Extrusion & Post
1 views
Unstable Bubble in LDPE Blown Film
Problem Phenomenon
The film bubble sways, shakes or even swings in a snake shape; film thickness deviation is large, and winding is uneven.
Cause Analysis
Insufficient melt strength makes the film bubble's anti-disturbance ability poor; too high melt temperature, low cooling efficiency and excessive extrusion output all aggravate instability; external airflow disturbance is also a cause.
Solution
①Control the melt temperature from being too high and reduce shear heat; ②improve cooling efficiency and adopt internal cooling and cold air; ③appropriately reduce the extrusion output; ④use a bubble stabilizer and isolate external airflow.
Key Takeaway
Bubble stability is the top priority of blown film production; temperature, cooling, extrusion output and bubble stabilizing device are tackled on all four fronts, with a stable frost line as the criterion for proper adjustment.; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
Was this helpful?
0 people found this helpful
Thank you for your feedback!