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The film surface is rough and uneven.
Analysis:
1.Extrusion temperature is too low and the resin plasticizing is poor.
2.Extrusion speed is too fast.
Solution:
1. Adjust the extrusion temperature setting, and appropriately increase the extrusion temperature, to ensure good resin plasticization.
2. Reduce the extrusion speed appropriately.
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The differential transversal tensile strength of the film.
Analysis:
1. Traction speed is too fast, with the blowing expansion ratio difference is too big, make longitudinal fibrosis, transverse strength becomes worse.
2. The cooling rate of the cooling air ring is too slow.
Solution:
1. Reduce the traction speed appropriately to cooperate with the blowing ratio.
2. Increase the air volume, so that the swelling film quickly cooling, avoid being stretched in the high elastic state of higher temperature.
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Poor longitudinal tensile strength of the film.
Analysis:
1.The temperature of the molten resin is too high to reduce the longitudinal tensile strength of the film.
2.The traction speed is slow, and the longitudinal orientation of the film is not enough, so that the longitudinal tensile strength becomes worse.
3.The swelling ratio is too large, and the traction ratio does not match, so that the transverse orientation and tensile strength of the film is increased, and the longitudinal tensile strength will become worse.
Solution:
1. Reduce the temperature of the molten resin appropriately.
2. Increase the traction speed appropriately.
3. Adjust the blowing and expansion ratio to adapt it to the traction ratio.
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The thermal sealing properties of the films are poor.
Analysis:
1. The dew point is too low, the polymer molecules are oriented, so that the performance of the film is close to the directional film, resulting in the reduction of thermal sealing performance.
2. The blowing ratio and traction ratio are not appropriate (too large), and the film has a tensile orientation, which affects the thermal sealing performance of the film.
Solution:
1. Adjust the size of the air volume in the wind ring, so that the dew point is higher, as far as possible under the melting point of plastic, in order to reduce the tensile orientation of molecules caused by swelling and traction.
2. The blowing ratio and traction ratio should be appropriately smaller. If the blowing 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 will tend to be bidirectional stretching, and the thermal sealing of the film will become worse.
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The film has a mist-like water pattern.
Analysis:
1. The extrusion temperature is low, and the resin is poorly plasticized.
2. Resin is damp, and the moisture content is too high.
Solution:
1. Adjust the temperature setting of the extruder and raise the extrusion temperature appropriately.
2. When drying resin raw materials, the water content of resin should not exceed 0.3%.
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The film was wrinkled.
Analysis:
1.The film thickness is not uniform.
2.Swelling ratio is too large, resulting in the membrane bubble instability, left and right swing back and forth, easy to wrinkle.
3.The Angle of the human character splint is too large, and the film bubble is flattened in a short distance, so the film is also prone to wrinkle.
Solution:
1. Adjust the thickness of the film to ensure the uniform thickness.
2. Reduce the swelling ratio appropriately.
3. Reduce the Angle of the human character splint appropriately.
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Thin film transparency is poor.
Analysis:
1. The extrusion temperature is low, and the resin plasticization is poor, resulting in the poor transparency of the film after blowing molding.
2. The cooling effect is not good, which affects the transparency of the film.
3. The water content in the resin raw material is too large.
Solution:
1、Increase the extrusion temperature.
2、appropriately, so that the resin can be evenly plasticized.
2、Increase the air volume, improve the cooling effect.
3、Dry the raw materials.
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The film is too sticky and poor in opening.
Analysis:
1. Resin raw material model is not right, not blowing film grade low density polyethylene resin particles, which does not contain opening agent or opening agent content is low. The temperature of the molten resin is too high, and the fluidity is too large.
2. The temperature of the molten resin is too high, and the fluidity is too large.
3. The swelling ratio is too large, resulting in the poor opening of the film.
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 resin temperature.
3. Reduce the swelling ratio appropriately.
