Molds & Tooling
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HDPE film PPA eliminating die lip buildup
Problem Phenomenon
Serious die lip buildup requires frequent shutdown for cleaning; the buildup disappears after adding a fluorine-containing processing aid.
Cause Analysis
Melt wall adsorption and stress concentration at the die lip make degraded material gradually accumulate; PPA forms a lubricating layer on the die wall, preventing the buildup from adhering.; when troubleshooting on site, verify item by item according to this mechanism, and avoid blindly adjusting the machine based only on experience
Solution
①Add 300ppm-level PPA processing aid; ②establish a record of the onset time; ③coordinate with die lip temperature optimization; ④regularly evaluate the additive effect.; after adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability
Key Takeaway
PPA is a highly efficient means of eliminating die lip buildup; it takes effect at a low addition amount, but attention should be paid to uniform dispersion and onset time.; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
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