In Europe a consortium has been formed to develop a Sensor Fused Intelligent Monitoring System for Machining (SIMON). Starting from a generic module structure for process monitoring systems, the system architecture of a fully control integrated monitoring system for rough milling operations is presented based on digital drive signals. Machine integrated sensors are used for calibration and for wear monitoring. The potential of such a system is shown by previous work at WZL. Experimental results demonstrate successful tool overload and tool breakage monitoring for milling and drilling, based on drive current signals. Comprised only of software modules, directly linked into an industrial open system controller, the base system does not need any sensor or signal processing hardware to monitor 06mm drilling or 08mm end milling tools machining steel workpieces. Signal correction has been designed for monitoring during acceleration. Machine integrated sensors are presented to extend the range of reliable monitoring.