薄件射出成形之翹曲分析

Warpage Analysis for Injection Molding of Thin Plates

羅煜清(Yu-Ching Lo)

指導教授 ： 陳炤彰 ； 賴明鈞

國立臺北科技大學/機電學院/精密機構設計產業研發碩士專班/碩士(2008年)

https://doi.org/10.6841/NTUT.2008.00515

摘要

翹曲變形存在於射出成品中是造成尺寸不穩定的重要原因，而且對成品的使用性能也會有明顯的影響。一般射出成品發生翹曲的原因大部份為熔膠從高溫冷卻至低溫造成體積收縮，體積的收縮量由比容的變化量來決定，藉由模擬分析熱塑性非結晶性高分子PMMA於不同熔膠溫度、模溫等條件下求得產品之收縮與翹曲變形量。本文模擬之薄型平板長、寬、厚尺寸為20 mm×20 mm×1 mm，熔膠溫度參數為230℃、245℃、250℃，模溫參數為70℃、80℃、90℃之條件下進行分析。模流軟體Moldflow分析射出成形的過程中，高分子由高溫到低溫分別經過液態、半固態至冷卻凝固，將其中的體積變化量估算出成品收縮與翹曲，而應力應變分析軟體ANSYS分析高分子分別於固態及液態時因冷卻而造成的收縮翹曲，藉由二套軟體分析比對數值並估算出高分子於保壓階段造成的收縮率及翹曲率，結果顯示射出成形過程於半固態階段，熔膠溫度250℃、模溫90℃之條件下影響最小，分別於X方向收縮率佔16.63%，Y方向收縮率佔16.22%，Z方向翹曲率佔20%。

關鍵字

射出成形 ； 翹曲 ； 收縮 ； 薄件 ； 半固態

並列摘要

Warpage is the main cause of dimensions of finished products, and also is a signification the performance of finished products. In general, the warpage of finished products is caused by volumetric shrinkage of melt polymer from high temperature to low temperature, and the volumetric shrinkage is decided by variation of specific volume. This research used simulation to analyze the shrinkage and warpage of thermoplastic and amorphous polymer PMMA with different melt and mold temperatures for thin plates 20 mm×20 mm×1 mm . The simulation parameters of this paper are listed as below: melt temperatures as 230℃, 245℃ and 250℃, and the mold temperatures as 70℃, 80℃ and 90℃. In this paper, the mold flow analysis software, "Moldflow" is used to analyze the shrinkage and warpage of finished products which are calculated by the volumetric variation of polymer undergoing liquid state, semi-solid state and solid state. In addition, this research utilizes the stress and strain analysis software "ANSYS" to analyze the shrinkage and warpage caused by the cooling shrinkage of polymer in the solid and liquid states respectively. Then, the results estimated from "Moldflow" and "ANSYS" were used to calculate the volumetric shrinkage and warpage of polymer in the packing stage. Finally, results show that the shrinkage in X-direction as 16.63%, the shrinkage in Y-direction as 16.22%, and the warpage in Z-direction as 20% at the conditions of melt temperature 250℃, mold temperature 90℃, and in semi-solid state in the injection molding process.

並列關鍵字

Injection Molding ； Warpage ； Shrinkage ； Thin Plate ； Semi-Solid

參考文獻

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