With the development of the market, there are more and more diversified requirements for consumption. The stand-up bag has attracted the attention of many people with its unique shape and convenient features. As the scale of stand-up pouches expands, common quality problems are constantly being raised, mainly including leakage, uneven bag shape, asymmetric bottom seal, and size errors. Today yltpackaging brings you a solution. 1. Bag leakage The main reason for the leakage of the stand-up pouch lies in the selection of composite materials and the strength of heat seal. 1. Selection of materials The selection of materials has a great influence on the quality of stand-up pouches. Appropriate materials can ensure the heat sealing strength of the stand-up pouch and the peel strength between the material layers, ensuring that the stand-up pouch is not easily damaged. Therefore, the self-supporting pouch generally requires that the surface tension of the composite surface of the film must be greater than 38dyn/cm; the low-temperature heat-sealing performance of the inner heat-sealing film is better, and the surface tension of the heat cover must be less than 34dyn/cm; in addition, the ink with good connection performance should be selected , High solid content low viscosity adhesive, high purity organic solvent. 2. Heat seal strength The low heat seal strength is also the reason for the leakage of the stand-up pouch. The heat seal strength is low, and the heat seal may be separated under the action of the external environment, resulting in leakage. Therefore, the heat-sealing temperature and heat-sealing pressure should be set according to the characteristics of the stand-up pouch material. After the heat sealing is completed, a leak test is required. The simplest and most practical method is to fill the bag with a certain amount of air, heat seal the mouth of the bag, put it into a basin filled with water, and squeeze different parts of the bag with your hands. , if no air bubbles escape, it means that the sealing and airtightness of the bag is good. In addition, the four-layer seal at the bottom of the stand-up pouch is the most critical part. The heat-sealing temperature, heat-sealing pressure and heat-sealing time can only be determined after full test verification. 2. Unevenness of bag shape Flatness is one of the indicators to measure the appearance quality of packaging bags. In addition to material factors, the flatness of stand-up pouches is also related to factors such as heat-sealing temperature, heat-sealing pressure, heat-sealing time and cooling effect. If the heat-sealing temperature is too high or the heat-sealing pressure is too high or the heat-sealing time is too long, the composite film will shrink and deform. Insufficient cooling will result in insufficient shaping after heat sealing, unable to eliminate internal stress, and cause wrinkles in the bag, so the process parameters should be adjusted and the cooling water circulation system should work properly. 3. Poor symmetry Poor symmetry will not only affect the aesthetics of the bag, but also affect the heat sealing performance and stability. The main reasons for the poor symmetry of the stand-up pouch include uneven thickness of the composite film, ruffles, too small tension of the double floating rollers, improper control of the tension of the bottom material, and some rollers are not rotating smoothly. Therefore, if you want to avoid it, you have to take targeted solutions. It can be corrected by adjusting the tension of the double floating rollers, checking and adjusting the relevant guide rollers (such as compensation rollers, deflection adjustment rollers, etc.), appropriately reducing the discharge tension, and increasing the waiting time during heat sealing. In addition, the asymmetry of the bag shape will also be related to factors such as photoelectric tracking, feeding, cursor design, rubber roller balance, stepper motor or servo motor synchronization. This problem should be solved according to the specific operation of different products and different bag making equipment. 4. Dimensional error Stand-up pouch size error is one of the common problems in production. Dimensional errors can affect customer satisfaction and even lead to product returns. The reasons for the size error mainly include the excessive error of the bag length fixing system of the bag making mechanism, inaccurate tracking of the electric eye, and operational factors, such as improper tension control, insufficient pressure setting of the film-moving rubber roller pressure cylinder, etc. To avoid size errors, it is necessary to strictly control the operation, adjust the bag making speed and the working status of the electric eye. Reset the fixed-length system, adjust the pressure of the film-moving rubber roller, the cylinder pressure and the tension of each part.