The Effects of Centrifugal Deformation on the High-Speed Spindle

[[abstract]]高速主軸係利用盤形彈簧提供適當的拉刀力，經過拉刀拉桿施加於刀把，使刀具能固持於主軸心軸，並確保在切削時主軸有足夠之剛性及扭矩。 本文研究之目的是探討電路板鑽孔機高速主軸，在高達12萬轉的轉速下，旋轉件之離心變形及其對拉刀力、扭矩及彎曲剛性之影響。 首先，確認ANSYS分析結果的準確性，針對轉動件之離心變形或應力，利用ANSYS分析結果與實測值，近似理論值及經驗值等進行比較驗證。接著針對電路板鑽孔機高速主軸，利用ANSYS進行相關性能之分析，包括分析刀具，刀把與心軸組合之彎曲剛性及扭矩，並決定拉刀力。隨後，分析心軸、心軸與刀把、刀把、拉刀拉桿及盤型彈簧之軸向變形。最後，以調整彈簧預壓力，確保主軸在高速運轉時的拉刀力、扭矩及彎曲剛性。[[abstract]]In a high-speed spindle, the Belleville spring is seted to apply put-in force on the toolholder through a drawbar. The toolholder can tightly hold the tool on the rotor of the spindle. Therefore, the spindle provides adequate torque and bending stiffness during machining. This study is aim at the bending stiffness, drivable torque and put-in force of the spindle on the PCB drilling machine, when its rotational speed about 120,000 rpm. First, the accuracy of ANSYS is examined by comparing its result with experiment test result, analytical results and experience formula of centrifugal deformation or stress of spindle parts. Then, the bending stiffness and drivable torque of high-speed spindle on the PCB drilling machine are calculated and the put-in force of that spindle is decided. After that, the axial deformation of toolholder, drawbar, Belleville spring, rotor and taper between toolholder and rotor are computed. Finally, the pre-load of Belleville spring is adjusted to keep the bending stiffness, drivable torque and put-in force of spindle adequate at 120,000 rpm