- 學位論文
光學薄件射出成形之殘留應力研究
A Study of Residual Stress of Optical Thin Plates by Injection Molding
摘要
光電產業的發展使產品設計趨向於更輕、更薄與更小，塑膠射出產品的運用也就越來越多，除了考慮光學的性能之外，塑膠本身所造成的影響也不可忽略，因此本研究目的為探討不同的射出成形參數對塑膠光學元件殘留應力的影響。研究先利用模流分析軟體設定不同參數分析其翹曲量，配合田口法找出較佳之成形參數供實際射出成形實驗，再經由軟體計算應力值代入迴歸分析，發現迴歸方程式得到的預測值與實驗值非常接近，僅有0.05%的差異，影響殘留應力的因子為模具溫度與冷卻時間；而翹曲迴歸方程式得到的預測值則有3.6%的差異，影響翹曲量的因子為保壓壓力與冷卻時間。另外並對射出成品進行退火實驗，發現經由退火處理的成品其殘留應力比起未經退火處理的成品減少了1~3%。實驗結果顯示實驗數據與迴歸方程式差異不大，利用此方程式可預測射出成形之殘留應力，因本實驗成品為一小尺寸PMMA薄件，未來可進一步探討含微結構或大尺寸光學薄件成品的殘留應力。
並列摘要
Development of optic-electric industry makes the trend of design product thinner and smaller, and also with widely applications of plastic injection parts. Not only the manufacturer or designers have to consider the defects of plastic parts, but also the optical properties. This research is to investigate the residual stress of optical plastic parts caused by different injection molding parameter. First the moldflow is used and set different parameters to simulate the warpage, and then Taguchi method is used to find appropriate injection molding parameter for experiment. Residual stress has been calculated for regression analysis. From the result of regression analysis, the simulated data has 0.14% difference from experiment data of stress and the major parameters for residual stress are mold temperature and cooling time. The simulated data compared with experiment data of stress after annealing almost have no difference, the simulated data compared with experiment data of warpage has 3.6% difference and the major parameters for warpage are packing pressure and cooling time. Result of the stress before and after annealing has 1~3% difference. Result also shows that experiment data compared with regression model has little difference; therefore, the regression model can be used to predict residual stress from injection molding. Since the part of this experiment is a small thin plate with PMMA material, further research investigates residual stress of optical thin plate with larger dimension or micro features.