Material Drying
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Defects caused by insufficient drying before processing of linear low density polyethylene linear low density polyethylene (Variant: strengthened measures)
Problembeschreibung
Silver streaks, bubbles, and rough surface appear on the product surface, and mechanical properties decrease.
The consequences of insufficient drying cover multiple defect types and are a common problem in plastics processing.
In particular, additional attention is needed on the original basis; this problem is more prominent and requires key attention.
Ursachenanalyse
(1) Raw material absorbs moisture (although linear low density polyethylene has low water absorption, long-term exposure still absorbs water)
(2) Drying temperature too low or drying time insufficient
(3) Drying equipment failure or insufficient dehumidification capacity
(4) Dried raw material placed too long in a humid environment and re-absorbs moisture
(5) Regrind not dried or insufficiently dried
(6) On the original basis, additional attention is needed as process parameter fluctuations or equipment status changes have aggravated this problem
Lösung
(1) Use a dehumidifying dryer, drying temperature 60-80°C, time 2-4h
(2) Control moisture content after drying below 0.02% (linear low density polyethylene)
(3) Seal and store raw material after drying, cover the hopper, air exposure not exceeding 2h
(4) Dry regrind the same as virgin material
(5) Control workshop ambient humidity below 60%
(6) And strengthen process monitoring; on the original basis, additional attention is needed, with special attention to parameter stability
Wichtigste Erkenntnis
Insufficient drying is a common source of processing defects; a complete drying system and moisture content inspection system needs to be established.
Targeted preventive measures need to be taken in different production scenarios.
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