玻璃微熱壓之成形特性研究

Abstract

玻璃在常溫下能保持一定的外形，其機械性質類似於同組成的晶體。玻璃的硬度較高，脆性較大，破碎時往往具有貝殼狀的破斷面，且透明性良好，表明從外觀特徵上判斷玻璃屬於固體，但從微觀結構來看，其特徵為”遠程無序”和”近程有序”，又類似於液體，所以玻璃之成形加工也異於其他之工程材料。而微熱壓製程是發展微機電系統時製造高精度高品質微結構的重要成形技術之一，透過此成形之技術，可大量翻造出品質均一，且具高精度的產品，目前已廣泛應用於鏡片等之生產。 玻璃之微熱壓成形過程中由於其可塑造之溫度範圍狹窄，又具有脆性，不當的製程參數組合，容易產生收縮、黏滯、龜裂、轉印精度不良等缺陷。在本研究中，我們以玻璃為材料針對壓印溫度、壓力與時間等參數進行一系統化的微熱壓成形實驗，觀察其成形缺陷並比較在不同參數條件下玻璃之轉印性並觀察，檢視其缺陷、外型尺寸精度，藉以瞭解溫度、壓力、時間等參數與缺陷出現之關係，進而訂出光學玻璃微熱壓成形之較佳工作條件，提高玻璃微細元件應用之可行性以及在微米級尺寸的玻璃成形特性。 實驗結果顯示，FCD1與SF2玻璃適合的壓印溫度在轉移點以上、軟化點附近，壓印力需大於15MPa，充填時間180秒以上；而壓印深度與溫度及壓力成正比，與玻璃厚度成反比。

At room temperature, most glasses are hard, brittle, their fracture surfaces are not smooth. At certain wavelength, glasses are transparent, they look like solid in appearance, however, from the viewpoint of microstructure, they are similar to liquids. Thus the processing of glasses are different from other engineering materials. Hot embossing is one of the forming technique used for the manufacturing of lens and the optical glass components. This technique produces high quality glasses products with very low cost. As mentioned earlier, glasses are breakable, the temperature range suitable for forming are very narrow, improper combination of process parameters induces shrinkage, crack and unacceptable imprinting of the form. In this study, we chose glasses as experimental materials, investigate the factor of embossing temperature, pressure and holding time`s effect on the occurency of defects, establish their relationship and hopefully find out the most suitable combination of these processing parameters for the production of micro scale glasses components. It is found that the suitable embossing temperature for FCD1 and SF2 glasses is between the transformation temperature and softening temperature, the embossing pressure must be larger than 15 MPa, and the embossing time needs at least 180 seconds. The embossing depth is proportional to temperature and pressure, and reverse proportional to the thickness of glasses.