An accurate mathematical model for ball end mills with chisel edge

Ball end mills have complex geometry. The precision CNC grinding of the cutting edge on the spherical surface is a big challenge for the tool manufacturers. Regarding the design cutting edge, we propose a cutting-edge design model in which the cutting edge can be offset along the spherical surface. To improve the accuracy of this model, the twist drill chisel-edge was also introduced into this design model of cutting edge. Then, referring to the toolpath calculation method of complex surface machining, we established a method for grinding the rake face of the ball end mill using a 1A1 standard wheel. For the clearance of the ball end mill, we developed a method to grind the clearance of the ball end mill using an 11V9 standard wheel. Finally, the design model of cutting edge, grinding models of rake face, and clearance were verified by simulations and experiments, respectively. The results show the proposed cutting-edge model has a better profile tolerance. The intersection line between the rake face and clearance coincides with the design’s cutting edge. These prove the effectiveness of methods.