Molds & Tooling
4 조회수
Sink marks on thick-wall PP parts (freeze-off type)
문제 현상
The holding pressure time for thick-wall PP parts has been set very long, but the sink marks are still obvious, and extending holding pressure is ineffective.
원인 분석
The gate is too small and freezes off early, so the holding pressure can no longer be transmitted to the thick-wall area, and no matter how long the holding pressure time is, it is 'ineffective holding pressure'; the shrinkage of the thick-wall core is not compensated and the surface dents.
해결 방법
①Appropriately enlarge the gate to delay the freeze-off time; ②arrange the gate near the thick-wall area; ③core out the thick-wall area to reduce material and shrinkage; ④conduct a gate freeze-off study to determine the effective holding pressure window; ⑤add auxiliary gates when necessary.
핵심 요약
For PP thick-wall sink marks, first check 'gate freeze-off': after freeze-off, holding pressure is given for nothing; enlarging the gate, moving it closer to the thick wall, or directly reducing material is far more effective than blindly extending the holding pressure time.
이 정보가 도움이 되었나요?
0 명이 도움이 되었다고 합니다
의견 주셔서 감사합니다!