螺杆转子5轴旋风式铣削的刀轨规划研究

Tool-path planning for five-axis computer numerical control machining of helical rotors with whirlwind milling method

根据螺杆转子的形素信息特征 ,提出了螺杆转子 5轴卧式数控旋风式铣削加工的新技术。研究了铣削加工刀具轨迹规划中的走刀步长、走刀步距和刀具姿态等参数以及转子螺旋曲面的几何特征以及螺杆转子的 5轴旋风式数控机床铣削原理等问题。此旋风式铣削技术是在走刀过程中实时地改变刀具的轴心线绕切触点工件曲面外法线向量转动的角度 ,即调整 5轴卧式数控机床沿第四、第五轴方向转动的角度来实施铣削加工。螺杆钻具转子表面是一种基本几何特征仅取决于其生成母线的特殊三维空间曲面 ,其端面截形的成形精度是决定螺旋曲面加工质量的主要因素。实际试样切削表明 ,5轴旋风式铣削技术是复杂螺旋曲面快速、高效、精确制造的一种可行技术 ,其成形精度高。在相同表面粗糙度要求的条件下 ,相对于普通 3轴数控机床 ,可使刀具切削行程减少 8.5 %～ 12 .0 % ,加工时间缩短 10 %～ 15 %。

On the basis of the geometrical characteristics of helical rotors and the features of five-axis computer numerical control horizontal milling technique,a new whirlwind milling method was presented. Some main geometrical properties of the rotor with helical curved surface were analyzed. The basic parameters for tool-path planning such as step-length,step-over and tilt angles were studied in detail. Some practical examples of the rotors manufactured with the new milling method were given. The application results show that the new method is an effective technique for machining the complex helical surfaces. If the tool-path is planned with a constant scallop height strategy,this new technique will reduce cutting passes over three-axis computer numerical control milling machines by 8.5 percent to 12.0 percent. Furthermore,it can shorten the machining time by 10 percent to 15 percent, compared with the traditional three-axis milling technique.