Material Drying
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Defects caused by insufficient drying before heat-resistant polyethylene heat-resistant polyethylene processing
Problem Phenomenon
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.
Cause Analysis
(1) Raw material absorbs moisture (although heat-resistant 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 left in humid environment too long and re-absorbs moisture
(5) Regrind not dried or insufficiently dried
Solution
(1) Use a dehumidifying dryer, drying temperature 60-80°C, time 2-4h
(2) Control moisture content below 0.02% after drying (heat-resistant polyethylene)
(3) Seal and store raw materials after drying, cover the hopper, exposure to air not exceeding 2h
(4) Dry regrind the same as new material
(5) Control workshop ambient humidity below 60%
Key Takeaway
Insufficient drying is a common root cause of processing defects, and a complete drying system and moisture content detection system needs to be established.
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