Molding Process
2 views
PET melt pump pressure stabilization
Problem Phenomenon
Sinusoidal periodic fluctuations appear in sheet thickness, which the automatic thickness measurement system cannot completely eliminate
Cause Analysis
Slight fluctuations in melt pump speed appear as sinusoidal thickness bands; wear of the pump drive coupling introduces torsional oscillation; the closed-loop thickness measurement system can track it but cannot remove the upstream disturbance
Solution
① Check the melt pump drive coupling for wear; ② control pump speed fluctuation within 0.5%; ③ independently zone-heat the die bolts to control expansion; after adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability
Key Takeaway
The melt pump is the heart of PET sheet thickness stability; upstream fluctuations must be eliminated at the source, and downstream closed-loop is only a remedy; 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!