Analysis of cutting stability in vibration assisted machining using an analytical predictive force model
Vibration assisted machining (VAM) adds sinusoidal tool vibration to the conventional machining (CM) process. It is generally recognized that VAM can effectively improve machining quality and machining efficiency, however, the theoretical basis for this is not fully developed. One feasible explanation is about the improvement of cutting stability. In the previous literatures, time-domain simulations of chatter for CM and VAM have been compared, showing VAM can suppress chatter and increase cutting stability under various conditions. However, the stability lobe diagram that gives a global picture of the stability behavior is still unavailable for VAM. This paper is dedicated to draw the stability lobe diagram for VAM and compare it with that for CM. An analytical predictive force model is developed to determine the dynamic cutting force in VAM, incorporating material properties, tool geometry, cutting conditions and vibration parameters. Then a stability analysis based on the proposed force model is done and the corresponding stability lobe diagram is obtained, which shows the effect of VAM on cutting stability on a large spindle speed scale. Finally, cutting experiments about surface roughness are carried out to verify the theoretical conclusion.