you with a non-destructive and reproducible result in less than 15 seconds.
the reliable Contura system calculates a quantifiable and reproducible leak rate in mbar*l/s from the pressure increase and the time. No other provider has mastered this process. The device therefore not only shows whether something is leaking or not, but exactly how tight it is. This happens regardless of the type of leak or the number of leaks.
A major advantage: the measurement is non-destructive, which means that packs that have tested negative for leaks can be sold or leaking packs can be repackaged and the pressure difference between packaging and chamber Is the by far highest on the market.
www.inficon.com