Abstract: Robotic milling offers clear advantages for machining large and complex components;however,the high compliance of serial industrial robots and the pronounced pose dependence of their dynamics make it difficult to evaluate stability boundaries consistently across the workspace.This paper proposes a stability-boundary identification method for pose-varying robotic milling.Under steady cutting conditions,output responses are collected,and an improved stochastic subspace identification algorithm,developed to enhance computational efficiency,is used to rapidly extract key modal parameters at different poses.In addition,a standardized pose coordinate transformation is established to ensure that the identified modal parameters and stability indices are expressed in a unified reference frame,thereby improving the consistency and comparability of pose-to-pose evaluations.On this basis,a pose-dependent three-dimensional stability-domain map is constructed by integrating a regenerative chatter dynamic model,enabling stability prediction and process-parameter selection.Simulation and experimental results confirm the effectiveness of the proposed method and provide methodological support for stable process-parameter planning in robotic milling.