超音波輔助玻璃微結構熱壓成形研究

Abstract

玻璃熱壓成形技術是玻璃光學元件重要的製程方式，近年來由於玻璃熱壓成形技術的蓬勃發展，更是向下延升為玻璃熱壓微結構成形技術，大幅降低了玻璃微光學元件製程成本。而超音波振動輔助已經廣泛應用於塑性加工，藉由摩擦力的降低、材料溫度升高...等現象，使得材料成形性提高，提昇加工精度及降低成本。因此本研究嘗試將超音波輔助應用於玻璃微結構熱壓成形。 本研究首先利用有限元素軟體，考慮超音波放大器在高溫下的材料特性，設計可在高溫下使用之超音波放大器，接著利用熱壓成形設備進行玻璃熱壓材料試驗，結果證明了玻璃材料受到超音波振動之後，材料發生軟化情形，可降低成形時所需之應力。後續利用電鑄翻模製作具有Fresnel結構之鎳鈷合金模仁，以及利用放電加工於不□鋼表面製作V溝結構模仁以及球形陣列模仁，再使用製作之微結構模仁進行超音波輔助玻璃微熱壓成形實驗，結果顯示超音波的施加對於填充性具有顯著的提升。

Glass hot embossing is an important technique for optical elements fabrication in recent years. It is generally used to manufacture optical lenses with the advantages of low-cost and steady quality. The same technique is also applied to mass produce microstructure optical glass elements by using molds with microstructure surface. In the same time, the ultrasonic assisted manufacture is widely used in plastic forming in recent years. This technique can raise the precision of products as well as reduce the cost of manufacture. Therefore this research focuses on applying the ultrasonic assisted technique on the hot embossing of glass with surface microstructure. In the beginning of this research, finite element simulation was adopted to design an ultrasonic horn workable in high temperature range with temperature gradient. Then material tests were conducted with the improved ultrasonic assisted hot embossing apparatus, and the results indicated that the glasses were softened with the application of ultrasonic vibration, so the forming loads can be reduced. Furthermore, several molds with surface microstructures for glass hot embossing were manufactured. The fresnel structure mold was made by electroformed Ni-Co alloy, and the electric discharge machining was adopted to manufacture both the V-groove mold and the ball grid array mold. The microstructure glass hot embossing experiments were then performed with these manufactured molds. The results show that, during hot embossing process, the fillings were improved significantly with the assistance of ultrasonic-vibration.