Material Drying
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Bubbles in cross-linked polyethylene XLPE cable insulation layer (Variant: strengthened measures)
Problem Phenomenon
Bubbles or pinholes appear in the XLPE cable insulation layer, affecting insulation performance and pressure resistance.
Bubbles may develop into electrical trees during cable use, causing breakdown.
Especially on the original basis, additional attention is needed, and this problem is more prominent and requires key attention.
Cause Analysis
(1) High material moisture content, water vaporizes at high temperature
(2) Small molecular gas produced by peroxide decomposition not discharged in time
(3) Poor extrusion plasticization causes gas entrainment
(4) Too fast cooling after crosslinking prevents gas from escaping
(5) Unreasonable screw venting section design
(6) On the original basis, additional attention is needed: process parameter fluctuations or equipment state changes aggravate this problem
Solution
(1) Fully dry raw materials, control moisture content below 0.03%
(2) Improve extrusion venting section efficiency, add venting channels
(3) Optimize screw design to ensure full plasticization and venting
(4) Appropriately extend high-temperature holding time after crosslinking to vent gas
(5) Control cooling rate, should not be too fast
(6) And strengthen process monitoring; on the original basis, additional attention is needed, paying special attention to parameter stability
Key Takeaway
Bubbles in the cable insulation layer are caused by moisture and volatile gases, and need to be solved from raw '2079851475616104451 and the venting system.
Targeted preventive measures need to be taken in different production scenarios.
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