Self-excited vibrations in milling, commonly known as chatter, are undesirable vibrations that occur during the machining process. They result from unstable cutting conditions, often due to factors like tool geometry, cutting speeds, and workpiece material properties. These vibrations negatively impact machining precision, surface finish, tool life, and stability of the machining process in general. To avoid the mentioned negative effects, when defining cutting regimes diagrams are applied, which, depending on the spindle speed and cutting depth, illustrate the boundary between stable and unstable working area of the machine tool from the self-excitation vibrations point of view. These diagrams, known as “stability lobe diagrams,” can be defined using mathematical models (analytical or numerical) or through experimental methods (such as the tangent method or sound mapping). This paper presents a newly developed numerical simulation of the milling process which aims to define the limit depth of cut, i.e. the cutting depth at which self-excited vibrations occur. To verify the proposed method, experimental tests of self-excited vibrations during the milling of aluminum Al7075 were carried out at the EMCO ConceptMill 450 machining center.