用反圆环面刀加工变曲率过渡曲面原理

基于宽行加工理论和广域曲率吻合原则,提出一种利用圆环面内侧作为刀具工作面的反圆环面刀具宽行加工叶片进排气边的新方法.该方法通过优化刀具摆角使具有定母圆半径刀具工作面的包络面充分逼近叶片进排气边曲面,从而使刀具能在给定的精度范围内以最大行宽和最少刀轨行数加工出进排气边.最后,以某型号发动机叶片的进气边为例进行了加工实验.结果表明该方法能够大幅提高进排气边的加工质量,且反圆环面刀的加工行宽比球头刀提高了5倍.

Principle of machining variant curvature blending surfaces with counter torus cutter

Based on the stripe-width-maximization machining theory and the principle of global curvature fitting,a novel counter torus cutter,which uses the inner surface of torus as the cutting edge,was proposed to machine the leading and trailing edge of a turbine blade.Through optimizing the raw angle of the counter torus cutter with a circular generatrix of given radius,the envelope surface of the tool can closely approximate the leading and trailing edge surface of the turbine blade with variant curvature,which can be machined by maximizing the machining strip width and minimizing the number of tool paths under a given tolerance.An experiment to machine the leading and trailing edge of an aero-engine turbine blade was carried out.Results illustrate that the proposed method could greatly improve the machining quality of the leading and trailing edge,and the machining strip-width using a counter torus cutter is 5 times larger than that using a ball nose cutter.