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標題: 減振搪刀桿之可行性研究
Feasibility Study of a Vibration-Reduction Boring Bar
作者: 莊集黃
Juang, Ji-Huang
關鍵字: vibration;振動;boring bar;damp;搪刀桿;阻尼
出版社: 機械工程學系
切削加工為產業最基本的加工技術之一,而刀具與工件間的相對振動為影響加工精度之重要因素,其中刀具之結構特性佔一重要角色。本研究針對細長搪孔刀具之刀桿,探討藉由改良刀桿內部結構特性以改善其動態切削性能之可行性。研究先由文獻之探討分析切削振動之類別及其成因,作為設計減振刀桿之依據,進而採用增加結構阻尼的方式來改善刀具之切削特性。研究中在刀桿內部置入質量塊以及傳遞與吸收能量的彈簧,藉由調整彈簧壓縮量以改變搪刀桿的阻尼特性,所設計之刀桿並經法有限元素法分析其結構特性,再進一步試製所設計之刀桿,並透過靜態激振實驗以及動態切削實驗以測試該設計的改善效果。測試結果顯示所設計之改良刀桿在受拘束狀況下其系統等效阻尼比一般刀桿由原來之0.66%提升到4.02%,共振頻率由711Hz降到589Hz,轉移函數由3.02×10-5 m/N降到1.37×10-5 m/N,以切削寬度0.07mm為條件,其切削長徑比可由原一般刀桿之6.5提升至7.5而不產生顫振,證實本研究所設計之搪刀桿可有效提升切削之減振效果。

Cutting process is one of the most fundamental fabrication technologies for industry. The relative vibration between the workpiece and the tool, in which the structure characteristics of the cutting tool play a crucial role, is an important factor affecting the precision of workpiece. This research is aimed to improve the dynamic cutting characteristics of a slender boring bar through modifying its structure characteristics. Vibrations in cutting are first analyzed as a foundation for structure modification. It is then determined to improve the cutting characteristics by increasing the damping of the boring bar. A mass block and a spring for absorbing energy are inserted into the bar. Damping is adjusted by compressing the spring. Structure characteristics of the designed boring bar are analyzed by finite element method. The fabricated boring bar is then tested under a structure dynamics test and dynamic cutting tests. The test results showed that the equivalent damping ratio of the boring bar increased from 0.66% to 4.02% while the resonant frequency changed from 711Hz to 589Hz. Amplitude of the transfer function reduced from 3.0210-5 m/N to 1.3710-5 m/N. The length/diameter ratio of the boring bar increased from 6.5 to 7.5 without chattering under the width of cutting at 0.07mm. These results showed the designed boring bar effectively increase the capability for vibration reduction.
Appears in Collections:機械工程學系所

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