Extrusion & Post
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Uneven thickness of linear low-density polyethylene blown film (variant: strengthened measures)
Problembeschreibung
Film thickness fluctuates greatly in the circumferential or longitudinal direction, with thickness deviation exceeding ±10%.
Uneven thickness affects the mechanical properties and service performance of the film, and may cause deviation or film breakage on automatic packaging machines.
Especially, additional attention is needed on top of the original basis; this problem is more prominent and requires focused attention.
Ursachenanalyse
(1) Die gap is uneven
(2) Die temperature is uneven in the circumferential direction
(3) Air ring cooling is uneven
(4) Extrusion output fluctuates
(5) Haul-off speed is unstable
(6) On top of the original basis, additional attention is needed as process parameter fluctuations or equipment condition changes aggravate this problem
Lösung
(1) Adjust the die gap, with circumferential error not exceeding ±0.01mm
(2) Check die heating bands to ensure circumferential temperature difference does not exceed ±3°C (190-250°C range)
(3) Check the air ring to ensure uniform air output, and clean the air ring regularly
(4) Stabilize extruder screw speed and temperature
(5) Stabilize haul-off speed and use a high-precision haul-off control system
(6) And strengthen process monitoring; on top of the original basis, additional attention is needed to pay special attention to parameter stability
Wichtigste Erkenntnis
Uneven film thickness is caused by uneven die gap, temperature or cooling and needs to be solved from mold precision and process stability.
In different production scenarios, targeted preventive measures need to be taken.
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