Warpage Control of Thin-walled Injection Molding for Handy Communication Devices

[[abstract]]目前3C產品趨勢逐漸走向薄殼化以強調產品的輕便特性，因此以射出成型做為薄殼產品的量產技術，產品形狀的收縮和翹曲控制攸關後續組裝時的難度及組裝後產品之品質。形成薄殼成形翹曲的原因很多；如成品厚度不均、模具冷卻不一致、或澆口位置設計不當等皆是。為了解薄殼射出成型品之翹曲變形問題，本文以非對稱掌上型平板外殼成形為載具，透過澆口位置的配置與水路設計的優化，排除因成形條件或模具設計不良造成翹曲變形的問題。另外，目前業界在薄殼成形以公模或母模做單一模溫的設定，無法有效改善成形翹曲問題；而且傳統的對稱式水路設計亦限制了模溫調整的空間，所以易產生控制了一端的翹曲，另一端卻無法隨之改善的現象。本研究運用CAE模擬分析技術，提出以中立軸理論的概念分析肉厚方向的溫度分佈，以預知產品翹曲的趨勢。然後找出理想的澆口位置的設計及合適的模溫設定，將可有效地提昇成形品質並減少產品開發時間。另外為使模擬結果更具有說服力，將模具開發完成後，能以實際射出的成品用來驗證模擬結果的證據，透過實際射出成品進行尺寸精度量測。[[abstract]]The trend of 3C products nowadays is less heavy and better handy Injection molding as one of the most used techniques for mass-production in industries also faces a challenge to produce a thinner product with free of shrinkage and warpage The causes of warpage in thin-walled molding are many such as product geometry with inconsistent thickness mold with uneven cooling performance and a poor sprue-runner-gate system For handy communication devices the excessive warpage directly produces a non-expected shape of components and further causes poor quality of products during and after assembly Consequently this study employs an asymmetric shaped cover of handy communication devices as a research carrier and aims to optimize the process parameters and cooling design to exclude poor warpage Additionally conventional setting of unique mold temperature for the male or female mold plates is insufficient to improve warpage Besides traditional symmetric design of cooling channels can limit the ability of mold temperature adjustment Thereby a neutral axis theory for analyzing temperature distribution along the thickness direction to predict the trend of warpage is proposed in this study Through CAE simulation an ideal gate-runner system coped with optimal mold temperature setting can be obtaine