車床用從動刀架之改良設計

The Modification Design of the Follow Rest for Turning

本研究是針對現有之車床用從動刀架予以改良，利用彈簧吸收振動能量，以增加阻尼效果，提高工件之動態剛性，避免顫振發生，以獲得良好之工件表面粗糙度值。經由實驗發現，利用本研究所改良之從動刀架，對於細長工件（例如細長比L/D=18）之車削加工，不僅看不到顫振現象，表面粗糙度非常良好，而且切削速度可以提高到短工件（例如細長比L/D=2.5）精切削時之切削速度；由此顯示本研究之改良設計具有很好之顫振抑制效果，而且花費不多，因此亦具有很高之實用價值。

This study is directed to the modification of the design of the follow rest for turning. By using a spring to absorb vibration energy, one can increase the damping ratio and also increase the dynamic rigidity of the workpiece. From the experimental results, we found that the surface roughness of the workpiece was very good and that chatter was not found. When turning the slender workpiece (slender ratio is 18), the cutting speed also can be increased to the same speed as for a short workpiece (slender ratio small than 5). It is indicated that the design modification had a very excellent chatter suppression effect. The cost was also very cheap, so it is a very useful design.