Numerical analysis and parameter study of a mechanical damper for use in long slender endmills

A mechanical damper has been introduced to reduce tool vibration during the high-speed milling process. The mechanical damper is composed of multi-fingered cylindrical inserts placed in a matching cylindrical hole in the center of a standard end-milling cutter. Centrifugal forces during high-speed rotation press the flexible fingers against the inner surface of the tool. Bending of the tool/damper assembly due to cutting forces or chatter vibration causes relative axial sliding between the tool inner surface and the damper fingers, and dissipates energy in the form of friction work. In this paper, a simple numerical method is presented to estimate the amount of friction work during tool bending. Non-linear static finite element analysis is used to estimate normal and frictional contact forces due to centrifugal forces and cutting forces, and calculate the amount of frictional work dissipated by the damper. The numerical results are compared with analytical results, and show a similar trend. Parameter studies are also carried out using the numerical model to identify the best configuration to maximize the amount of friction work.