Material Drying
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Non-Moisture Causes of PC Silver Streaks
Fenómeno do problema
Silver streaks still appear on the products after sufficient drying, and adjusting the drying parameters brings no improvement
Análise das causas
Besides moisture, PC silver streaks may also be caused by uneven plasticization due to too low melt temperature, material tearing caused by excessive shear rate, or gasification of mold release agent and foreign contamination; the mechanisms are different
Solução
①First verify the moisture content to exclude moisture factors; ②increase the barrel and nozzle temperatures; ③reduce the injection speed; ④stop using mold release agent and clean the screw to exclude contamination; after adjustment, take samples continuously to verify the effect, and resume mass production only after confirming stability
Conclusão principal
Silver streaks are the most common PC defect but have multiple causes; exclude them item by item in the order of moisture, temperature, shear and contamination to avoid repeated ineffective drying; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
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