Processing Machinery
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ASA back pressure low value management
Problem Phenomenon
[Problem phenomenon] ASA back pressure too high shear heat accumulates, melt discolors and degrades
Cause Analysis
ASA screw back pressure recommended as low as 3.5bar (50psi) level; high back pressure shear heat generation makes actual melt temperature exceed setting, amorphous styrenics are sensitive to shear heat
Solution
Back pressure set at 3.5bar level low value; for insufficient plasticization, prioritize raising external heat; melt discoloration first check back pressure and speed; after adjustment, continuously sample to verify the effect, and resume mass production after confirming stability
Key Takeaway
ASA back pressure 3.5bar is the baseline, shear heat is an invisible overtemperature source; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence; include this case in the defect archive as a troubleshooting reference for subsequent similar problems
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