A PREDICTIVE FORCE MODEL IN BALL-END MILLING INCLUDING ECCENTRICITY EFFECTS

In this study, a new predictive force model in ball-end milling has been derived from a metal cutting theory and for the geometric relations of the ball-end milling process. It was necessary initially to define the cutting edge shape and then to determine the tool geometry of each cutting edge element by simple geometric procedures. The cutting edge on a ball-end mill can be considered as the curve of an intersection of a spherical surface with a skew plane. The advantage of this method is that the effects of the various parameters concerning the oblique cutting process can be readily calculated. The force model developed considers many of the process variables as well as the eccentricity (run-out) inevitably found in practice. The predicted and experimental results show good correlation and highlight the importance of the eccentricity on the forces and their fluctuations.