含硼聚晶鑽石輪刀開發與繞射階梯光柵模仁製作研究

Abstract

本研究旨在開發一傾斜式高速快淺研削技術(High speed& fast shallow grinding)，並應用於繞射階梯光柵(Diffractive echelle grating)模仁的製作。主要目的是為提高繞射階梯光柵製作技術之加工效率與降低其製作成本。研究之初，設計並開發含硼聚晶鑽石(Boron doped polycrystalline composite diamond, BD-PCD)圓盤刀具，透過錐度彈簧套筒設計，使含硼聚晶鑽石刀片與刀軸同時獲致自動對心與鎖固功能。為減少圓盤刀具於放電加工修整時，切刃邊緣因尖端放電而發生的角隅磨耗，本研究提出一種「犧牲電極(Sacrificial electrode)」的策略，使放電電場均勻化，抑制尖端放電現象，以提高刀具角隅精度。此外，為使鑽石輪刀依光柵閃耀角傾斜一角度，以進行傾斜式高速快淺研削加工，本研究開發一加工軸傾角研削模組，並提出對光柵閃耀角的共向研削法，可有效抑制研削延性材料(Ni-P合金)的毛邊生成。而透由優化後的加工參數，亦可於碳化鎢材料上，成功創成光柵常數2.75 μm至8 μm的繞射階梯光柵微結構，且具優異之分光效果。The main purpose of the thesis is to develop a technique of inclined high-speed& fast shallow grinding and use in generation of diffractive echelle grating mold to enhance the processing efficiency and decrease the cost for grating mold production. First, a wheel-tool made of boron-doped polycrystalline composite diamond with a sharp corner is schemed and machined. A spring collet which possesses a taper of 1:4 is designed to provide for assembly auto-center between the tool and shank. To avoid the corner wear of wheel-tool during forming, a strategy of sacrificial electrode employed is proposed. This is helpful in making a uniform electric field and suppressing localization at tool-end region to obtain more accurate machining. In addition, a set of inclined clamping mechanism which can stably locate a high-speed spindle to guide the wheel-tool to grind along the blaze angle of grating is developed. A co-direction grinding, in which grinding is carried out along long side of grating and normal direction of blaze plane is proposed to restrain burrs from occurrence. Experimental results demonstrate that the inclined high-speed& fast shallow grinding with co-direction grinding can generate micro grating array with grating constants of 2.75, 4.0 and 8.0 µm, respectively. These machined diffractive echelle grating array can really achieve the separation of light for different wavelengths.