單點鑽石車削雙曲率模仁表面改善之研究

Abstract

各產業的科技產品精度要求日益提高，因此製造高精密度之零組件為現在加工的重要課題。隨著科技發展與3C產品的普及，世界上近視人口不斷的提高，對於光學鏡片之需求也日益提高， 因為光學等級模仁所需要的加工精度極高，目前大多採用研磨與拋光的方式加工，其製程非常耗時且模仁表面之形狀精度難以控制，且只能加工對稱型模仁，產品變化性受到極大的限制，針對非對稱型工件，需要使用超精密加工機才能加工，如雙曲率模仁，其運用於近視閃光鏡片。但超精密加工在加工過程中容易在模仁表面彩虹紋等表面瑕疵，使得模仁表面雖然為鏡面，但表面粗糙度上升，造成產品之成像品質下降。本研究主要針對超精密加工雙曲率模仁時容易在工件表面留下彩虹紋之問題進行探討，分析彩虹紋產生之原因然後針對其成因提出一特殊夾治具，使其加工雙曲率模仁從正面之C-X-Z三軸加工轉變為側面X-Z兩軸加工，利用夾治具改變其加工路徑，使加工過程免除Z軸在加工非對稱型模仁時之往復運動所造成的誤差。研究結果顯示，利用夾治具改變成側面加工之方法主要可以降低Z軸往復運動時造成之運動誤差，使表面粗糙度下降，消除彩虹紋提高產品成像，達到產品規格Ra小於10 nm，形狀精度小於2 μm且鏡面沒有彩虹紋之標準。同時利用側向加工方法因Z軸不需做往復運動，使得主軸轉速可以大幅提高，因此可以降低加工時間使產能提高數倍之效率。本研究實驗結果利用釐清彩虹紋發生之成因且利用夾治具之設計成功解決非對稱型工件容易產生彩虹紋之問題。

The precision of technological product in every industry is required to be better. Therefore, making high precision products has become a significant topic in manufacturing. Following future technology grow with 3C product In our world nearsighted keeps on increase. Regarding the sun lens demand is increase daily. Optic level mold needs ultra precision machining, so usually publishing and lapping process is applied to it, the process takes extra time and the roughness of the molding surface is hard to control. And also it only can manufacture mode with symmetry. The variability of product has limit. The unsymmetrical products need to manufacture by precise machine. Ex: double curvatures mold. This project aims to investigate the production of rainbow waviness on the surfaces of the mold. Rainbow waviness will reduce the surface roughness and the form accuracy during the usage of the ultra precision machining. The formation and the occurance of the rainbow waviness will be speculated and analysed in order to produce a specialised jig,taking advantage of the jie to change it .While taking advantage of the lateral approach due to the Z-axis machining without reciprocating, making the main axis spindle speed can be significantly improved, thus reducing the processing time for the production capacity several times greater than the efficiency .The results of this experiment successful design of the jig to solve rainbow waviness.