Sealing defects detection: Vision VS Laser Spectroscopy

Vision and laser spectroscopy technologies are two distinct approaches for identifying sealing defects, both contributing to ensuring the preservation and quality of the final product. The choice between these two technologies depends on the type of defect the manufacturer wants to identify. If the goal is primarily to identify aesthetic defects and/or foreign bodies in the seal, vision technology may be sufficient. However, if one aims to identify the presence of microholes or sealing channels in the packaging to prevent mold formation, laser spectroscopy is the more suitable choice.

Vision Technology

Vision technology employs cameras to detect defects along the sealing of the tray due to foreign materials. These defects can be "aesthetic" ones caused by food particles remaining in the seal during the packaging closure process or materials such as fat in the case of cold cuts, flours, etc., which can create so-called "weak" seals. Aesthetic defects can render the food unsuitable for sale, even if the seal's integrity and thus preservation are not compromised. Identifying the presence of materials such as fat or flour in the seal is essential to prevent the formation of weak seals, which could fail due to stresses during transportation and handling. To detect both types of defects, various types of vision cameras are used; in particular, hyperspectral cameras, once configured to the correct wavelength, can identify points where the seal is contaminated. However, vision technology is unable to identify the presence of microholes in the packaging, which can cause problems such as reducing the product's shelf life, loss of its organoleptic characteristics, and, in some cases, mold formation several days after packaging.

Laser Spectroscopy Technology

This technology has a wide range of applications in sectors such as deli meats, bread, fresh pasta, packaged salads, cheeses, and more. It is particularly useful in products packaged in modified atmosphere (MAP) or containing alcohol, identifying target molecules like CO2 or alcohol that escape from the packaging, indicating the presence of microholes. The difference in pressure between the interior and exterior of the package is not sufficient to release the target molecules from the packaging. The packaging is gently activated through rollers designed to facilitate the identification of micro-holes without damaging the packaging. This method can also contribute to stressing weak seals, thereby preventing the formation of holes in the sealing and ensuring product quality. Laser spectroscopy also prevents mold formation in all fresh products, thanks to its ability to detect microholes that are not identifiable through vision technology.

In conclusion, the choice of technology to use depends on the specific needs of the manufacturer and the main defect found in their product. If the goal is to prevent mold formation, adopting laser spectroscopy technology is crucial. If, instead, the aim is to exclusively identify aesthetic defects, vision technology may suffice. Hyperspectral cameras can be a valuable aid in detecting contaminating material in the seal. The combination of both technologies can ensure a more comprehensive control of defects in saeling and packaging, ensuring optimal results in terms of preservation and product quality.