Material Drying
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Defects caused by insufficient drying before processing of general-purpose polyethylene general-purpose polyethylene
Problem Phenomenon
Silver streaks, bubbles, and rough surface appear on the product surface, and the mechanical properties decrease.
The consequences of insufficient drying cover a variety of defect types and are a common problem in plastic processing.
Cause Analysis
（1）The raw material absorbs moisture (although general-purpose polyethylene has low water absorption, it still absorbs water after long-term exposure)
（2）The drying temperature is too low or the drying time is insufficient
（3）The drying equipment is faulty or the dehumidification capacity is insufficient
（4）The dried raw material is left in a humid environment for too long and absorbs moisture again
（5）The regrind is not dried or is insufficiently dried
Solution
（1）Use a dehumidifying dryer, drying temperature 60-80°C, time 2-4h
（2）Control the moisture content after drying below 0.02% (general-purpose polyethylene)
（3）Store the dried raw material sealed, cover the hopper, and expose to air for no more than 2h
（4）The regrind is dried in the same way as the new material
（5）Control the workshop environment humidity below 60%
Key Takeaway
Insufficient drying is a common root cause of processing defects, and a sound drying system and moisture content inspection system need to be established.
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