Machining vibrations, a.k.a. chatter, lead to affecting the surface roughness and shortening the life of spindles and tools in machine tool industry. Reducing the depth of cutting is conventionally used to suppress the chatter. However, if the depth of cutting is reduced, the machining efficiency is decreased, too. If the vibration can be controlled, the depth of cutting can be increased, and the efficiency can also be improved. Therefore, an active damping system is introduced in this article for vibration suppression. During the processing, the vibration can be reduced by the active damping system.