<p>Optimal selection of process parameters based on stability lobe diagrams (SLDs) is one of the common methods to avoid chatter in milling operations. The state-of-the-art research reveals that vibration displacement exerts a considerable effect on the regenerative stability, especially for milling operations of flexible parts. Nevertheless, it has not been extended to five-axis milling, in which the cutter workpiece engagement (CWE) is too complicated to analytically incorporate the effect of vibration displacement. This paper presents a new dynamics model for five-axis milling of flexible parts by considering the effect of three direction vibration displacements. Firstly, a novel solid-segment intersection method is proposed to accurately calculate the five-axis CWE in an efficient way with considering the feedback of vibration displacements. Secondly, the mechanistic model is used to formulate the milling forces by discretizing the general milling tool into cutting elements along the tool axis. The dynamics model is finally established as a second-order differential equation and then an iterative time-domain algorithm is proposed to calculate the steady time history vibration displacement. The regenerative stability is determined by performing stroboscopic sampling on the simulated vibration displacement. Five-axis cutting experiments on a flexure-fixed workpiece validate that the predicted chatter stability matches well with the experimental results for the most majority of cutter locations. It verifies that the proposed solid-segment intersection method is effective to capture the true five-axis CWE and the presented dynamics model with considering the effect of vibration displacement is accurate for five-axis milling of flexible parts.</p>