Material Drying
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PET preform white haze
Problem Phenomenon
White haze appears on the preform; the white haze expands after bottle blowing, and the transparent bottle is scrapped
Cause Analysis
Insufficient raw '2079851475616104451 is the primary cause of preform white haze; too low screw heating temperature and poor plasticization also produce white haze; white haze is amplified and more obvious in stretch '2079851475616104457; during on-site troubleshooting, verify item by item according to this mechanism, and avoid blindly adjusting the machine based only on experience
Solution
① Stop the machine and fully re-dry the raw material; ② appropriately increase the screw heating temperature; ③ reject white-haze preforms and do not let them flow into the blowing process; after adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability
Key Takeaway
Preform white haze is a clear signal of insufficient drying; preform inspection interception plus drying rectification prevents defects from flowing into blowing and being amplified; after confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence
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