自由曲面叶轮的四坐标数控加工研究

 针对自由曲面叶轮的四坐标加工，提出了一种刀轴矢量的确定方法。给定工作台倾斜角度和刀具后跟角，四坐标加工的刀轴矢量必然位于这两个角度确定的两个圆锥面上。通过对两个圆锥面求交并结合叶轮加工的实际特点，给出了自由曲面叶轮四坐标加工刀轴矢量的计算方法。根据得到的刀轴矢量，计算相应的侧偏角，从而可将五坐标加工的理论和方法直接应用于四坐标加工中。算例表明，该方法合理可行，能够有效提高四坐标加工效率、降低叶轮加工成本，并可推广至一般曲面的四坐标加工以及五轴四联动加工。

Research on 4-axis Numerical Control Machining of Free-form Surface Impellers

A new tool axis determination method in 4-axis NC machining of the free-form surface impellers is presented.For 4-axis machine with oblique rotary working table,the opposite rotary motion of the tool axis forms a cone which is depended on the table angle.During the tool path planning process,the tool axis also locates on the other cone determined by the predefined inclination angle.Therefore,the tool axis of 4-axis machining can be obtained from the intersection lines of the two cones together with the consideration of the impeller machining characters.After the tool axis is achieved,the corresponding tilt angle is computable accordingly.Based on the inclination angle and tilt angle,the tool path generation method of 5-axis machining can be transferred to 4-axis machining directly.Examples verify the method is correct and reliable,and the results show that the machining efficiency of 4-axis machine is increased obviously and the cost of free-form surface impeller machining is decreased.Meanwhile,the method can be extended to 4-axis machining of general surfaces or 5-axis machining when only 4-axis is employed.