<p>Digital twin technology has multidimensionality and scalability, providing a solution for integrating different functions in the milling stability analysis process. This paper proposes the HIEE architecture (Highly Integrated and Easily Expandable digital twin system architecture) for the integration and expansion within digital twin systems. The architecture targets production environments with multiple machining units, establishing differentiated milling stability analysis strategies for various machine tools. Using the milling stability of titanium alloy thin-walled components with end mills as the research subject, the system facilitates the integration and enhancement of system functions by embedding modules such as cutting force calculation and stability prediction. The introduction of microservice technology in the HIEE architecture achieves load balancing between modules, while reducing the difficulty of development and functional expansion. Finally, the functionality of the system is validated through experiments on the milling process of titanium alloy end mills.</p>