Injection Molding
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Nozzle Blockage in Block Copolymer Polypropylene '2079851475616104452
Fenómeno do problema
During injection, the melt cannot be normally injected from the nozzle or the injection amount decreases, and the injection pressure rises abnormally.
Nozzle blockage causes short shot or complete inability to produce, and is usually caused by cold material or impurities blocking the nozzle hole.
Análise das causas
（1）The nozzle temperature is low, and the melt cools and solidifies at the nozzle
（2）The mold sprue cold slug well is improperly designed, and cold material flows back into the nozzle
（3）The raw material contains impurities that block the nozzle hole
（4）The nozzle aperture is too small or the internal structure of the nozzle is unreasonable
（5）The nozzle and the mold sprue are poorly aligned, and eccentricity produces flash and material jamming
Solução
（1）Increase the nozzle temperature to a reasonable value within the 200-270°C range, 5-10°C lower than the front barrel temperature
（2）Check the mold sprue cold slug well to ensure the cold slug well size is sufficient
（3）Check the cleanliness of the raw material, and install a magnetic rack and filter screen on the hopper
（4）Select a nozzle with a suitable aperture; generally the nozzle aperture is 0.5-1mm smaller than the small end of the sprue
（5）Correct the alignment of the nozzle and the mold to ensure the coaxiality is within 0.05mm
Conclusão principal
Nozzle blockage is caused by cold material solidification or impurities, and needs to be solved from nozzle temperature, cold slug well design, and raw material cleanliness.
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