玻璃自重成形之有限元素分析

Abstract

玻璃自重成形製程逐漸地被使用在先進玻璃產品上，例如抬頭顯示器、智慧型手環上使用的曲面玻璃鏡片。鏡片的加工精度、光學性質為影響品質的重要因素。本研究之目的將以智慧型手環曲面玻璃鏡片為載具，設計一曲面玻璃鏡片自重成形的實驗與有限元素分析方法。 首先進行成形溫度實驗取得製程溫度參數，接著進行鍍膜層效果測試。另一方面，建立有限元素模型預測玻璃自重成形，並進行成形過程實驗，比較實驗與模擬的結果來驗證模擬的準確性。 成形溫度實驗部分，考量玻璃成形完整性與製造的實用性，使用520℃作為自重成形的最佳製程參數。使用氮化硼塗層能達到抗沾粘效果，雖然表面平面度不足，可仍用於初步研究上，相較之下，類鑽石與鉑鍍膜層在溫度超過520℃以上的製程中效果不彰。有限元素模型可以模擬自重成形中玻璃溫度場變化與成形過程。比較成形過程實驗結果與有限元素模擬亦有相同趨勢，驗證了有限元素模形的準確性。

關鍵字：曲面玻璃鏡片、玻璃自重成形、有限元素分析

Glass sagging process is gradually used in high-tech glass products such as the curved glass lens on the head-up display and the smart band. Manufacturing precision and optical properties are the key to the quality of glass lenses. Based on curved glass lens on the smart band, the purpose of this study is to establish an experiment and analysis method of glass sagging process. At first, the temperature experiment is finished to get the best temperature parameters. Then, testing the effect of three kinds of coatings. On the other hand, a finite element model is constructed to predict the forming procedure, and the forming experiment is accomplished. In the end, verify the accuracy of finite element model by comparing the results between simulation and experiment. In the temperature experiment, concerns about the completeness of forming and the feasibility in manufacturing, setting 520 Celsius degree to be the best forming temperature. NB coating can avoid sticking problem, it can be used in the early stage of research though the poor flatness it has. By contrast, DLC and Pt coatings do not work with high forming temperature. The finite element model can simulate the temperature distribution and the displacement of glass in sagging process. Compare the forming experiment result and finite element simulation, the change of glass shape depends on time have similar tendencies. It proves the accuracy of the finite element model.

Key word：Curved glass lens、Glass sagging、Finite element analysis