Molds & Tooling
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POM product black specks
Problem Phenomenon
Black specks appear in white or light-colored POM products at non-fixed positions; black specks gradually decrease after purging but still occur occasionally between batches.
Cause Analysis
Burnt material carbide formed on the barrel wall over a long time falls off and mixes into the resin; degradation of stagnant material in hot runner dead corners is also a source of black specks, gradually released as production time passes.; during on-site troubleshooting, verify item by item according to this mechanism, and avoid blindly adjusting the machine based only on experience
Solution
①Thoroughly clean the barrel before '2079851475616104452; ②shorten material residence time; ③regularly disassemble and inspect the screw and nozzle; ④establish black speck frequency records to monitor trends.; after adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability
Key Takeaway
Black specks originate from the slow release of carbide inside the equipment; regular preventive purging is more economical than after-the-fact handling, and black speck records can guide purge cycle setting.; after confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence
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