The efficiency of high-speed milling process is often limited by the occurrence of chatter. Active control systems seem to represent a suitable solution for chatter suppression, because of their high adaptivity. Nevertheless, efforts still need to be made for the definition of the best control strategy. Accurate simulation tools are therefore necessary, in order to take into account the effects of the actuating system on the cutting process. In this paper an efficient full-discretization method for active chatter mitigation simulation in milling process is presented. The time domain model has been developed considering an active workpiece holder driven by piezo actuators. The proposed simulation tool has been experimentally validated on a milling test case.