Extrusion & Post
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Uneven thickness of polyolefin plastomer blown films (Variant: Enhanced Measures)
Problem Phenomenon
The film thickness fluctuates greatly in the circumferential or longitudinal direction, and the thickness deviation exceeds ±10%.
Uneven thickness affects the mechanical properties and service performance of the film, and may cause deviation or film breakage on automatic packaging machines.
In particular, additional attention is needed on the original basis; this problem is more prominent and requires focused attention.
Cause Analysis
（1）The die gap is uneven
（2）The temperature in the circumferential direction of the die is uneven
（3）The air ring cooling is uneven
（4）The extrusion output fluctuates
（5）The hauling speed is unstable
（6）On the original basis, additional attention is needed: fluctuations in process parameters or changes in equipment status have aggravated this problem
Solution
（1）Adjust the die gap, with the circumferential error not exceeding ±0.01mm
（2）Check the die heating ring to ensure the circumferential temperature difference does not exceed ±3°C (180-230°C range)
（3）Check the air ring to ensure uniform air output, and clean the air ring regularly
（4）Stabilize the extruder screw speed and temperature
（5）Stabilize the hauling speed, using a high-precision hauling control system
（6）And strengthen process monitoring; on the original basis, additional attention is needed to pay special attention to parameter stability
Key Takeaway
Uneven film thickness is caused by uneven die gap, temperature, or cooling, and needs to be solved from mold precision and process stability.
Targeted preventive measures need to be taken in different production scenarios.
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