高頻振動輔助之智能化臥式精微工具機開發與Zerodur®陶瓷玻璃奈米研銑加工研究

Abstract

本研究主要目的係針對Zerodur®陶瓷玻璃硬脆材料，開發智能化研銑加工技術。Zerodur®陶瓷玻璃具極低的熱膨脹係數，良好的物理性質與化學穩定性，適用於航太科技與各種高端精密產業元件。但由於Zerodur®陶瓷玻璃的硬脆性質，加工過程極易造成脆性破壞。為使Zerodur®陶瓷玻璃能在延性模式下加工，本研究提出一種「高頻振動輔助之智能化臥式精微工具機」的原創設計，這項設計結合自行開發的「含硼聚晶鑽石研銑刀具」、「高頻振動輔助加工」與「智能化研銑力判斷機制」等技術，使Zerodur®陶瓷玻璃能在奈米深度下進行研銑加工。為避免研銑過程中發生脆性破壞，研銑力分別以「荷重元」及「平台電流」進行線上偵測，並依回授的研銑力調整刀具進給率，透由「智能化」機制判斷，使陶瓷玻璃能在非脆性破壞模式下加工。實驗證實，本研究所提智能化研銑技術，能有效減少Zerodur®陶瓷玻璃的脆性破壞發生，並改善加工面粗度，刀具平均磨耗率可降至0.005µm/mm。此外，實驗也發現，研銑過程中導入高頻振動輔助，除了能幫助切屑排除外，更能使表面粗糙度降至Ra0.388µm，並減緩研銑刀具的磨耗至0.002µm/mm程度。一個成功的微小立方體的Zerodur®陶瓷玻璃加工實例，驗證本研究所開發的整合型技術，著實能提供Zerodur®陶瓷玻璃在延性模式(Ductile regime)或類延性模式(Quasi-ductile regime)下加工，且製程所需成本低，容易控制，深具商化價值。

The primary purpose of the thesis is to develop an intellectualized milling-grinding technique for machining ZERODUR® glass-ceramic. ZERODUR® glass-ceramic which owns an extremely low coefficient of thermal expansion, excellent physical properties and chemical stability is very suitable for the fabrication of various micro components in aerospace and high-precision optical industry. However, brittle fracture will be easy occurred following the progress of machining such as brittle material. To machine the ZERODUR® glass-ceramic under ductile or quasi-ductile regime, an intelligent horizontal micro machine tool is developed and proposed in this study. The innovation combines a home-made boron-doped polycrystalline composite diamond (BD-PCD) tool with high-frequency vibration assisted machining and intellectualized milling-grinding force detection. The machining force measurement via the designed load-cells and the stage-current to on-line detect the force coming from machining resistance of the glass-ceramic workpiece for self-regulating the tool’s feed-rate is recommended. Milling-grinding can be implemented favorably under a non-brittle fracture regime. Experimental results indicated that the intellectualized milling-grinding technique decreases evidently the probability of brittle fracture of the machined glass, improving its surface roughness and reducing the tool wear rate down to 0.005µm per mm. Besides which, the high-frequency vibration assisted machining is also confirmed that can help in sending out the debris, improving the surface roughness (Ra 0.388µm) and alleviating the tool wear rate (0.002µm per mm). How the self-regulating feed-rate works is carefully examined and verified in the manufacture of a miniaturized cube on ZERODUR® glass-ceramic. It is demonstrated that the proposed integrated technique can achieve a machining on ductile or quasi-ductile regime on the hard-brittle glass-ceramic. The technique is inexpensive and easily controllable, which is worthy of commercialization.