Injection Molding
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MP '2079851475616104452 sink marks
Problem Phenomenon
MP injection molded products have surface depressions 0.2-0.5mm in thick-wall regions, sink marks
Cause Analysis
holding pressure insufficient or holding time short; gate freezes prematurely, holding cannot be transmitted; large wall thickness difference, thick wall cannot be fed after the thin wall freezes
Solution
1) raise holding pressure 70-90MPa; 2) extend holding to gate freeze +2s; 3) product design to reduce wall thickness difference with gradual transition; 4) add supplementary gates in thick-wall regions
Key Takeaway
sink marks are caused by insufficient holding and wall thickness difference; high-pressure holding and multiple gates are the core countermeasures
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