Tool Point Frequency Response Function Prediction Based On RCSA In Spindle Tool System

Regenerative chatter occurred between end mill and tool piece results in unstable cutting process, poor surface quality and low material removal rate, even bring permanent damage to machine tool spindle system and end mill. This undesired self-excited vibration problem is one of the main obstacles in utilizing the total capacity of a machine tool in production. In order to obtain stability cutting zone, stability lobe diagrams plays a crucial role. Constructing the stability lobe diagram for a certain spindle-holder-tool combination implies knowing the tool point frequency response function (FRFs). In this paper, research related to tool point frequency response, such as dynamic model, coupling theory and prediction method is studied.Milling system dynamic model is established and model experiment is also operated. According to stiffness of end mill and tool piece, dynamic model can be classified to flexible end mill with rigid or flexible work piece. Present model analysis method based on impact experiment. Four main natural frequency of experiment cutter used in following prediction is obtained.In the process of obtain spindle system receptance by receptance coupling method, considering the influence of shear force and rotational inertia in calculation for structure receptance. Spindle structure deformation applied fore is complex. Receptance coupling method can reflects bending and torsional structure receptance comprehensively. At meantime, compared to structure receptance based on Euler-Bernoulli model, Timoshenko model which consider shear force and rotational inertia can precisely describe bend and shear deformation. Especially for the low length diameter ratio structure and situation that ratio sharply decreases when assembled.A tool point frequency response prediction method combined numerical calculation and impact experiment is presented. Frequency response of tool holder and assembly with test end mill is obtained by impact experiment. Then, joint part parameters will be defined combined with response numerical results of the test end mill. Then, using the previous results and numerical results of end mill that to be predicted, tool point frequency response can be obtained. This method can not only guarantee the prediction accuracy, but also reduce repeat impact experiment to achieve rapidly prediction.At the end, tool point frequency response prediction method is about to be tested by experiments. Prediction results show well agreement to the frequency response that direct obtained by impact experiment. Besides that, it also show more accuracy than Euler-Bernoulli model based approach, especially in magnitude improvement. The feasibility and accuracy is verified.