The difference between four-side sealing bags, three-side sealing bags and back-sealing bags

 Four-side sealing bags have all experienced heat-sealing packaging. The current common granular packaging form has mature technology and simple process. The equipment has high operating stability, beautiful appearance, and good product sealing. So let’s learn about the differences between four-side sealing bags, three-side sealing bags, and back-sealing bags!

   Four-side sealing bags generally use a whole film divided into two halves for relative packaging. It is a method of cutting a single bag after the whole hot rod bag. During production, only one side needs to be aligned to achieve a good packaging effect. It is therefore important that packaging/equipment adaptability and packaging operation stability are very high. Because four-sided envelopes are generally slower than packaging machines, the general model is to combine multiple four-sided sealed bags with one packaging machine. At the same time, since each edge passes through the hot rod evenly, the product after being bagged has better sealing performance.

   The disadvantage of the four-side sealing bag is that it has insufficient adaptability to volume packaging. The entire film is made into pockets first and then cut. Therefore, the composite film is relatively flat when making the bag. The back pocket of the bag is flat and the volume is difficult to load. The space in the four-side sealing bag is utilized. The rate is relatively low.

   One side of the three-side sealing bag is directly folded into a composite film, and the other three sides are heat-sealed. In fact, three-side sealing bags can be regarded as a supplement to four-side sealing bags. Compared with four-side sealing bags, the advantage is that after becoming a bag, it can be expanded into a three-dimensional bag shape first. It has high space utilization and is suitable for large-scale packaging needs. It is often used for packaging products such as cold granules.

   The disadvantages of three-side sealing bags are also obvious. First of all, the asymmetric impact of the bag type caused by the three-side sealing bag is aesthetic. Of course, everyone has different opinions on aesthetic issues. Not much discussed here. Second, the packaging speed is slow. The common packaging form of three-side sealing bags is single-row packaging (this is why the three-side sealing bags are suitable for batch packaging. Because only thermal insulation can ignore the smoothness requirements of the composite film.

   The roll film is first divided into heat, each composite film is longitudinally sealed towards one side, and then the package is sealed transversely. Bai Fengbai's advantages are obvious. First of all, the appearance is very beautiful. The hidden back-seal bag and bag-like features used in the back-seal bag clearly determine the appearance characteristics. The exquisite bag-shaped tube has obvious advantages compared with the same type of four-side-seal bag products. Second, the back-sealed bag combines several rows of four-side sealed bags, combining the advantages of packaging speed and high space utilization of three-sided sealed bags. Relatively speaking, four-side sealing bags can reduce the use of packaging materials by about 40% without affecting production speed, and the packaging cost advantage is very obvious.

   The disadvantages of back-sealed bags are also obvious. First of all, according to the method of splitting the composite film first and then making the bags in each row, the back-sealing bag has poor adaptability to packaging materials/packaging equipment, and the bag shape of the back-sealing bag makes it difficult to organize the subsequent boxes. Therefore, the initial equipment for the back-sealing bag The investment is large and the operation and maintenance costs are high. Second, the horizontal sealing position of the back-sealed bag is that the bell edge is sealed together with the composite film, so heat sealing is difficult. The bag sealing performance is lower than that of the four-sided bag, and the risk of bag sealing failure is also significantly higher than that of the four-sided bag. In short, four-side sealing bags, three-side sealing bags, and back-sealing bags all have obvious characteristics and unique scope of application. Some characteristics are the advantages of the packaging form, but they are also the source of defects. How to choose the appropriate packaging form depends on the company's products and packaging form. For example, for high-volume products, the form of four-side sealing bags is difficult to withstand. Three-side sealing bags and back-sealing bags can better solve this problem.

   The above introduction is the difference between four-side sealing bags, three-side sealing bags, and back-sealing bags. If you need to know more, you can contact us at any time!

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