This paper presents a time-domain dynamic model, which simulates cylindrical plunge grinding processes under general grinding conditions. The model focuses on the prediction of grinding chatter boundaries and growth rates. Critical issues are considered in the model including: the distributed nonlinear force along the contact length, the geometrical interaction between the wheel and workpiece based on their surface profiles, the structure dynamics with multiple degrees of freedom for both the wheel and workpiece, the response delay due to spindle nonlinearities and other effects, and the effect of the motion perpendicular to the normal direction. A simulation program has been developed using the model to predict regenerative forces, dynamic responses, surface profiles, stability regions, and chatter growth rates. The model is validated using existing numerical and experimental results.