Extrusion & Post
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Wrinkles appearing in polyolefin plastomer blown films
Problem Phenomenon
The film shows longitudinal wrinkles during hauling, affecting the flatness of the film and subsequent processing.
The wrinkles are more obvious after winding and, in severe cases, cause the film to be scrapped.
Cause Analysis
（1）The film thickness is uneven, and the thin parts shrink first, producing wrinkles
（2）The hauling roller pressure is uneven
（3）The angle of the herringbone plate is improper or the included angle is asymmetric
（4）The cooling line height is unstable
（5）Uneven cooling of various parts of the film causes different shrinkage
Solution
（1）Adjust the die gap and air ring to ensure uniform film thickness
（2）Adjust the hauling roller pressure to ensure uniform clamping
（3）Adjust the herringbone plate angle to be symmetric, generally with an included angle of 30-45°
（4）Stabilize the cooling line height, with fluctuation not exceeding ±50mm
（5）Check the uniformity of air ring cooling, and replace with a high-efficiency air ring when necessary
Key Takeaway
Wrinkles are caused by uneven thickness or unbalanced hauling, and need to be solved from thickness control, hauling, and herringbone plate adjustment.
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