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標題: | 微銑削薄壁型Ti-6Al-4V工件尺寸誤差之研究 Study of Dimensional Error in Micro Milling Ti-6Al-4V Thin Wall |
作者: | Ping-Chun Huang 黃品鈞 |
指導教授: | 廖運炫 |
關鍵字: | 微銑削,鈦合金,薄壁工件,尺寸誤差,超音波振動輔助,順逆銑, micro milling,titanium alloy,thin wall,dimensional error,ultrasonic vibration-assisted milling,up/down miiling, |
出版年 : | 2013 |
學位: | 碩士 |
摘要: | Ti-6Al-4V具有優異的抗腐蝕性和物理、機械性質,被廣泛運用在生醫領域。本研究探討微銑削寬度0.2 mm、高度2.0 mm,寬高比為10薄壁尺寸誤差量的誤差成因分析與改善策略。本文以有限元素分析探討薄壁工件撓曲變形量成因,模擬結果顯示,隨著薄工件厚度減小,剛性逐漸降低,切削力占變形的比重逐漸上升,而切削熱影響變形的比重過低可以忽略。目前學術研究上,對於薄壁銑削加工適合用順銑法或逆銑法,有著不同的看法。順銑削表面佳易加工,本文先以不同切削速度、進給、切削液搭配進行實驗,得出了在切削速度95 m/min、加工進給3 μm/tooth、切削液MQL下,較原始切削參數下,平均尺寸誤差量小了約49 %;逆銑削表面不佳,表面上有缺陷,本文先探討其產生原因,並且以噴灑MQL、增加0.09 mm預留量、降低切深至0.3 mm等策略,成功切削出表面良好的薄壁件,使其可排除表面因素,進行尺寸誤差量測。相同的參數比較順銑削、逆銑削尺寸誤差量,兩者之間並無太大的差距。最後以本文將以切削力造成刀具撓曲與工件撓曲之間的交互關係為基礎,提出一順銑削與逆銑削的薄壁尺寸誤差模型,並且以實驗驗證之,成功地解釋順銑削、逆銑削薄壁件尺寸誤差的來源。加工策略方面,提出以超音波輔助振動銑削的方式,降低切削力,同時降低薄壁尺寸誤差量,在進給方向進行頻率25,000 Hz、震幅5 μm的一維振動,並且以實驗成功證明可降低側向切削力,在超音波振動輔助順銑削搭配MQL下,側向切削力降低31%,平均尺寸誤差量降低28%。超音波振動輔助逆銑削搭配MQL下,表面橫條紋明顯變少,但是仍然無法全部清除。 Titanium alloy (Ti-6Al-4V) has been widely used in biomedical field due to its superior mechanical properties, corrosion resistance. The research investigated dimensional error by micro milling a titanium thin wall, with 2.0 mm height and 0.2 mm thickness. In this study, a finite element analysis was applied to analyze the cause of deformation. The result of the analysis shows that cutting force is the main factor in deformation when the workpiece becomes thinner. Paper review shows that it has been widely discussed up/down milling thin walls. Down milling is easier to produce thin walls with wide cutting parameters. Dimensional error decreased 50 % with 95 m/min cutting velocity, 3 μm/tooth cutting feed, MQL cutting fluid. On the other hand, up milling produces thin walls with bad surface qualities. By observing and analyzing the reason of these surfaces, good surface qualities was produced by up milling with MQL cutting force, 0.09 mm tolerance, 0.3 mm axial depth of cut which was able to measure dimensional error. The measurement results of up milling and down milling with the same parameters show that there are no differences in dimensional error between these two strategies. In this study, a up/down milling thin wall deflection model was established to explain the result of the dimensional error above. At last, an ultrasonic vibration-assisted platform was established which supplied an one-dimensional vibration with 25,000 Hz frequency, 5 μm amplitude. It was proved that with MQL and ultrasonic vibration assisted down milling, normal cutting force and average dimensional error decrease 31%, 28% respectively. With MQL and ultrasonic vibration assisted up milling, transverse stripe was decreased obviously, but could not be removed completely. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/60188 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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