本論文之主旨在於應用可變剛性值之撓性夾具輔以振動來探討夾具剛性值對鋁合金A6061-T6之車削加工精度之影響。首先我們利用有限元素法進行可變撓性夾具之結構分析，藉以決定夾具尺寸。接著以線切割加工製作尺寸精度高之可變撓性刀具系統，然後進行撓性振動輔助車削實驗。 根據表面粗糙度迴歸分析可知，當剛性處於中間值時，撓性振動車削之表面粗糙度通常會優於撓性車削。 根據頻譜面積移除率之迴歸分析顯示，當剛性值較小時，小波長面積移除率較大；但在剛性值較大的情況下，大中波長面積移除率較大。 根據切深變化比值之迴歸分析顯示，當剛性值較小時，切深變化比值較大。 The purpose of this thesis is to study the effect of the changeable-stiffness flexible tool fixture on the precision of the turning process of aluminum alloy A6061-T6 with ultrasonic-assisted vibration. In order to attain this end, we used the finite element method for the structural analysis of the changeable-stiffness flexible fixture to determine the dimensions of the fixture. Then we produced the changeable-stiffness tool fixture by using wire electrical discharge machining. According to the surface roughness regression analysis, flexible turning with ultrasonic-assisted vibration can produce better surface roughness than turning without ultrasonic-assisted vibration when operating at intermediate stiffness values. The regression analysis of spectrum area removal rate showed that the small wavelength area removal rate is greater while stiffness is smaller and the medium-to-large wavelength area removal rate is greater while stiffness is greater. According to the regression analysis of the change of the ratio of the depth of cut, we found that the smaller the stiffness is, the greater the change of the ratio of the depth of cut becomes.