Injection Molding
4 views
LLDPE '2079851475616104452 sink mark
Problem Phenomenon
Sink marks in thick-wall areas of LLDPE injection molded parts are lighter than LDPE, but holding pressure control is still needed
Cause Analysis
LLDPE shrinkage 1.5-3% is lower than LDPE, with smaller sink mark tendency; but shrinkage compensation needs in thick-wall areas still exist; holding pressure and time are optimized by wall thickness
Solution
①Set holding pressure at 60-80% of injection pressure; ②thin the structure in thick-wall areas; ③place the gate near thick-wall areas; after adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability
Key Takeaway
LLDPE's low shrinkage reduces sink marks; but holding pressure management for thick-wall parts remains a necessary step; after confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence
Was this helpful?
0 people found this helpful
Thank you for your feedback!