In a competitive manufacturing environment, machining high precision components with narrow dimensional variations is vital. evidences show that the dimensional variations exist not only in a single point, but throughout the surface of the component. several researchers are working in this field to reduce these dimensional variations in the component. in this research, a new technology called portable intelligent system (pis) is introduced to reduce the component’s dimensional variations in cnc milling machine in real-time. the pis consists of various components, which includes both hardware and software. this system acts as an auxiliary device for cnc machine tools. this device has its own built-in controller, which has intelligence to monitor and control the dimensional variations to zero. this device is designed such a way that it can be mounted on any existing cnc vertical milling machine. a comparison study between conventional machining and precision machining using pis was carried out with 20 samples and their results show positive outcomes.