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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/2819


    Title: 304不銹鋼之摩擦鑽孔特性研究;Characteristic study on AISI 304 stainless steel using friction drilling
    Authors: 李新民;Shin-Min Lee
    Contributors: 機械工程研究所
    Keywords: 摩擦鑽;摩擦鑽孔;無屑加工;乾式鑽孔;不銹鋼;friction drill;friction drilling;chipless machining;dry drilling;stainless steel
    Date: 2008-10-10
    Issue Date: 2009-09-21 11:57:02 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 摩擦鑽孔係藉由摩擦生熱的原理加工成形,具有無屑加工及乾式加工的特性。在金屬薄板熱摩擦鑽孔後,可形成3 ~ 4倍工件厚度的軸襯,可以提供後續攻螺紋的內孔,節省焊接螺帽的製程。沃斯田鐵系的不銹鋼材料,具有高韌性、熱傳導係數低及加工硬化等特性,使得一般的傳統麻花鑽頭,對於鑽削這類難加工材料,都會造成刀具的急速磨耗,甚至崩裂,大幅縮短刀具的壽命。但是不銹鋼材料擁有極佳的抗蝕性及抗磨耗性,因此在工業上廣泛的應用並扮演著重要的角色,所以有許多的研究,仍然繼續不銹鋼的鑽孔加工探討,以尋找出最佳的刀具材料、刀具形狀或是加工參數,以改善目前對於不銹鋼材料鑽孔加工的窘境。研究顯示,以進給率100mm/min,轉速1200rpm,比較鍍TiN高速鋼鑽頭、碳化鎢鑽頭與摩擦鑽的磨耗發現,摩擦鑽比其他兩組鑽頭具有更長的刀具壽命。藉由田口實驗法顯示,摩擦鑽錐角度30o,摩擦接觸率50%,進給率100mm/min,轉速3600rpm時,能得到最佳的孔壁表面粗糙度。加工孔橫段面的硬度,以愈接近孔壁邊緣,其硬度值愈高。摩擦鑽的披覆實驗結果顯示,由於固態潤滑效果及熱傳導係數的影響,使得AlCrN披覆層的摩擦鑽頭,測得的鑽頭磨耗及軸向力小於TiAlN披覆與非披覆的摩擦鑽。在不銹鋼摩擦鑽孔加工及其材料強化研究上顯示,微量潤滑鑽頭所加工的材料,要比乾式鑽頭具有更高的硬度產生。 Friction drilling utilizes the heat generated from the friction between the tool and the workpiece for machining. This process produces no chip, shortens the time required for hole-making and incurs less tool wear, thus lengthening the service life of the drill.After the friction drilling operation had been conducted, a thin plate (workpiece) was formed into a bush with a thickness of 3 times larger than that of the workpiece. The bush can provide a longer area of contact which can fit a shaft firmly. The bush can also be taped to create an internal screw without welding a nut.In this study, tungsten carbide drills with and without coating were employed to make holes in AISI 304 stainless steel, which is known to have high ductility, low thermal conductivity and great hardness.After the optimal drilling parameters of friction drilling were obtained, the optimal geometric shape and friction contact area ratio of the friction drill was selected to conduct experiments and compare with the traditional HSS twist drill coated TiN and Tungsten carbide drill. The results showed that HSS coated TiN was damaged seriously after two drilling runs and Tungsten carbide was already to create a serious wear of drill edge after three runs. However, the friction drill showed little wear and still can normally drill the AISI304 material after 60 runs. Therefore, the friction drill has a better performance than both the HSS coated TiN and the Tungsten carbide drill. Furthermore, the friction drill avoids serious tool wears, enhances drilled hole quality, and prolongs the tool life more significantly. TiAIN and AlCrN were coated onto the drill surface by physical vapor deposition (PVD). Performance of coated and uncoated cutting tools were examined for drillings made under different spindle speeds. Changes in relationship between drill surface temperature, tool wear and axial thrust force during machining were also explored. Experimental results reveal that lubricating effect of the coating and low thermal conductivity of AlCrN caused AlCrN-coated drill to produce the highest surface temperature but the lowest axial thrust force with the least tool wear. However, the difference in performance between coated and uncoated drills diminished with increase in number of holes drilled.
    Appears in Collections:[機械工程研究所] 博碩士論文

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