Injection Molding
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PA6 '2079851475616104452 flash
Problem Phenomenon
Thin flake flash at the parting line and ejector pins, needs trimming after demolding, more obvious in individual cavities of multi-cavity molds.
Cause Analysis
PA6 melt viscosity is low and easily seeps into fitting gaps under high pressure; high injection pressure, insufficient clamping, and mold wear all induce it; low viscosity is the material root cause of PA6 flash.
Solution
①Reduce injection and holding pressure, lowering by 5%~10% each time while observing; ②calculate whether the clamping force is sufficient based on the projected area of the product; ③repair the fitting gaps of the parting line and ejector pins; ④appropriately lower the melt temperature to increase melt viscosity; ⑤troubleshoot filling imbalance in multi-cavity molds.
Key Takeaway
PA6 flash='low viscosity meets pressure and gaps': reducing pressure is the first choice, repairing fits is fundamental; nylon melt is thin and extremely sensitive to both pressure and gaps, so process and mold must be addressed on both fronts.
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