Cutting Mechanisms and Their Influence on Dynamic Forces, Vibrations and Stability in Micro-endmilling

A dynamic cutting force and vibration model of the microendmilling process that accounts for the dynamics of the microendmill, influences of the stable built-up-edge, and the effects of minimum chip thickness, elastic recovery, and the elastic-plastic nature in ploughing/rubbing has been developed. Experimental validation has been performed, and the model is shown to predict the cutting force and tool vibration within an average of 12%. Using the model developed, effects of the minimum chip thickness and elastic recovery on the cutting forces and vibrations as well as process stability of the micro-endmilling process have been examined. The results indicate that the large edge radius relative to the feedrate causes the process stability to be sensitive to feedrate, resulting in the low feedrate instability phenomenon. The elastic recovery significantly increases the peak-to-valley cutting forces and enlarges the unstable feedrate range.