1. Poor heat sealing strength Poor heat sealing strength means that the strength of the sealing position is lower than the standard requirements. 1. Causes 1. The adhesive in the composite film is not sufficiently hardened. 2. The heat sealing conditions are not suitable. 3. The interval between the heat sealing knife and the cooling knife is too long. 4. There is a problem with the inner seal film. 5. The heat-sealing resistance of the ink is poor, resulting in a decrease in the composite strength of the film at the heat-sealing part. 6. Dust, dusting and other substances are attached to the heat cover. 7. The composite strength is low or the composite strength of the heat seal is too much. 2. Treatment methods 1. Promote the hardening (curing, curing) of the adhesive through thermal insulation and aging, and improve the composite strength and heat resistance of the composite film. 2. Select the best heat-sealing conditions (temperature, time and pressure) according to the composition of the composite film, heat-sealing conditions, etc., or improve the heat-sealing method, and cool it immediately after heat-sealing. 3. Check the shelf life and storage conditions of the heat-sealing layer film. If the heat-sealing layer uses the old batch of film and the film that has been heat-sealed, special attention should be paid. 4. Increase the thickness of the heat seal layer film or check the degree of treatment of the heat seal. 5. Change the type and grade of the heat-sealing layer film, and use the inner-sealing layer film with anti-pollution heat-sealing properties. 6. Check whether the grade of the adhesive meets the requirements (the exudation of low molecular substances in the resin may sometimes affect the composition of the adhesive). 7. Improve the heat-sealing performance of the heat-sealing layer (substrate), control the content of the slip agent, and choose MLDPE film. 8. Control the monomer content of MDI in the composite adhesive. 9. Replace the ink (preferably use two-liquid ink). 10. Change the printing pattern of the packaging bag
so that the part printed with ink avoids the heat-sealing part, or change the heat-sealing method (pay special attention not to print metal ink on the seal). 2. Size error 1. Reasons for occurrence 1. The error of the bag length fixing system is too large. 2. Electric eye tracking is inaccurate. 3. The influence of the processing speed of plastic composite film bag making. 4. Operation reasons, such as improper tension control, insufficient pressure setting of the rubber roller pressure cylinder, etc. 2. Processing method 1. Adjust the fixed-length system. 2. Adjust the working condition of the electric eye. 3. Check for cursor printing problems or spacing problems, and adjust them. 4. Check whether the compression degree of the pressure film ruler and the friction coefficient of the composite film are appropriate. 5. The pre-adjusted film feeding length (when adjusting the white bag) and the actual bag-making standard should be as accurate as possible. 6. Decrease the bag-making speed, and adjust the bag-making speed slowly. 7. Adjust the rubber roller pressure, cylinder pressure and tension of each part. 3. There are spots on the cover and bubbles on the cover. There are spots on the cover. The bubbles refer to the uneven surface of the seal. 1. Causes 1. When heat sealing is performed on a hygroscopic material structure such as nylon film, the hygroscopic film absorbs moisture and generates air bubbles. 2. The heat sealing knife or the heat sealing silicone pad is not flat. 3. Insufficient heat sealing pressure. 4. Use one-component adhesives, such as neoprene adhesives, when heat sealing bags. Hot covers are prone to bumpy pits. 2. Treatment methods 1. Properly keep raw materials and semi-finished products to avoid moisture absorption. 2. Check or adjust the heat sealing knife and heat sealing silicone pad. 3. Replace the adhesive. Fourth, the upper and lower films are not inaccurate 1. Reasons for occurrence 1. The thickness of the composite film is uneven, and there are lotus leaf edges. 2. The tension of the double floating rollers is too small. 3. Some rollers roll unevenly. 2. Treatment method 1. Adjust the tension of the double floating rollers. 2. Check and adjust the relevant guide rollers (such as compensation rollers, deflection rollers, etc.).
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