Material Drying
4 조회수
Product Defects Caused by Excessive Moisture Content of High-Density Polyethylene Raw Material
문제 현상
Silver streaks and bubbles appear on the product surface, voids are generated inside, and the mechanical properties decline.
Excessive moisture content of the raw material is the common root of many defects, and it is manifested in both product appearance and performance.
원인 분석
(1) The raw material absorbs moisture due to improper storage; although high-density polyethylene has low water absorption, it will still absorb water when exposed for a long time
(2) The drying equipment fails or the drying process is improper, and the dehumidification is insufficient
(3) The hopper is left open for too long, and the dried raw material absorbs moisture again
(4) The ambient humidity is high, and the raw material absorbs water during conveying
(5) The regrind is used directly without drying
해결 방법
(1) Use a dehumidifying dryer; the drying temperature of high-density polyethylene is 60-80°C, and the drying time is 2-4h
(2) Use the dried raw material in time; install an insulated cover on the hopper, and the residence in the hopper does not exceed 2h
(3) Control the workshop ambient humidity below 60%
(4) The regrind must be dried before use, with drying parameters consistent with the new material
(5) Regularly test the moisture content of the raw material and control it below 0.02%
(6) Store the raw material sealed, using moisture-proof packaging
핵심 요약
Excessive moisture content of the raw material is solved by full drying, and a sound drying and storage management system needs to be established.
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