Study Of The Dynamic Characteristics Of High Speed Cutting Systems

HSM system (including machine tool, cutter, workpiece and cutting process) is a complex dynamic system. The dynamic characteristics of the HSM system influence and limit the reliability, safety, workmanship, efficiency, cost and the whole machining system. Therefore, the researches of HSM stability is an important fundamental project which can develop the HSM technology.Direct against the HSM characteristic, the dynamic characteristics and stability have been studied.We analyzed the regenerated vibrate, forced vibration and resonance mechanism, analyzed the amplitude magnification of the cutting state and the unload state under the situation of vibration, and established the HSM dynamics model.Take the main shaft, the shank and the cutter as examples, set up the dynamics model that considering the centrifugal force and turbinate moment, analyze the dynamic characteristic using the finite element method. Include mainly: Carries on dynamic characteristic analysis of the surface milling cutter, study the dynamic characteristic of the surface milling cutter with different diameters and number of teeth; Carries on dynamic characteristic analysis of the end milling cutter, study the dynamic characteristic of the end milling cutter with different diameters and length to diameter radio; Carries on dynamic characteristic analysis of the BT40 spindle/holder and the HSK63 spindle/holder, Study the impact on dynamic characteristic of the centrifugal force and turbinate moment, and analyze dynamic characteristic with different main shaft support. Analyze the dynamic characteristic of the BT40 spindle/holder and the HSK63 spindle/holder with different cutter and different speed. The result of calculation of number shows: The impact on the dynamic characteristic of the centrifugal force and the turbinate matrix is obvious with high speed; Because the HSK spindle/holder adopts the structure of two-sided connection, it is better than the one-sided connection.Analyze the turbinate system characteristic considering the high speed influences, provide the critical condition criterion of the HSM stability and the prediction analytical method of its limit of stability, give the limit stability calculational methods of the systems of single degree of freedom and many degree of freedoms. Appraisal the different machining center stability in two ways, one is to see whether the round of the biggest rotational speed is in the stabilizing area, the other is to depend on the product of the biggest rotational speed n in the stabilizing area and the biggest axial cutting depth b_lim.Design and implement the experiment of high-speed machining center and the dynamic experiment with high speed milling, identify different steps critical rotational speed of system, analyze the systematic dynamic characteristic with different machine tools, cutter, work piece under different cutting parameters, analyze the influence on cutting stability of different cutting conditions, the dynamics model and the number analysis of dynamic characteristic of the system has been verified, and draw the cutting stability limit picture by the experimental data, validate and revise the dynamics models.