Injection Molding
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PP '2079851475616104452 Black Speck
Problem Phenomenon
Black specks and black streaks appear on light-colored PP parts.
Cause Analysis
Carbonized material shedding from barrel/hot runner dead spots; regrind contamination; degradation from long residence at high temperature.
Solution
①Purge and disassemble-clean dead spots; ②avoid high-temperature idling; ③control regrind cleanliness; ④thoroughly purge during material change.
Key Takeaway
Black speck control relies on normalized dead-spot cleaning.
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