Four side sealing bag
That is, the four sides of the bag are all sealed in a heat-sealed form, and the most common form of granule packaging is mature in technology and simple in process. The equipment has high running stability, relatively beautiful appearance and good product sealing.
The four-side sealing bag is usually divided into two halves and then relatively packaged by using a whole film. It is a method of cutting a single bag after the whole heat-sealing bag, and only needs to control one edge to be aligned to obtain a better packaging effect. Therefore, it has extremely high packaging/equipment adaptability and packaging operation stability (this is very important, because the speed of the four-side bag sealing machine is usually slower than that of the cartoning machine, the common mode is multiple four-side bag sealing machine with one box Machine use, the requirements for equipment operation stability are higher). At the same time, since each side is uniformly heat-sealed, the product after bagging has better sealing performance.
The shortcoming of the four-side sealing bag is that the packaging adaptability to the bulk material is insufficient. Because the whole film is cut after the bag is first formed, the composite film is required to be relatively flat when the bag is formed, and the bag body is flat after the bag is formed, and it is difficult to load the bulk material. The space utilization rate inside the bag is relatively low.
Back sealing bag (also known as Stick packaging)
That is, the film is first cut into a series, and each column of composite film is rolled into a vertical seal, and then the longitudinal seal is pressed to one side, and then the method of transversely sealing the bag is first invented by a Japanese company. The advantages of the back sealing bag are very obvious. Firstly, the shape is very beautiful. The hidden vertical sealing edge and bag type characteristics of the back sealing bag determine the distinctive appearance and the bag shape is exquisite and beautiful. Compared with the same type of four-side sealing products, Significant differentiation advantages. Secondly, the back sealing bag combines the advantages of high packing speed of four-side sealing bag and high space rate of three-side sealing bag. Compared with the four-side sealing bag, it can reduce the dosage of packaging materials by 40% without affecting the production speed. With a very obvious packaging cost advantage.
The shortcomings of the back sealing bag are also very clear. Firstly, the method of separately forming the bag after slitting the composite film determines that the back sealing bag has the worst adaptability to the packaging material/packaging equipment, and the bag shape of the back sealing bag determines its Subsequent finishing of the boxing is the most difficult, so the initial equipment investment of the back sealing bag is huge, and the operation and maintenance cost is high (it is also because the entry threshold is high, which highlights the difference in the appearance of the back sealing bag). Secondly, the horizontal sealing position of the back sealing bag is to seal the longitudinal sealing edge together with the composite film bag, so the heat sealing is difficult, the bag sealing property is lower than the four-side sealing bag form, and the risk of bag sealing failure is also significantly higher than the four sides. Seal the bag.
In short, whether it is a four-side bag or a back-sealing bag (Stick packaging), it has its distinctive features and unique scope of application, and some features are both the advantages of its packaging form and the source of its defects. How to choose the right packaging form should be determined according to the company's product and packaging form. For example, for high-volume products, the four-side sealing form is difficult to handle, and the three-side sealing and back sealing bags can better solve this problem.
