智能化精微工具機開發與光學玻璃微結構加工研究

Abstract

光學玻璃因為其優良的物理、電子及光學性質因而受到廣泛的應用，如智慧型手機、相機等各種消費型3C產品。光學玻璃雖有上述優秀的特性，不過當進行切削或移除時，往往會產生無法預測的脆性破壞，這是長期困擾著產業界的難題，也是光學玻璃無法更加普及使用的原因。本研究旨在開發一部「智能化精微工具機」，主要目的是針對光學玻璃(BK7)、金剛玻璃(Gorilla glass)及石英(Quartz)等硬脆材料，進行精微切削技術的開發。為避免硬脆材料加工時產生脆裂破壞及微細裂紋，本研究提出一原創概念—在工具機上設計切削阻抗感測裝置，感測切削受力大小，並依受力迅速回授調整切削進給速度，使工具機具類人化回饋機制，以達「智能化(Intellectualization)」設計目的，提升加工品質。透由實驗測試，本研究所提方法，證實能有效保護光學玻璃免於脆性崩裂，並使切削表面粗糙度由Ra 0.099 µm降至Ra 0.056 µm。因為回饋機制的保護，本研究除了在強度極高之金剛玻璃上成形一深度0.7 mm的條狀溝槽，亦成功在石英玻璃上成形一高度0.3 mm的微型金字塔。相較於設備成本高昂的超音波工具機，本研究開發之工具機具容易控制且低成本的優點，深具市場競爭力。

Optical glass is widely applied in smart-phones, digital cameras and other consumer-oriented electronic products because of the excellent physical, electronic and optical properties. However, it is difficult in material removal resulting from an unpredictable brittle fracture. Brittle fracture such optical glass cannot thus be employed extensively. The primary purpose of the thesis is to develop an intellectualized machine tool and using the finished machine tool to fabricate microstructure on optical glass as BK7, gorilla glass and quartz. To avoid brittle fracture damage and micro cracks, a sensor (feedback) mechanism made with a three-axis load-cell constantly detects the drilling force is proposed to give real-time feedback to regulate the feed-rate. Grinding-drilling is applied whereby the diamond tool slowly mills into the glass grinding layer by layer. By applying the human-like feedback mechanism, the machine tool can achieve an intellectualized machining and improve the processing quality. Experimental results demonstrate that the designed feedback mechanism can provide an effective protection against abrupt cutting force. The roughness of grinding surface can be accomplished from Ra 0.099 µm down to Ra 0.056 µm. A precision bar-shaped groove with 0.7 mm in depth and a micro tower with 0.3 mm in height can be finished on a toughened gorilla glass and quartz, respectively. Compared to commercial machine tool with ultrasonic vibration-assisted, this development is simple and cost-effective.