「旋風式銑削」是一種生產效率較高的螺桿加工方法，然而，過去國內外在加工「真空泵螺桿轉子」時多採用指型或盤型刀具進行成形銑削，加工效率低且難以製造具「變導程」及「變徑深」特徵之高性能螺桿轉子。因此，本計畫將在第一年度中，建立旋風式銑削變導程及變徑深螺桿轉子之座標系統及數學模型，以成形法設計刀盤及刀刃廓形，並推導CNC機台各軸之運動方程式，最終透過刀具軌跡及其包絡齒廓之誤差分析，驗證所提方法及數學模型之正確性。在第二年度中，將延續第一年之研究基礎進行CNC旋風式銑削機台之三維電腦輔助螺桿轉子加工模擬及分析，將經由刀具與工件實體差集後之加工轉子齒面，與理論目標轉子齒面進行法向誤差分析，利用刀刃廓形修形及加工軸運動進行誤差補償以產生所需轉子間嚙合間隙、提升加工精度，更研究刀具壽命、切削力及材料移除率以得到最適當之加工參數設定。本計畫之研究成果預期可提供國內開發旋風式銑削CNC機台之關鍵技術，並提供真空泵轉桿轉子一種新的高效率加工方法。 ;Whirling milling is a kind of high-efficient machining method for the screw manufacture. In the past, the form milling with the finger- or disk-type cutter is commonly used in the screw rotor manufacture for vacuum pumps, however, it is low-productivity and difficult to machine the screw rotor with a variable lead and a variable radial depth. In view of this, in the 1st year research work, a mathematical model will be established based on the relative motion coordinate system between the whirling milling cutter and the screw rotor. The cutter body and the cutting profiles are designed using the forming method, and the motion equation for each machining axis will also be derived. At last, the validity of proposed method will be verified through the analysis of rotor profile error enveloped by the CNC cutting trajectory. In the 2nd year research, the computer-aided simulation and analysis for the CNC whirling milling of screw rotors will be practiced with extending the 1st year research basis. The normal deviation between the simulated and the target rotor surfaces will be estimated and employed in the machining error compensation through the cutting profile modification and the cutting motion adjustment in order to obtain the required meshing clearance and increase the manufacturing accuracy. Further, the tool life, cutting force and material removal ratio will be investigated to attain the most adequate machine settings. The achievements of this project will provide key technologies for developing the whirling milling machine, and a novel and high-efficient machining method to the screw rotor for vacuum pumps.
