Full life-cycle cutting force prediction in ball helical milling based on oblique cutting analysis

Abstract

Abstract In order to predict the change of cutting force in ball helical milling of titanium alloy, considering the kinematics of helical milling and the geometric model of ball end cutter, the cutting process is divided into three stages, cutting-in, steady and cutting-out stages, and the shape and volume of undeformed chip in different stages are described. Then according to the oblique cutting theory and the principle of maximum shear stress, the constraint relationships among the parameters such as friction angle, shear angle and shear stress in the micro-element are established. Thus based on the position parameters at different stages, a three-direction full life-cycle cutting force model is established, the cutting force coefficients are identified and expressed as Weibull functions of instantaneous undeformed chip thickness. Finally, the predicted cutting forces are compared with the experimental values. The results show that the maximum average error is less than 18%, which verify the accuracy of the model.