Extrusion & Post
3 Aufrufe
Uneven wall thickness of linear low density polyethylene extruded pipes (Variant: strengthened measures)
Problembeschreibung
Pipe wall thickness is uneven in the circumferential direction, showing eccentric wall phenomenon.
Uneven wall thickness affects pipe pressure resistance; the thin-wall side ruptures first under pressure, seriously affecting pipe use safety.
In particular, additional attention is needed on the original basis; this problem is more prominent and requires key attention.
Ursachenanalyse
(1) Die and mandrel not concentric, uneven gap
(2) Uneven melt temperature; large temperature difference around the die circumference
(3) Uneven extruder output, melt pressure fluctuation
(4) Unstable haul-off speed or haul-off center not concentric with the die
(5) Pipe sizing sleeve worn or improperly installed
(6) On the original basis, additional attention is needed as process parameter fluctuations or equipment status changes have aggravated this problem
Lösung
(1) Adjust the concentricity of die and mandrel; circumferential gap error not exceeding ±0.05mm
(2) Check die heater band distribution, ensure circumferential temperature difference not exceeding ±3°C (190-250°C range)
(3) Check extruder plasticizing stability, ensure uniform output
(4) Align the haul-off device centerline with the die center
(5) Check the sizing sleeve; replace if severely worn, ensure concentric installation
(6) And strengthen process monitoring; on the original basis, additional attention is needed, with special attention to parameter stability
Wichtigste Erkenntnis
Uneven wall thickness is caused by uneven die gap or uneven temperature; it needs to be solved from mold accuracy and temperature uniformity.
Targeted preventive measures need to be taken in different production scenarios.
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