Material Drying
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POE '2079851475616104452 thick-wall bubbles
Problem Phenomenon
Dense bubbles of 0.1-0.5mm appear inside POE injection molded thick-wall products, concentrated in the center of the wall thickness
Cause Analysis
Holding pressure insufficient <40MPa or holding time short, thick-wall center not compacted; raw material contains moisture; injection speed too fast entraining air; poor mold venting
Solution
1) Increase holding pressure to 60-80MPa; 2) Extend holding time so the thick wall is fully compacted; 3) Fully dry the raw material, moisture <0.02%; 4) Add vent grooves or vent pins to the mold; 5) Progressive deceleration injection to avoid air entrainment
Key Takeaway
Thick-wall bubbles are caused by a combination of insufficient holding pressure, moisture and poor venting
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