1. The material of the bag:
Aluminum foil bags need to be odor free. Bags with peculiar smell generally make people feel that they do not meet hygienic standards, and may also affect the normal use of the bag. If there is no peculiar smell, you need to check the transparency of the bag, whether the clarity is uniform, whether there is a sense of impurities, etc.
2. Printing quality:
See if there is an obvious third color at the splicing of the two colors. The higher the level of fidelity of the physical map, the better, and see if there are any phenomena such as drawing, fogging, blocking, and missing printing.
3. The uniformity of the appearance:
First observe the stiffness of the bag. Generally, the higher the flatness, the better, except for the needs of different materials. For example, a bag made of nylon and high-pressure film will have a wave shape at the heat-sealed part of the bag; it is also necessary to observe whether the trimming of the bag is neat, the more neat the better.
4. The firmness of the bag. The firmness of the bag is mainly divided into two types: fit firmness and hot air firmness. Bags vary in strength due to the selection of materials. The main way to distinguish is to tear the edge of the bag by hand. If it is difficult to tear, it means that the heat seal is firm. Otherwise it is not good.