The film is too sticky and the opening is poor. Causes: 1 The resin material is not the correct type. It is not a blown film grade low density polyethylene resin particle, and the content of the opening agent or the opening agent is not low. 2 The temperature of the molten resin is too high, and the fluidity is low. 3 is too large; 3 inflation ratio is too large, resulting in poor opening of the film; 4 cooling rate is too slow, film cooling is insufficient, under the action of traction roller pressure, mutual bonding; 5 traction speed is too fast.
Solution: 1 replace the resin raw materials, or add a certain amount of opening agent to the hopper; 2 appropriately reduce the extrusion temperature and the temperature of the resin; 3 appropriately reduce the inflation ratio; 4 increase the air volume, improve the cooling effect, and accelerate the film cooling Speed; 5 properly reduce the traction speed. 2. Reasons for poor transparency of the film: 1 The extrusion temperature is low, the resin is poorly plasticized, resulting in poor transparency of the film after blowing; 2 The blow ratio is too small; 3 The cooling effect is not good, thus affecting the transparency of the film; The moisture content in the resin raw material is too large; 5 the pulling speed is too fast, and the film cooling is insufficient.
Solution: 1 Appropriately increase the extrusion temperature so that the resin can be plasticized uniformly; 2 Increase the inflation ratio appropriately; 3 Increase the air volume and improve the cooling effect; Dry the raw materials; 5 Reduce the traction speed appropriately.
3. The wrinkles of the film are caused by the failure: 1 the thickness of the film is not uniform; 2 the cooling effect is not enough; 3 the inflation ratio is too large, causing the bubble to be unstable, swinging back and forth, easy to wrinkle; 4 the angle of the collet Large, the bubble is flattened in a short distance, so the film is also prone to wrinkles; 5 the pressure on both sides of the traction roller is inconsistent, one side is high and the other side is low; 6 the axis between the guide rolls is not parallel, affecting the stability of the film and peace Extensibility, resulting in wrinkles. Solution: 1 adjust the thickness of the film to ensure uniform thickness; 2 improve the cooling effect, ensure that the film can be fully cooled; 3 properly reduce the inflation ratio; 4 appropriately reduce the angle of the herringbone splint; 5 adjust the pressure of the traction roller, Ensure that the film is evenly stressed; 6 Check the axes of the guide shafts and make them parallel to each other. 4, the film has foggy water ripple failure reasons: 1 extrusion temperature is low, resin plasticization is poor; 2 resin is damp, moisture content is too high. Solution: 1 Adjust the temperature setting of the extruder and increase the extrusion temperature appropriately. 2 Drying the resin raw material generally requires that the water content of the resin should not exceed 0.3%. 5. Uneven film thickness failure Cause: 1 The uniformity of die gap directly affects the uniformity of film thickness. If the die gap is not uniform, some parts have larger gaps, and some parts have smaller gaps, resulting in extrusion volume. There are many or less, therefore, the thickness of the formed film is also inconsistent, some parts are thin, some parts are thick; 2 the temperature distribution of the die is uneven, high and low, so that the film after blow molding is thin and uneven; 3 The air supply volume around the cooling air ring is inconsistent, resulting in uneven cooling effect, resulting in uneven thickness of the film; 4 inflation ratio and traction ratio are not suitable, making the bubble thickness difficult to control; 5 traction speed is not constant , constantly changing, which of course affects the thickness of the film. Solution: 1 Adjust the die gap of the machine head to ensure uniformity everywhere; 2 Adjust the temperature of the die head to make the temperature of the die part uniform; 3 Adjust the cooling device to ensure the air outlet volume is even; 4 Adjust the inflation Ratio and traction ratio; 5 Check the mechanical transmission to keep the traction speed constant. 6. The thickness of the film is thicker. Causes: 1 The die gap and the extrusion amount are too large, so the film thickness is thick; 2 The cooling air ring has too much air volume, and the film cooling is too fast; 3 The pulling speed is too slow. Solution: 1 Adjust the gap of the die; 2 Reduce the air volume of the air ring properly, so that the film is further inflated, so that the thickness is thinner; 3 Appropriately increase the traction speed 7. The thickness of the film is thin. Cause: 1 die The gap is too small, the resistance is too large, so the thickness of the film is thin; 2 the air volume of the cooling air ring is too small, the film cooling is too slow; 3 the pulling speed is too fast, the film is stretched excessively, so that the thickness is thinned. Solution: 1 Adjust the gap of the die; 2 Increase the air volume of the air ring to accelerate the cooling of the film; 3 Reduce the traction speed appropriately. . The heat sealing property of the film is poor. Causes: 1 The dew point is too low, the polymer molecules are oriented, so that the performance of the film is close to the oriented film, resulting in a decrease in heat sealing performance; 2 the inflation ratio and the traction ratio are not appropriate (too large), the film The stretching orientation occurs, thereby affecting the heat sealing properties of the film. Solution: 1 Adjust the amount of wind in the wind ring, make the dew point higher, and inflate and pull as much as possible under the melting point of plastic to reduce the molecular stretching orientation caused by inflation and traction; 2 inflation ratio and The traction ratio should be slightly smaller. If the inflation ratio is too large and the traction speed is too fast, the transverse and longitudinal stretching of the film is excessive, then the performance of the film tends to be biaxially stretched, and the heat sealability of the film will be Getting worse. 9. The longitudinal tensile strength of the film is poor. Causes: 1 The temperature of the molten resin is too high, which will cause the longitudinal tensile strength of the film to decrease. 2 The pulling speed is slow, and the longitudinal orientation of the film is insufficient, so that the tensile strength in the longitudinal direction is deteriorated; 3 The inflation ratio is too large, and the traction ratio is not matched, so that the transverse orientation and tensile strength of the film are improved, and the tensile strength in the longitudinal direction is deteriorated; 4 The cooling rate of the film is too fast. Solution: 1 appropriately reduce the temperature of the molten resin; 2 appropriately increase the traction speed; 3 adjust the inflation ratio to match the traction ratio; 4 appropriately reduce the cooling rate. 10. The transverse tensile strength of the film is poor. Causes: 1 The traction speed is too fast, and the difference between the inflation ratio is too large, so that the longitudinal direction is fibrillated, and the lateral strength is deteriorated; 2 The cooling rate of the cooling air ring is too slow. Solution: 1 Reduce the traction speed properly and match it with the inflation ratio; 2 Increase the air circulation volume to make the inflation film cool rapidly and avoid being stretched and oriented in the high elastic state. 11. Bubble instability failure reasons: 1 Extrusion temperature is too high, the fluidity of the molten resin is too large, the viscosity is too small, and it is easy to produce fluctuations; 2 The extrusion temperature is too low, the discharge amount is small; 3 The air volume of the cooling air ring Unstable, the bubble cooling is uneven; 4 is affected by the interference and influence of the external strong airflow. Solution: 1 adjust the extrusion temperature; 2 adjust the extrusion temperature; 3 check the cooling air ring to ensure uniform air supply around the four; 4 to prevent and reduce the interference of the external airflow.
12, the film surface is rough, unevenness Causes of failure: 1 extrusion temperature is too low, resin plasticization is poor; 2 extrusion speed is too fast. Solution: 1 Adjust the temperature setting of the extrusion, and increase the extrusion temperature appropriately to ensure that the resin is plasticized well; 2 Reduce the extrusion speed appropriately. 13. The film has odor failure causes: 1 The resin material itself has an odor; 2 The extrusion temperature of the molten resin is too high, causing the resin to decompose, thereby producing an odor; 3 the bubble cooling is insufficient, and the hot air in the bubble is not eliminated. Solution: 1 replace the resin raw material; 2 adjust the extrusion temperature; 3 increase the cooling efficiency of the cooling air ring, so that the bubble is fully cooled.
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