HEAT-SEALED PACKAGES INSPECTION

Quality failures in packaging

Hermetic containers (MAP, EMAP, vacuum, skin, …) preserve the freshness of the product and preserve contact with the food atmosphere. It is essential to ensure that the container is heat sealed effectively, since otherwise the product loses qualities and perishes before the date of preferred consumption. This represents a serious quality failure and may be the cause of rejection of an entire batch of products.

To guarantee the quality of the container, the surface of the sheet and that of the tray must be perfectly clean in the welding area, since any type of contamination will make it lose its tightness. As a result, air and contaminants like mould, fungi, or bacteria can reach packaged foods and contaminate them.

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Packaging inspection by machine vision

With conventional vision systems it is not possible to see through sheets printed with inks, so its field of application is greatly limited. This type of inspection is not effective in cases where the weld area is invaded with transparent products, such as the interleaver that is used in slicing or the melted fat, which is colourless. They also use image comparison methods within the visible light spectrum, being ineffective in packages with printed films where defects are usually confused with printing inks.

In other words, conventional vision equipment is insufficient to guarantee the quality of the welds and is ineffective in the case of using films with different printing inks.

Chemical image packaging inspection

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Hyperspectral vision technology developed and patented by INSPECTRA for the inspection of containers, allows analyze the heat-sealing region detecting contamination by transparent elements even through sheets printed with opaque inks, processing the images of the containers captured in different frequency bands of infrared light, allowing us to the detection of 100% of the failures that occur in the sealing of the containers.

Our technology allows detecting, for example, contamination in different types of ham sliced packaging, where it is inspected, contamination by fat, lean or interleaver in the welding area.

These applications are tailored to each type of packaging and each product, and are independent of the colour of the sheet printing ink. The hyperspectral vision also allows to characterize the chemical composition of the surface of the packed product, allowing to detect the presence of foreign bodies, and the classification of the product according to the presence of chemical compounds (for example lean/fat, humidity, …)

INSPECTRA, allows to combine hyperspectral vision technology with other linear vision systems to analyze other quality parameters of the container, such as the correct positioning of the sheet with respect to the tray, the Code printing verification or any other verification carried out by conventional artificial vision systems.