Complete list of aluminum foil pouch inspection items and methods, ready to use!

Aluminum foil bags have good barrier properties, heat sealability, and moisture resistance, and are acid, alkali, and abrasion resistant. Therefore, they are widely used in the outer packaging of clothing, apparel, cosmetics, and food. With the increasing demand for the quality of aluminum foil bags, the quality inspection of aluminum foil packaging bags is becoming increasingly important.

Below, Shunxingyuan Packaging, a professional flexible packaging manufacturer, summarizes how to perform visual inspection of aluminum foil bags, including inspection items such as the flatness and transparency of composite bags. This is mainly used to detect whether there are obvious scratches and pinholes on the surface of the composite bag, and whether there is contamination at the sealing.

1. Aluminum Foil Bag Utilization Visual Inspection Check Quality

Place the composite aluminum foil bag in the center of your hand, align it with a 40W fluorescent lamp and gently shake it. Through the reflected light from the surface of the composite aluminum foil bag, you can clearly see if there are any scratches or marks on the surface of the composite aluminum foil bag, often called "bag surface drawing" in the industry. If the drawing is serious, you should find the fault according to the actual situation, minimize the impact, and ensure product quality. We have observed that the drawing phenomenon is mostly caused by the unclean guiding roller of the bag-making machine, so it is necessary to ensure that the guiding roller is clean. In addition, the non-rotation of the guiding roller will also cause the composite aluminum foil bag to have drawing faults. The reason for the non-rotation of the guiding roller is mostly caused by the lack of oil in the bearing, so good lubrication is the fundamental condition for the rotation of the bearing.

2. Inspection of the Flatness of Composite Aluminum Foil Bags

The specific method is: take several finished bag samples and perform "air-to-ground" dropping, allowing them to land naturally and the landing point must be clean. Observe the condition of the composite aluminum foil bag after landing. If the composite aluminum foil bag bends, curls outward or arches inward when it lands, it indicates that the flatness of the composite aluminum foil bag is poor; otherwise, it indicates that the flatness is good.

The reasons for poor flatness generally include the following points: the bag-making temperature is too high, which has destroyed the stress stiffness of the inner layer of the composite aluminum foil bag; unreasonable structural composition; uneven thickness of the material itself, etc. When the total thickness of the composite material does not exceed 80μm, the flatness is easy to deteriorate.

3. Visual inspection also includes the inspection of transparency

For some products, due to the large area without patterns, transparency is particularly important. The detection method of transparency is: take a finished bag and observe it through an indirect indoor light source. If there are "specks", "rings", "haze", etc. in the blank area, it indicates that the transparency is poor; otherwise, it indicates that the transparency is good.

There are many reasons for poor transparency. For example, during compounding, due to the yellowish or reddish color of the compounding adhesive itself, transferring to the composite bag will cause corresponding color deviation, affecting its transparency; if the transparency of the material itself is poor and there is "haze", it will also affect its transparency. Therefore, the quality should be strictly controlled when the material enters the warehouse, and unqualified raw materials should not be allowed to enter the warehouse. In addition, the transparency of different composite raw materials is also different, such as the transparency of cast CPP is much higher than that of blown co-extruded CPP.