Injection Molding
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LDPE '2079851475616104452 Weld Line
Problem Phenomenon
Weld lines are obvious on multi-gate products, and strength at the weld line of thin-walled parts is insufficient
Cause Analysis
LDPE has good fluidity but the melt fronts join poorly after cooling down; weld lines are more obvious at low mold temperature; parts with high strength requirements should avoid weld lines; when troubleshooting on site, verify item by item according to this mechanism, and avoid blindly adjusting the machine based only on experience
Solution
① Raise mold temperature to improve joining quality; ② optimize gate position for weld line position; ③ single-gate design when necessary; after adjustment, take continuous samples to verify the effect, and resume mass production only after confirming stability
Key Takeaway
LDPE weld line treatment mainly relies on temperature and position; high-flow materials also need a gate strategy; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
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