How to inspect the appearance of vacuum bag?

　　Visual inspection of appearance includes inspection of flatness and transparency of vacuum bag. It is mainly used to detect whether there are obvious scratches and pinholes on the surface, and whether there is pollution at the seal. The appearance inspection methods are as follows:

　　1: Vacuum bag surface wiredrawing "inspection. Place the vacuum packaging bag in the center of your hand, aim at the 40w fluorescent lamp, and gently shake it. Through the reflected light on the surface of the composite bag, you can clearly find whether there are scratches or marks on the surface of the vacuum packaging bag, which is often called "bag surface wiredrawing" in the industry. The wire drawing phenomenon is mostly caused by the unclean traction guide roller of the bag making machine, so it must be ensured that the guide roller is clean. In addition, if the guide roller does not rotate, it will also cause drawing failure of the vacuum packaging bag.

　　2: Check the flatness of the vacuum bag. Place the vacuum bag on a flat table. If the surface is bent, warped outwards or arched inwards, the flatness is poor,

　　Otherwise, it indicates good flatness. The reasons for poor flatness are generally as follows: high bag making temperature has damaged the stress stiffness of the inner layer of the composite bag; Unreasonable structure composition; The material itself is uneven in thickness.

　　3: Check the transparency of the vacuum bag. Transparency is particularly important for some products because there is no pattern on a large area. The transparency test method is: take a finished bag and observe it through the indoor indirect light source. If there are "pockmarks", "rings", "fog" and other phenomena in the blank, it indicates poor transparency, otherwise it indicates good transparency.

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