According to the material, size and other aspects of the different, we have a variety of bag - making forms.Our bag-making methods are mainly as follows. 1.Pillow bag.The bag is sealed at both ends and at one end from the middle.This kind of packing comes in many forms.Standard Lap Seal(left over right);Reverse Lap Seal(right over left);Standard Fin Seal(left over right on center);Reverse Fin Seal(left over left on center);Offset Fin Seal Standard(left over right off center);Offset Fin Seal Reverse(right over left off center);Pinch Seal.As shown in the figure below.Compared with other packaging forms, the bag has no sealing side on both sides of the bag body, so the pattern on the front of the package is complete and more beautiful.At the same time, the pattern of the bag body can be designed as a whole in the layout design to maintain the continuity of the picture.And since the sealing is on the back, both sides of the bag can withstand greater pressure, reducing the possibility of packaging damage.And the same size of the packaging bag with the form of back sealing the total length of the smallest, which also from a certain sense to reduce the probability of sealing cracking. 2.Gusseted bag.Gusseted bag is also a very common way to make bags.To make this kind of packing machine, it is necessary to have an Angle insertion device. 3.punching bag.These bags usually have holes punched in the top of the package.This is to make it easy to put or take on the shelves. 4.Three sides sealing and four side sealing.Three-sided seal and four-sided seal means that there are three or four sides that are machine sealed 5.Doy bag.This bag is equipped with a zipper, which can be removed at any time.It is easy to take and take.It is especially suitable for materials that can not be used up at one time. Secondly, the selection and use of qualified plastic food packaging bags should pay attention to the following points: 1.Food should have inspection certificate on the outside of plastic bag. 2.Plastic packaging bags for food are odorless and odorless when they leave the factory.Plastic packaging bags with special smell cannot be used for food packaging. 3.Try not to add coating, coating material.