本文探討銑刀刀腹犁切機制下產生的製程阻尼對銑削製程中臨界切深曲線的影響，並提出其預測流程。首先在零階近似模式下利用含製程阻尼非線性之系統特徵方程式，觀察其對刀尖結構動撓度之奈氏圖變化，發現在製程阻尼效應增強時，低頻部分變形程度勝過高頻部分。接著導入製程剛性與刀尖結構動撓度相交且相位落後前刃180°之概念繪製穩定葉瓣圖，結果顯示臨界切深曲線在低切線速度有拉抬效應，與過往文獻相符，亦觀察到在特定切線速度下，隨軸向切深提高，銑削穩定性會變換數次。
　　銑削穩定性變換源自製程阻尼對刀尖結構動撓度的影響，進而造成穩定葉瓣變形，並在低切線速度區因製程阻尼過強使葉瓣變形嚴重且擁擠，導致臨界切深曲線呈現”Z”字形輪廓。此外，Z形臨界切深曲線中，Z形上枝顫振頻率低於刀尖結構模態自然頻率，此現象可藉由零階近似解析式與數值模擬驗證。最後，為求此非線性系統特徵方程式之近似解，本文提供一流程建立Z形穩定圖，並以實驗驗證Z形穩定圖之現象。

　　This study investigates the effect of process damping produced by ploughing mechanism on tool flank on critical depth curve, and a prediction model is proposed. First of all, based on Zero-Order Approximation, realizing the Nyquist plot of tooltip receptance with process damping and distortion in low frequency parts exceeds high frequency parts. Then, Stability lobes diagram can be constructed by intersection of two parameters, stiffness receptance and process receptance, which abbreviated to Rs and Rp and by the concept that phase lag of previous cut equals to 180 degree. Results show that critical depth of cut lifts in low cutting speed, having a good agreement with previous studies. In addition, the stability state may alternate several times with an increasing axial depth at given cutting speed.
　　Alternation of stability originates the deformation of stability lobes due to effects on tooltip receptance. Moreover, strong process damping in low cutting speed makes lobes crowded and be out of shape, leading a “Z” shaped stability diagram. However, chatter frequency is lower than modal frequency of tooltip on upper branch of Z, it can be proved by ZOA and numerical simulation. At last, in order to solve this nonlinear characteristic equation, this thesis provide a process to build Z-shaped stability diagram and experimentally validate it.

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